L/' s en me. 5: L I B HARY OF THE U N IVLRSITY Of ILLINOIS 590.5 Fl „. 53-54 BJOLOG* *v.; c material is re- The person charging this m { j£& lU? stamped bdow L161-O-1096 N CO lo N - ia a . « o. os i— i rL o> X t~ co ^"^ »— * co co JJ Tf< ■* £ r* t- ■<* CM ^» o, d o. a £j c£ «> 12 •> 2" H t- ^ t> 00 .S >> m O ai m 2 2 I g I §3 If J rt (1 JS +J ^-^ 3 rt eo O 01 *— • 3 c (1) a S (V «^ co • tt a> o • m 00 10 CO • CO CO CO tj< eg ■*«i>*oi> , *nt' o .0 i .23 a »-. o s '•3 •s. PO < "£3 HMUJOTfiO^OHM, O -u 000000©0©0© CO f. u u >cs o> CD 10 10 iio t^ 10 10 10 a. c d d D. S3 3 ad « ^ „ a d d t^" eo -M CO co 10 OS © © 1-H ©" 1 — < 01 ^, 1— 1 ^. o> a> SI " ' a> u M Qi c ■x. 01 (V IV a> s O « O ? 3 3 S Eh En C Eh Eh H K Eh co co co 00 CO 10 00 10 co tj< 00 WHlOt-tCNNOH 000000000 w 'E o 232 co OS >> T3 60 3 < w <^ CO C co ^ C oo hh ■>* C/J t> 73 ►* W O) co'O be & «- a) C + W t- I • r-l OS ja o • "«f CO o © eg • (M os • ■* — ^H t— • co CO • "* CO CO CO ■*• • co B © • © © o o © • © 1X1 «— o JO • © lO «o iH a> art O "5 O •~ © © 1 ■& 03 +j -u be £ + kO C0iOC0t>TfrJit-C0t~ (M(N^H N N N N 00 ©TfCM©W5U5Tft-00 CO ^ ^ ^* CO CO ^ CO 04 ©©©©©©©©© t-t-COiOOCOO^IM «CHH»NOSHt-T(l 233 234 FIELDIANA: ZOOLOGY, VOLUME 53 Fig. 5. Upper: pairs of teeth of four individuals of Hyperoodon ampullatus; the two pairs at left are immatures; those at right approach adulthood; all British Museum (Natural History) specimens from the British Isles, courtesy Miss J. E. King. Lower: pairs of teeth of three individuals of Ziphius cavirostris; all from La Par- guera, Puerto Rico, courtesy of Donald S. Erdman; the middle pair is of ad. 9, FMNH 95286; the left pair is ad. 9 and the right pair is ad. d", both lent from a private collection. Upper and lower in a single photograph, hence same scale. Fraser, 1953), the northern bottle-nosed whale which, because it occurs in European waters, is in many ways better known than the other living species, H. planifrons. So little is known about the nor- mal teeth of Hyperoodon ampullatus that it seems of value here to illustrate the normal teeth of several specimens of varying develop- ment. In Figure 4 the state of closure of the pulp cavities in these is revealed. The ones with the most open and deepest pulp cavities, presumably in a general way the youngest, are noted to have finger- like projections forming the rim around the pulp cavity which are, as far as I am aware, unique among the teeth of immature beaked whales, and may prove of value in distinguishing between teeth from immatures of H. ampullatus and those of Ziphius at least. In Table 1 closure of the mouth of the pulp cavity may be observed to progress with increase in body length of the animals, increase in dimensions of the teeth, and decrease in depth of the pulp cavity. MOORE: BEAKED WHALES 235 The shape of Hyperoodon teeth, described above as primitive, is shown in Figure 5 in contrast with teeth of three adult specimens of Ziphius cavirostris (left to right — 9 9 cf), all from Puerto Rico. Donald S. Erdman (1962) provided the larger pair of female teeth, together with the skeleton, from a 1961 stranding at La Parguera, P. R. (FMNH 95286), and Mr. Erdman lent the two other pairs from individuals in a stranding said by acquaintances of Erdman's to have involved four small whales at La Parguera, P. R., on or shortly before December 9, 1965. Adult Males of ampullatus. — Fraser (1949, p. 272) gives a de- scription of a pair of teeth taken from a 26-foot male, but I have found no publication of a first-hand description or illustration of the teeth of a male more definitely known to be fully adult, and identified as this species. Nor in examining 67 items in the scientific literature dealing with this species have I found clear reference to such a de- scription or illustration. The teeth that have been reported upon by scientists are almost exclusively of female or young specimens, which have stranded or been captured in coastal waters. Adult males are said to be seen far at sea where they have been sought at times by small commercial whaling vessels on which hazards of life and limb have been regarded so discouraging for whaling men as to be perhaps prohibitive for a scientist. To help me in this effort to evaluate relationships among the liv- ing genera of beaked whales, Dr. F. C. Fraser has generously meas- ured and sketched the tooth and alveolus of the skull of a fully adult male (BM 1889.11.6.1=1378 E) exhibited in the British Museum. Figure 6 shows the right tooth in situ on the apex of the right ramus of the mandible, and its measurements are shown in Table 1. It was evidently exposed in life, for the crown is worn off in an oblique plane tilted downward on the right. It is apparent from this and the teeth from young specimens of varying proximity to maturity, from the British Museum and lent by Miss J. E. King (see fig. 5), that the teeth of adult Hyperoodon ampullatus are characterized by a slight but definite bulbousness at the proximal end. This results in shape rather like a pear in that the profile of each whole tooth is convex near the proximal end but becomes slightly concave toward the apex. In this it differs from all living species of other genera of beaked whales (whose teeth are known) excepting Tasmacetus shepherdi (Oliver, 1937, pi. 4, fig. 10). This similarity and the very small proportional size of these apical mandibular teeth suggest that the teeth of Hy- peroodon ampullatus have not in fact developed or differentiated 236 FIELDIANA: ZOOLOGY, VOLUME 53 Fig. 6. Lateral view of right tooth of ad. 0) >. Q CO c Tj 0) £ a S Z *S E <*— o a * 3 4 Sffl 2^ 247 248 FIELDIANA: ZOOLOGY, VOLUME 53 The structure of the teeth of all these genera, when compared with those of one of the earliest fossil Hyperoodontidae, Diochoticus, are probably derivative in the sense of having: 1) become simplified in form of tooth (Tasmacetus, Hyperoodon, Ziphius); 2) radiated in- tragenerically in tooth size and structure (Mesoplodon); 3) become compressed (Berardius, Mesoplodon); 4) radiated to produce many species modified variously as to location of the pointed tip on the front, middle or rear of the top edge of the tooth (Mesoplodon). These factors taken together suggest for the living genera a linear scale of most-primitive-to-most-derivative as follows: Tasmacetus, Hyperoodon, Ziphius, Berardius, Mesoplodon. Within the genus Mesoplodon the inter-specific variation in loca- tion of the denticle on the body of the tooth is rather consistently associated with distance of tooth from the mandibular apex of the mandible and orientation of the tooth. By this set of three related variations the species may be linearly arranged on a most-primitive- to-most-derivative scale as follows: hectori, mirus, pacificus, euro- paeus, ginkgodens, grayi, carlhubbsi, bowdoini, stejnegeri, bidens, layardi, and not specifically at the end of this progression but apart from it, although otherwise one of the most derivative species because of the structural characteristics of the mandible of the male, is den- sirostris. Alveoli The alveoli of the teeth of Tasmacetus were described only as "shallow" by Oliver (1937, pp. 376, 377), but their pertinence to in- tergeneric relationships invites greater detail. Most alveoli of all the three specimens examined contained pads or platforms of delicate dendritic bone, rather similar in structure in some alveoli to the den- dritic lichens commonly called reindeer moss. In other alveoli, the branches of these dendrites apparently have become more fused with those of others and the structure of the platforms is more sponge-like. In the Dominion Museum specimen (no. 613), a mandible with which there were no teeth, the absence of these platforms from some alveoli led me to presume that the platforms represented a stage in the filling in of alveoli by bone where in life some teeth had been lost. The University of Canterbury Museum specimen (no. 1063), how- ever, had all of its teeth present, and all of the alveoli contained these bony platforms; hence, absence of some of these delicate structures from alveoli in other specimens is better explained by their having MOORE: BEAKED WHALES 249 been eroded away in handling as specimens, or in washing on the beach as bare bones. These bony platforms or pads in the alveoli of the mandibular teeth usually fill the rather shallow alveoli almost to the brim and generally leave a little space between the periphery of the pad and the rim of the alveolus. In the alveoli of the maxillary teeth the plat- forms may rise out of and above the very shallow alveoli. Thus, instead of teeth with a narrow root secured deep in a bony socket as in Mesoplodon, Tasmacetus has teeth with swollen, bulbous roots which sit upon platforms of dendritic or spongiform bone in very shallow alveoli. The apical, larger pair of teeth in Berardius have shallow alveoli with spongiform or grossly cancellous pads in their bottoms. These are proportionally deeper alveoli than those of Tasmacetus, but proportionally much less deep than those of Mesoplodon. Nothing is yet known about female teeth in Tasmacetus, but sex- ual dimorphism, if any, present in the teeth of Berardius was not detected by Omura et al. (1955, table 4), nor demonstrated by Kirino (1956, p. 432), although the latter then thought it would be possible to show that "the teeth of the female are, statistically speaking, in- ferior to those of the male in all their dimensions." Be that as it may, the teeth of the female Berardius do erupt, wear away at the apex, and approximate (if not equal) the size of male teeth (Omura et al., 1955, table 4). In view of the relative, if not complete, lack of sexual dimorphism in the teeth of Berardius, and the evidence of close rela- tionships between Berardius and Tasmacetus presented here, it would now seem especially unwise to anticipate that strong sexual dimor- morphism will be found in the teeth of Tasmacetus. It may have become apparent from the above that comparisons of the alveoli of the mature, erupted teeth of Tasmacetus and Berardius need to be made with those of the adult male teeth (not female) in the other genera. In Ziphius, only teeth of adult males have been shown to erupt and wear; those of females do not (True, 1910, p. 57; Fraser, 1942, p. 29) erupt but remain cryptic in the alveolus beneath the gum. In the male of Ziphius as it grows older, ". . . passage from the cylindrical to the fusiform shape ... is brought about ... by an absorption of the tooth root, a wearing down of the [exposed apex], and a very great thickening of the [remainder of the tooth by] in- vesting cement" (Fraser, 1942, p. 29, and pi. 2, c to h). On the pertinent matter of the alveolus, True (1910, p. 57) has noted, ". . . in adult males the teeth are almost entirely protruded from the alveoli, 250 FIELDIANA: ZOOLOGY, VOLUME 53 which are filled with a coarse bony network." That this is very sim- ilar, indeed, to the apical alveoli of Tasmacetus and Berardius is obvi- ous, for example, in True (1910, pi. 23, fig. 1), where pads or platforms of dendritic or spongiform bone may be seen in a male Ziphius. Fig. 11. Dorsal view of apex of left ramus of the mandible of an adult male Hyperoodon ampullatus, BM 1889.11.6.1, showing the alveolus. Compare descrip- tion in text. From an original sketch by F. C. Fraser. In Hyperoodon there is strong sexual dimorphism in the teeth of the southern species planifrons. The tooth of the one adult female known remains slender and unerupted (McCann, 1961, pi. 1, fig. 8), but that of the one adult male known erupts, wears (most peculiarly), and grows stout (Hale, 1931, fig. 11). Comparison with photographs of these same male teeth in place (Hale, 1931, figs. 9, 10) reveals that at least half of their length (57 and 59 mm.) protrudes above the bone of the alveolus. The implicit alveolar depth of only about 30 mm. suggests that the alveolus in the adult male of this species must also be filled in with bone, as noted above in Ziphius. No published observations describing or illustations depicting the alveolus in adult males of Hyperoodon ampullatus have come to my attention, and here, as in the case of the tooth of an adult male of this species, Dr. F. C. Fraser has generously contributed notes and a sketch (fig. 11) describing the structure of alveoli of the jaw of an adult male on exhibit in the British Museum (Natural History). "On the left ramus of the mandible the area of the alveolus is dis- tinguished by irregularly pitted bone the outer margin of which is ill-defined but roughly pyriform in shape and measures 41.2 mm. long and 27.2 mm. wide. The stem end of this pear-shaped alveolar area is directed posteriorly and narrows sharply to connect with the per- sisting linear vestige of the mandibular toothrow (see fig. 6). On this MOORE: BEAKED WHALES 251 left ramus there is a central cavity in the alveolus surrounded by the irregularly pitted bone. The somewhat egg-shaped margin of the central cavity measures 13.5 mm. long, 9.1 mm. wide, and 6.6 mm. deep. The walls of this central cavity are finely ridged, the ridges descending focally from the external margins of the cavity toward the deepest point. The deep smaller pits around the central cavity occur also around the right tooth. A seeker could be passed into some of them quite far, and they may be nutrient foramina. Although the base of the tooth seems to be resting on the irregularly pitted surface of the right alveolus and no central cavity can be seen beneath the tooth, the latter is firmly wired down to the jaw so that presence or absence of a central cavity remains uncertain." Central cavity or not, the right tooth appears (to me as well as to Dr. Fraser), by its shape, to be evidently resting upon the shallow irregularly pitted surface of the alveolus, not imbedded in the bone. Even from this somewhat equivocal sample of one, I am encouraged by the similarity of structure of the teeth of Hyperoodon ampullatus to those of Tasmacetus shepherdi, to predict that when the alveoli of other adult males of H. ampullatus are examined they will also be Fig. 12. Dorsal view of alveoli of immature specimen of Hyperoodon ampul- latus, FMNH 15553. Left alveolus is natural; right alveolus has some artificial filling in which a tooth was once set while the skeleton of this specimen was on exhibit; some artificial material separates the rami; a nut is seen for a bolt holding the rami together. 252 FIELDIANA: ZOOLOGY, VOLUME 53 found to have filled up the deep alveolus of immaturity with cancellus bone. The tooth will presumably be imbedded in tough connective tissues of the gum, with only a small part of the tip erupted and wear- ing off. The specimen of an immature of H. ampullatus in Chicago (FMNH 15553) has an alveolus adequately deep (fig. 12) to accom- modate teeth up to 35 mm. long without erupting them through the gum if, as I assume, there is about 5 mm. of tissue separating the tooth from the bone in the alveolus, and about 10 mm. or more of tissue covering the bone externally. (The degree of immaturity of FMNH 15553 is indicated by the fact that on its mounted skeleton the sutures separate the epiphyses from the centra very openly on the thoracic, lumbar, and most of the caudal vertebrae, and that the epiphyses at both ends of the humerus, radius, and ulna are still free.) If such an individual were male, presumably in life the tooth would be gradually extruded from the alveolus and the latter filled up be- neath it during the course of morphological maturation. If it is cor- rect to assume, as the present investigator does from the sheer plan- ing off of the apex by wear, that the margin of wear is essentially the gum line, then the gum would need to become about 30 mm. thick to accommodate a tooth so extruded as that in Figure 6. For those species which are now best known of the genus Meso- plodon, in the adult male just as in the adult female and immature, the roots of the large pair of teeth remain long, and they remain sheathed in deep alveoli which thus do not fill with cancellous bone. Fraser (1946, fig. 11) has illustrated this for an adult male of species bidens by photographs of the lower jaw with tooth in situ and the mate of the tooth separate and posed well to show how deeply the root of the other is sheathed in the jaw. Raven (1942, figs. 4, 13, 16) and Moore (1958, figs. 4, 5) illustrate from both front and side the jaws of adult males of species densirostris with teeth in situ and then the teeth separately, permitting one to observe that about 75 mm. of the 150 mm. length of tooth may fit into the alveolus. In van Beneden and Gervais (1880, pi. 24, figs. 2, 2a, 3b) and Moore (1960, figs. 1, 2, 4) one observes that the teeth of adult males of europaeus may be sheathed in the alveolus for half or more than half of the length of the tooth. Flower (1878, pi. 72, fig. 3) and Lydekker (1911, fig. 138) provide some indication of this depth of alveolus for adult male specimens of grayi (see also fig. 3). True (1910, pi. 12) and Moore (1963b, figs. 6, 8, 9, 10) show somewhat better how much of the length of the tooth fits into the deep alveolus in adult males of stejnegeri, and the latter (op. cit., fig. 12) shows the tooth of the type MOORE: BEAKED WHALES 253 specimen of bowdoini in place in a lateral view of the mandible. Harmer (1924, pi. 3) presents a photograph of the lateral view of the mandible of the only known fully adult male of mirus with the teeth in situ so that one can see how much depth of jaw there is for the teeth to be sheathed in, but he did not take a tooth out to reveal the length of its root. Above it is reported that, although its teeth are still unknown, the alveoli of an adult, presumed male of pacificus are 26 mm. deep. These are proportionately the shallowest alveoli attributed to the genus Mesoplodon, and indeed provide the first good evidence for separating this species from that genus. Nishiwaki and Kamiya (1958, pi. 5, 10) show that about half of the length (apex to root) of the tooth in the adult male type of ginkgodens is sheathed in the bony socket of the cleaned jaw. Moore (1963b, figs. 8, 15) re- veals that the deep alveolus of the adult male type specimen of carl- hubbsi accepts about a third of the length of its (133 mm.) tall tooth. Thus, the alveoli of morphologically mature males of nine species of Mesoplodon evidently remain much deeper in proportion to the length of the tooth than is observed in the other genera. At the primitive end of a primitive-derivative gradient constructed on alveolar characteristics alone, we place Tasmacetus and Berardius together because the alveoli of males and females are presumed (in Tasmacetus) or known (in Berardius) to be alike, whereas in other genera sexual dimorphism is exhibited in the characteristics of the alveoli of adults. Alveoli of Tasmacetus seem to me to be more prim- itive than those of Berardius because those of the three Tasmacetus examined are shallower in proportion to length of tooth. Among the three genera which are relatively derivative because they exhibit sexual dimorphism in characteristics of the alveoli, Ziph- ius may be placed nearest the primitive end of the scale. This is because the alveoli in males of Ziphius that are morphologically quite mature show that their alveoli become exceedingly shallow and may even form sponge-like bone pads similar to those of Tasmacetus. (See illustrations by True, 1910, pi. 23, figs. 1, 2.) Scarcity of evidence on the alveoli of adults of the species of Hyperoodon weakens any assess- ment of where Hyperoodon may belong on the gradient of most prim- itive to most derivative alveoli, but even on this weak evidence it seems better tentatively to regard it as more derivative than Ziphius. Mesoplodon, because of the deep alveoli sheathing long roots of teeth of its morphologically mature males, belongs at the most de- rivative end of a scale based on alveoli. In the end then, if the assumptions made are correct, these alveolar characteristics give us 254 FIELDIANA: ZOOLOGY, VOLUME 53 Tasmacetus, Berardius, Ziphius, Hyperoodon, and Mesoplodon as the order of most primitive to most derivative, and the greater gaps be- tween them should come between Berardius and Ziphius and between Hyperoodon and Mesoplodon. The alveoli of the type and only adult specimen of Mesoplodon pacificus Longman, 1926 have led me to believe that it represents a male, and because their depth is only 26 mm., which is proportion- ately very much shallower than those of other adult male specimens of the species of Mesoplodon, I have expected that the second speci- men would require creation of a new genus. After this paper was some months in press, Dr. Maria Luisa Azzaroli of the University of Florence, Italy, sent me photographs for identification of a skull of an immature individual of M. pacificus Longman from the Somali Coast. The dorsal surfaces of the vertex of this skull are natural; whereas those of the type specimen are badly abraded. The differ- ences in the shapes of the nasal bones and premaxillary crest on the Somali skull support the evidence from the alveoli of the type that this species is generically distinct. The following name is therefore suggested : Indopacetus new genus Type species. — Mesoplodon pacificus Longman, 1926. Distribution. — Queensland east coast at MacKay, Somalian east coast at Danane. Description. — A beaked whale known only from two skulls, which are distinguished by: 1) a deep horizontal groove in the maxillary bone just above the orbit; 2) premaxillary crest with extremely short posterior processes; 3) nasal bones which neither project forward midsagittally where they meet at the anterior edge of the vertex, nor are grooved by a deep-walled sulcus there, but are only slightly in- dented there by the flat surface of each nasal sloping slightly toward the middle. See also: "Generic Diagnoses" and "Key for Characters of the Skull." The Elevated Synvertex One of the characters of the skull that distinguishes the living genera of beaked whales (Flower, 1872, p. 204) is that bones of the cranium behind the superior nares are elevated so as to form a prom- inence or crest at the vertex of the skull. Flower (1872, p. 204) lists seven skull characters as common to the living genera of beaked whales then known. More recent discovery of a new living genus, MOORE: BEAKED WHALES 255 Tasmacetus Oliver, 1937, belonging in the beaked whale family, has reduced those familial characters of the skull which still apply to all living genera to five. Of these five, the elevation of the vertex is the most conspicuous. For the living genera of the family, this character may be further defined: when the skull is upright and the long axis of the beak is horizontal, the premaxillary bones rise behind the supe- rior nares until: 1) In lateral view their profiles at least reach the vertical (as in all but Berardius) ; or 2) When viewed from front or rear on the line of the long axis of the beak, the vertex stands so high above the supraoccipital that the profiles of the sides of the vertex are seen to be at least vertical (as in Berardius and Tasmacetus) ; or both 1 and 2 (as in Tasmacetus). The vertex of a skull is by definition the highest point on it, but I find it useful in this family to coin a word syn vertex (Greek prefix syn-, meaning together with) to include a small area usually elevated high above the rest of the skull, illustrated in Figure 13. The bones constituting this specially-elevated synvertex characteristic of the Hyperoodontidae are: 1) The nasal bones are usually the most central, but when short may share this location with an intrusion of both frontals from posteriorly; 2) The upturned posterior extremities of the premaxillary bones generally form most of the front of the syn- vertex. Here the premaxillaries are separated narrowly or widely by the nasals, and insert a narrow posterior process of bone alongside each nasal ; 3) The thin layer of maxillary plate usually rises vertically to form the sides of the synvertex; 4) The supraoccipital rises high enough in most species to contribute the back edge of the synvertex, and it often forms an irregularly median wedge which spreads the frontals mildly; 5) The frontals usually form the smallest or least conspicuous part of the synvertex, posterior to the nasal bones. An important feature across the front of the synvertex is the pre- maxillary crest. This is principally formed by the widening of the upturned posterior ends of these bones, but in many species there is also a thickening of the premaxillaries, and in some a pronounced curl- ing forward of its top. The Premaxillary Crests In Berardius the postnarial ascension of the premaxillary bones to the synvertex does not reach or even approximate an angle perpen- dicular to the long axis of the beak-like rostrum. This is the only living genus of the Hyperoodontidae for which this is true, and since this condition of Berardius is nearer the common one of other Ceta- 256 MOORE: BEAKED WHALES 257 Fig. 14. Left lateral view of synvertex of skull of Berardius arnuxi, DM 183, illustrating the characteristic unique among living genera of beaked whales that the profile of neither premaxillary bone rising to the synvertex reaches a position perpendicular to the long axis of the beak. cea, Berardius is to be regarded as less derivative than the other hyperoodontid genera in this respect. This characteristic is illus- trated in Figure 14 in which the long axis of the beak of the specimen and of the camera frame were carefully ascertained to be horizontal for this photograph. That the axis of the beak would therefore be parallel to the horizontal edges of the finished halftone has been checked against the frame of the original negative. Another dis- tinctive characteristic of the elevated synvertex in Berardius is the exceedingly small amount of either widening or thickening of the ele- vated posterior extremities of the premaxillary bones (fig. 19) where these dimensions constitute by definition what little there is of a pre- maxillary crest. In Ziphius there is little or no thickening of the upraised posterior ends of the premaxillaries to contribute to a premaxillary crest. The Fig. 13. Synvertex of the skull of Mesoplodon grayi, an adult 9 , USNM 49880: right premaxillary bone (a), right nasal bone (b), right frontal bone (c), right maxillary bone (d), supraoccipital bone (e) fused with both frontal bones. This shows how the premaxillary crest is wide and thick, that the nasal bones ex- tend farthest forward at the side, and that a sulcus, U-shaped in cross-section, extends down the front of the combined nasal bones. 258 FIELDIANA: ZOOLOGY, VOLUME 53 Fig. 15. Dorsal view of syn vertex of skull of Ziphius cavirostris, FMNH 99362, showing the premaxillary bones (a) to be narrow and thin but strongly turned forward, and the nasal bones (b) to extend farthest forward mesially. Also marked are: right frontal bone (c), right maxillary bone (d), and supraoccipital bone (e). left premaxillary narrows rather than widens, and although the right one does widen, it is so incipient, so feebly developed, that, as in Berardius, it would hardly be called a crest but in deference to its better development in the other genera. There is development in the premaxillary crest of Ziphius which is peculiar to this genus: both the right and left parts of the crest are turned so that the anterior fronts of the crest face inward some 30 to 45° from straight forward, as shown in Figure 15. In Tasmacetus there is a substantial widening of the upraised ends of both premaxillary bones to form a more respectable premax- illary crest (fig. 17) than is found in either Berardius or Ziphius. The middle of the anterodorsal edge of the upcurled posterior end of each premaxillary does also thicken notably, so that both parts of the two- parted premaxillary crest do in Tasmacetus develop this second compo- nent which characterizes the more fully developed crests in relatively derivative genera. In Indopacetus the lateral expansion of the ends of the premaxil- lary bones to form the premaxillary crests exceeds that observed in MOORE: BEAKED WHALES 259 Tasmacetus and also that observed in Mesoplodon hectori. The pos- terior process of each side of the premaxillary crest extending along- side the nasal (illus. for Mesoplodon stejnegeri by Moore, 1963, fig. 3) is poorly developed and far shorter than in Tasmacetus. The right and left parts of the crest are also thickened anteroposteriorly. The form of the premaxillary crest is not penetrated and contributed to by an anterior process of the nasal as in Mesoplodon and Hyperoodon. In lateral view like that of Tasmacetus the profile of the premaxillary crest of Indopacetus barely rises to vertical to the long axis of its beak. In Mesoplodon the upturned, postnarial part of the premaxillaries widens and thickens prominently in each of the living species, al- though in hectori the thickening is both more pronounced than the widening and located separately above the widened part on both bones, so that thickening characterizes only the higher part of the pre- maxillary crest and widening only the lower (Fraser, 1950, pi. 3, figs. 1, 2). In the genera Mesoplodon and Hyperoodon the part of the premaxillary crest formed by the right premaxillary bone accepts into its own form an intrusion of the lateral process of the right nasal Fig. 16. Dorsal view of synvertex of skull of Hyperoodon ampullatus, FMNH 15553, immature, showing: very wide development of premaxillary (a) in crest; extreme thickness of premaxillary in crest; greatest participation of nasal bones (b) in the premaxillary crests by penetration of the very form of each premaxillary and partial replacement of it; the U-shaped depression in the combined nasal bones is wide and shallow in this immature specimen but becomes narrow and deep in adults (Gray, 1846, pi. 4); the wide sutures facilitate distinction of frontal bones (c), maxillary bones (d), and the supraoccipital (e). 260 FIELDIANA: ZOOLOGY, VOLUME 53 bone. In many but not all species of Mesoplodon and Hyperoodon the lateral process of the right nasal extends quite far forward into the premaxillary crest. Examples best illustrated are M. europaeus (Raven, 1937, fig. 8), M. layardi (Hale, 1931, fig. 20), M. hectori (Fraser, 1950, pi. 3, fig. 1), M. grayi (fig. 13, the present paper), M. ginkgodens (Nishiwaki and Kamiya, 1958, pis. 3, 4), and M. carl- hubbsi (Moore, 1963b, fig. 13). In Hyperoodon ampullatus the widening and thickening of the pre- maxillary crest is as fully developed (fig. 16) as in any species of Mesoplodon, and this is true also of H. planifrons. In this genus, also, occurs the derivative extreme in the premaxillary crest for consistent curling forward far over the nares. For characters of the premaxil- lary crest, therefore, Hyperoodon represents the derivative extreme of the living genera of its family. From the most primitive to the most derivative in characters of the premaxillary crests the genera should therefore be arranged as follows: Berardius, Ziphius, Tasmacetus, Indopacetus, Mesoplodon, Hyperoodon. Berardius and Ziphius are most distant from each other and about equally from Tasmacetus. Mesoplodon, with its many spe- cies, bridges the differences between the premaxillary crests of Tas- macetus and Indopacetus and those of Hyperoodon, the most primitive of Mesoplodon (hectori) resembling the former, the most derivative (carlhubbsi, bowdoini, layardi) resembling Hyperoodon ampullatus. Ziphius has developed in a different direction from the other genera in the form of its premaxillary crests as well as that of its nasal bones. The Nasal Bones Centrally located on the synvertex of the skull, the paired nasal bones also extend anteriorly and down from the synvertex to the mesethmoid bone (fig. 17) which, like the anterior faces of the nasals, provides part of the posterior wall of the superior nares. The right nasal bone is the larger of the pair throughout the living members of the family; it is generally wider, reaches higher, and its lateral process (present in Mesoplodon and Hyperoodon) projects anteriorly farther than does that of the left nasal. The configuration of the nasals as Fig. 17. Dorsal view of synvertex of skull of Tasmacetus shepherdi revealing the considerable widening of the premaxillaries to form the crest, and the nasals showing neither a deep median sulcus nor a median anterior projection on the (level of the) synvertex. Right premaxillary bone (a), right nasal (b), meseth- moid (c), right maxillary bone (d), right frontal bone (e), supraoccipital bone (f), left frontal (g), left naris (h). Photo courtesy of Dr. George Knox, UCM 1063. 261 262 MOORE: BEAKED WHALES 263 they rise from the mesethmoid to the synvertex is markedly different in two groups of the genera of the family of beaked whales. In Tasmacetus: 1) Where the nasal bones approach the anterior margin of the synvertex of the skull, they may be observed to be flat in postero-dorsal view. There is no most-anterior projection of the nasal bones; the middle and the sides are about equally anterior. 2) In their ascent from the margin of the mesethmoid bone to the synvertex, the nasal bones incline posteriorly from the vertical and reveal in lateral view a virtually flat profile (fig. 18) . 3) At the ante- rior margin of the synvertex the premaxillae project farther forward than do the nasal bones. In Indopacetus: 1) At the anterior extremity of the dorsal surfaces of nasal bones on the synvertex of the skull, they are slanted inward toward the suture between them, resulting in a slight indentation in their anterior margin, and permitting the lateral extremity of the right nasal to project slightly farther forward than any other part of the nasal bones on the surface of the synvertex. 2) In lateral view the profile of the right nasal bone rises from obscurity in the nares on a nearly straight line just perceptibly slanting posterior of vertical (to the long axis of the beak). 3) At the anterior margin of the syn- vertex the premaxillae project farther forward than do the nasal bones. In Berardius: 1) Where the anterior surfaces of the nasals ap- proach the synvertex, in dorsal view they are seen to be convex, and the most anterior projection of the nasal bones is at their mesial mar- gins, where they meet (fig. 19). 2) In their rise from the margin of the mesethmoid bone to the synvertex, the profile of the nasal bones rises vertically at first then declines progressively to the rear, and so in lateral view is seen to be convex. 3) At the level of the premaxillary crests the nasal bones project anteriorly farther than do the crests. In adults of Ziphius: 1) In dorsal view the anterior face of the nasal bones becomes convex near the synvertex, and their most ante- rior projection is at, or nearly at, their mesial margins where they meet (fig. 15). 2) Ascending, the concave anterior faces of the nasals in lateral view incline forward from the vertical (when the skull is upright and the long axis of the beak is horizontal), then, a few centi- FlG. 18. Left lateral view of skull of Tasmacetus shepherdi illustrating its more derivative condition than Berardius in that the rise of the premaxillaries to the synvertex attains an angle vertical to the long axis of the beak: right premaxil- lary (a), left premaxillary (b), right nasal (c), left nasal (d), left maxillary (e), mesethmoid (f). UCM 1063. 264 FIELDIANA: ZOOLOGY, VOLUME 53 Fig. 19. Dorsal view of synvertex of skull of Berardius arnuxi DM 183, illus- trating the narrowness and thinness of the upturned ends of the premaxillaries (a), hence the most meager of premaxillary crests among the genera of beaked whales (compare with fig. 13), and that on the synvertex the nasals (b) extend farthest forward mesially. Also identified are the frontals (c), the maxillaries (d), and supra- occipital (e) bones. meters before reaching the anterior margin of the synvertex, change to convex. 3) At the anterior margin of the synvertex of the skull the nasal bones project anteriorly separate from and farther than the premaxillary crests. In Hyperoodon: 1) Where the anterior surfaces of the nasal bones reach the synvertex, a horizontal plane would transect their combined surfaces in a concave arc, and the most anterior projection of the nasals is near the lateral margin on the lateral process of the right nasal (see fig. 16) . 2) In lateral view of the ascent of the nasals from the margin of the mesethmoid, the mesial portion of the anterior surfaces of both may be observed to incline slightly posterior of ver- tical. (The lateral portion of the anterior surface of each inclines anteriorly of vertical because a strong lateral process develops on each nasal and projects far anteriorly as part of the premaxillary crest.) 3) At the anterior margin of the synvertex the right premaxillary bone extends farther forward than does the lateral process of either nasal. MOORE: BEAKED WHALES 265 In Mesoplodon: 1) Where the anterior surfaces of the nasals ap- proach the synvertex of the skull, they are seen in dorsal view to be strongly concave (i.e., a horizontal plane would transect their com- bined surfaces in a concave arc, or U-shape, as in fig. 13) , and the most anterior projection of the nasals is near the lateral margin and on the lateral process of the right nasal. 2) In lateral view of the ascent of the nasals from the margin of the mesethmoid bone, the mesial por- tion of the anterior surfaces of the nasals inclines posteriorly from the vertical (and in some species does not reach the surface of the syn- vertex). 3) At the anterior margin of the synvertex one of the pre- maxillae (usually the right) ordinarily extends farther anterior than does either lateral process of the nasals. From the characters of the nasal bones alone an arrangement of genera from most primitive to most derivative would start with de- velopment of two branches: the first branch would have Berardius on it as the more primitive and Ziphius as the more derivative; the second branch would have Tasmacetus on it as the most primitive and Indopacetus, Mesoplodon, and Hyperoodon as successively more deriv- ative. Linearly, they can be arranged on a most primitive to most derivative scale as Berardius, Tasmacetus, Indopacetus, Ziphius, Hy- peroodon, and Mesoplodon, but the former reveals the evidence of relationships better. Berardius and Ziphius resemble each other in characters 1, 2, and 3, and Indopacetus, Hyperoodon, and Mesoplodon also resemble each other in characters 1, 2, and 3. But the primitive two genera differ fully from the derivative three genera in characters 1 and 3. Tasmacetus is nicely intermediate in character 1 between the primitive two and the derivative three of the other living genera, and Indopacetus is close to intermediate. Tasmacetus resembles the more derivative pair of genera in character 3. In a general way the nasal bones of Tasmacetus seem somewhat intermediate in morphol- ogy between the primitive two genera, and, especially in dorsal view, most nearly resemble those of Berardius. The characters of the nasals of Tasmacetus can certainly be said to permit development equally well in the direction of nasals like those of Ziphius or toward ones like those of Mesoplodon. Concordance with the related differences of the premaxillary crest among these genera, however, suggests another interpretation: that the nasals of Berardius are the more primitive, and that those of Tasmacetus have already evolved slightly away from that state toward the characters typified by Mesoplodon and Hyperoodon. 266 fieldiana: zoology, volume 53 Implications Regarding Relationships Presentation of so much detail in two principal lines of evidence in this investigation of relationships among the living genera of beaked whales has proceeded farther than was contemplated at its inception, and beyond what I would have planned without including study of the fossil record. It grew as research tends to grow, by lur- ing the student into exploring further lines of investigation that only become recognized as promising as the study proceeds. Now that exhaustion of time has drawn the line against further attractive pos- sible lines of investigation my hope is that enough evidence has in- deed been assembled and evaluated to establish the relationships of the living representatives of hyperoodontid phylogeny sufficiently to justify and stimulate a similar study of the fossils. Although consideration of the teeth and alveoli has, compared with that of other lines of evidence, proceeded to greater length here and has revealed much of potential systematic value, these lines of evidence do not emerge as the most satisfying indicators of general degree of relationship observable in good samples of these genera available for study as museum specimens (usually skulls — often with mandible missing, still more often with the teeth missing). There is, for example, the practical objection to the small sample and imperfect knowledge of teeth and alveoli of adults of either species of Hyperoo- don. While appreciation of taxonomic characteristics of the teeth and alveoli requires morphologically mature specimens, the taxonomic characters of the nasal bones and of the premaxillary crest described here, are well formed in immature specimens, which means that these characters have been observed, and are verifiable, in a much larger sample. The number and position of teeth, the size and shape of teeth, and what is known of their alveoli, would all conspire to make Ziphius and Hyperoodon more closely related to each other than either is to any other genus. This is strongly opposed by evidence described in the characters of the elevated syn vertex of the skull. In the charac- teristics of the nasal bones, Ziphius and Berardius more closely re- semble each other than either does any other genus. In the characters of the nasal bones, also, Hyperoodon and Mesoplodon resemble one another more than any other genus. Moreover, on the synvertex also, the characters of the premaxillary crest firmly support the evi- dence from the nasal bones of close relationship between Hyperoodon and Mesoplodon. The premaxillary crest of Ziphius resembles that of Berardius more than of any other living genus in being both narrow MOORE: BEAKED WHALES 267 and thin. The somewhat mesial orientation of the faces of the pre- maxillary crest, and also their erection to the vertical in Ziphius, in- dicate a separate line of development for Ziphius to a form clearly derivative; whereas the premaxillary crest of Berardius has remained exceedingly primitive. The long anterior development of the nasal bones of Ziphius may be said to support the evidence from the pre- maxillary crests of a more derivative condition of Ziphius than Berar- dius. (Also, characters 16 to 19 in the dendrogram may be considered four additional derivative ones of Ziphius, compared to which Ber- ardius has primitive alternatives.) In Flower's (1872) day, 65 years before Tasmacetus was discov- ered, drastic evolutionary reduction of the erupting teeth to only two pairs in one genus and a single pair in the other three living genera of beaked whales so strikingly distinguished the beaked whale super- family from the other living Cetacea that only a few scientists gave weight to the other characters thought to distinguish the beaked whales. Only 30 years ago the discovery of Tasmacetus with long rows of functional upper and lower teeth, suddenly removed that previously convenient character. Reconsideration of the characters distinguishing the living mem- bers of the superfamily from the remainder of the living Cetacea is outside of the scope of the present paper, but Fraser and Purves (1960, fig. 26) have recently contributed to knowledge of this super- family distinction. However, the characters they use for this are evidently too constant within the superfamily to help me in the pres- ent investigation. In looking over the 15 superfamilial characters enumerated by Flower (1872, p. 204) for ones of the skull which have survived the discovery of Tasmacetus, I found the especially elevated synvertex of the skull to be the most impressive of the remaining skull characters of the living superfamily. Constituted by exposures of the upturned edges of four paired bones and one unpaired, it seemed com- plex enough to be likely to offer reward for intensive and quantified taxonomic investigations. The above described and evaluated characteristics of the teeth and alveoli do not, for whatever reasons, now provide so convincing or coherent a basis for recognizing major phyletic divisions of the living genera of Hyperoodontidae as do the above described and eval- uated characters of the synvertex of the skull. The latter are there- fore employed with suitably primary emphasis in construction of the accompanying model (fig. 20) to depict, by interpretation of the above evidence, a hypothetical course of evolution which would ac- FIG. 20. DENDROGRAM OF HYPOTHETICAL EVOLUTION OF LIVING GENERA OF THE BEAKED WHALES 28 »ON( FILLING IN MISOROSTRAL CANAL LATE IN MATURATION. 27. FLATTENING AND OTHER SOCIALIZATION OF TMf TEETH. 26 DEIP AVEOLI IN ADULT MALES. {**• CHEAT ENLAIGEMENT OF MAXIUARr PROMINENCES. 24. THICKENING OF PHI MA XII L ARY CRESTS. 23 . PENETRATION OF PREMAXILLARY CREST IY ANTERIOR PROCESSES OF THE NASALS. 22 . DEPRESSION MESIALLY OF ANTERIOR AND DORSAL SURFACES OF NASAL RONES. TRENCHANT SUPRAORRITAL GROOVE OF 21. DEVELOPMENT OF THE MAXILLARY. !0 . REDUCTION OF THE POSTERIOR PROCESSES OF THE PREMAXILLARY CREST. 19. FURTHER WIDENING OF PREMAXILLARY CREST. 15. REDUCTION OF AREA OCCUPIED IY NASAL RONES ON VERTEX OF SKULL. 17. ELEVATION OF SUPRAOCCIPITAl TO THE VERTEX OF THE SKULL. 16. REDUCTION OF TEETH TO A SINGLE. APICAL. MANDIRULAR PAIR. { 11. RETENTION OF FULL COMPLEMENT OF UPPER AND LOWER TEETH. ^M. ELEVATION OF L_ 13 - MUD THICKEN POSTNARIAl PREMAXILLAE TO VERTICAL. ING AND WIDENING OF PREMAXILLARY CREST. I. ELEVATION OF NASALS AND PREMAXILLAE BEHIND THE NARES. 2. PROJECTION OF NASALS FARTHER FORWARD THAN PREMAXILLAE ON VERTEX. S. LATERAL COMPRESSION OF APICAL PAIR OF TEETH 4. elevation of postnarial premaxillae to vertical. 7. elevation of supraoccipital to vertex. • .turning inward and widening of anterior faces of premaxillary crests 9. proliferation of ione partially filling mesirostral Canal (esp. in males). 10. reduction of developed teeth to one pair (erupting only IN MALES). 11. RESORPTION OF RONE FORMING A PRENARIAL BASIN (ESP. IN MAIESL 12. DEVELOPMENT OF SEXUAL DIMORPHISM I IN 9, 10,11). Fig. 20. Distance from any one generic name to each other along the hypo- thetical lines connecting them indicates degree of relationship between the genera (e.g., Hyperoodon and Mesoplodon are the most closely related of living genera, Ziphius and Mesoplodon the most distantly). A dotted line extended up to the "present" from lineage A provides a base line of primitiveness in the family from which the relative direct distances to the living genera expresses derivativeness. 268 MOORE: BEAKED WHALES 269 count for the amount of observed difference among the six living genera. The dendrogram is turned 90° from normal position to accom- modate listing beside it the morphological characteristics basic to it. Each hypothetical lineage in Figure 20 from which at least one liv- ing genus is supposed to have derived is designated by a letter. Line- age A represents ancestors to all the living genera of beaked whales. It is presumed to have had: the nasal and premaxillary bones notably elevated behind the nares, and (by implication of nos. 2, 3, 4, 8, 13, 14, and 18) the nasal bones neither sunken back nor projecting forward mesially at their anteriormost margin on the syn- vertex; nasals occupying most of the area of the syn vertex; the pre- maxillae thin and narrow postnarially ; numerous cone-shaped, func- tional, teeth on maxillae and mandible; premaxillae not achieving a postnarial rise perpendicular to the long axis of the beak; and the postnarially up-curved ends of the premaxillae very slightly widened to form an incipient premaxillary crest. Lineage B is supposed to have differentiated in the following char- acteristics before giving rise to phyla C and D : the nasal bones pro- jecting anteriorly from their common middle at the anterior margin of the syn vertex; the maxillary teeth lost and the mandibular teeth reduced in number, perhaps to two apical pairs. Lineage E presumably evolved the following characters before giving rise to lineages F and G: elevation of the premaxillae posterior to the nares until in profile they attain an angle perpendicular to the long axis of the beak, and mild widening of the premaxillary crest. Lineage G, before proliferating phyla H and I, would have, as did B, experienced a great reduction in number of functional teeth; the supraoccipital would have, as in phylum C, risen approximately to the syn vertex of the skull; on the syn vertex of the skull the premaxil- laries would by thickening and widening have expanded the relative area of the synvertex occupied, leaving the nasals comparatively less. Lineage I, before giving rise to those two phyletic lines which have produced the living genera Hyperoodon and Mesoplodon, would have developed two new characteristics in the shape of the nasal bones: the middle of the common antero-dorsal surface of these paired, adjacent bones becomes recessed by a depression which is U-shaped in cross-section (fig. 13) and usually deepest at the meet- ing of the anterior and dorsal surfaces of these bones. This results in the lateral portion of each nasal bone being the part which reaches 270 FEILDIANA: ZOOLOGY, VOLUME 53 farthest forward on the synvertex of the skull, but this most forward- reaching part develops into an anterior process which penetrates the adjacent premaxilla and shares with it the form of the bipartite pre- maxillary crest (fig. 16). Characteristics Considered Convergent Several relatively derivative characteristics have, according to the hypothetical relationships depicted in Figure 20, been acquired in- dependently, sometimes by quite divergent lineages. From rela- tively primitive to derivative in the dendrogram these would be: Great reduction of number of teeth, in lineages B and G. Elevation of the profile of the premaxillae postnarially until at least perpendicular to the long axis of the beak, in phyla C and E. Elevation of the supraoccipital bone approximately to the syn- vertex of the skull, in lineages C and G. Proliferation of bone, from at least the vomer, tending to fill the mesorostral canal, and thus to stengthen the slender beak, in phyla C, F and K. Compression of the principal, or only, pair of well-developed teeth, in phyla D and K. Sexual dimorphism in the eruption and degree of development of a single pair of teeth, in phyla C and I. Sexual dimorphism in the degree of filling of the mesorostral canal in phyla C and K. None of the lines of evidence pursued in the present investigation happens to include clear reference to the extraordinary character which distinguishes Hyperoodon as a genus, and in the males of H. ampullatus reaches a morphological development which seems to me the most amazing in the superfamily. This is the development of the pair of common, maxillary prominences into massive, soaring superstructures. (It probably has to become familiar to be appre- ciated. To a student of cetology they rival the antlers of the fossil "Irish elk" in magnificence, but whale skulls are extraordinary in so many ways that the special grandeur of the maxillary crests of an old male H. ampullatus may be beyond the immediate grasp of the un- initiated.) Thus, Hyperoodon does have this one very distinctive specialization. It does not, even so, quite equal Mesoplodon in de- rivative characteristics in all the lines of evidence studied, and par- MOORE: BEAKED WHALES 271 ticularly, of course, in the dentition which seems especially important at the generic level in beaked whales (but also at infrageneric levels), as indicated in characters 8, 9, and 10 with the dendrogram. DISCUSSION OF CLASSIFICATION Inasmuch as Simpson (1945, p. 215) wrote almost regretfully of having accorded the beaked whales only familial status instead of superfamilial, and since Fraser and Purves (1960, fig. 26) raised them to superfamily rank, use of the superfamily category is fol- lowed here. The dendrogram illustrates the relationships between the two major divisions of the genera of Hyperoodontoidea, and tribal rank for these in classification is required to acknowledge the differences between them so that there will still be a lower suprageneric category to express the much greater differences between Tasmacetus or Indo- pacetus and either Hyperoodon or Mesoplodon than exist between the latter two. The tribes Hyperoodontini to include Tasmacetus, Indo- pacetus, Hyperoodon, and Mesoplodon; and Ziphiini to include Berar- dius and Ziphius, do permit the other differences that are greater than generic to be expressed with subtribal rank, and this is done. Simpson (1945, p. 215) in his most recent classification of the mammals followed principally Kellogg (1928) in his arrangement of the beaked whale genera, which of course contains the fossil ones, but concluded that no satisfying arrangement of the genera within the family had yet been achieved. Fraser and Purves (1960, p. 40) whose intensive research on the living Cetacea included Berardius (2 species), Ziphius (1), Hyperoodon (1), and Mesoplodon (1) as their sample of the beaked whales, found the sample to be remarkable among the Cetacea as a whole because there was a "general homo- geneity ... of structure in this region [the basicranial region affected by specialization for underwater hearing] in all the ziphioids, there being little or no evidence of progressive changes between individual [genera]." It is true that Scheffer and Rice (1963) and Hershkovitz (1966, p. v) offer compilations with arrangements of those genera which they doubtless hope to be natural. It is also correct that both arrangements recognized Tasmacetus as especially primitive and Hy- peroodon as much more derivative, but there is no other concordance with the present findings nor, of course, any evidence offered that justifies those arrangements of the taxa. Thus, no previous student 272 Fig. 21. Hyperoodon (Hyperoodon) ampullatus, FMNH 15553, front view, sighted between maxillary crests (a), with long axis of beak horizontal, camera leveled and with center of lens at height of summit of mesethmoid bone (b), reveal- ing how even in this very immature specimen the maxillary prominences are crests soaring above the mesethmoid bone. Premaxillary bones (c) and nasal bones (d) also shown. 273 274 FIELDIANA: ZOOLOGY, VOLUME 53 of cetacean systematics has from original research offered a classifi- cation of the living genera of beaked whales with which the present offering needs to be reconciled. A very real gap in knowledge of relationships among living genera therefore exists which the present paper seeks to fill. In the above analysis of "Relationships Among the Genera" there was little need to deal with infrageneric categories except in species of Mesoplodon, but the species Hyperoodon planifrons and H. ampul- latus are so exceedingly distinct from one another in the very char- acter that most distinguishes them both from other genera, the enor- mous enlargement of the maxillary prominences, that subgeneric distinction is appropriate. Since ampullatus is the type species of the genus and no generic or subgeneric name has been proposed for H. planifrons, a new subgeneric name is proposed. Frasercetus new subgenus Type species. — Hyperoodon planifrons Flower, 1882. The maxil- lary prominences in Frasercetus, although massive, are low, spread- ing, and do not rise to the height (above the long axis of the beak) of the vertex of the skull. In subgenus Hyperoodon the maxillary prominences stand erect as great crests even in immatures (fig. 21), and in adult males rise high above the synvertex of the skull (Gray, 1846, pi. 4). The new name recognizes Dr. F. C. Fraser of the British Museum for his many contributions to our knowledge of beaked whales, and other Cetacea, several references to which should be found in the literature cited. Scheffer and Rice (1963, p. 8) placed several big-toothed species in the subgenus Dioplodon, but unpublished plots of my measure- ments of teeth of more than 80 adults of 11 species of Mesoplodon show no adequate basis in the size of teeth for breaking up the species of Mesoplodon into a large-toothed subgenus and a small-toothed one. Size of teeth among species of Mesoplodon being therefore an irrele- vant continuum one must abandon it, and classify the species in- stead in a most-primitive-to-most-derivative progression on the char- acteristics (described in detail above) : 1) distance of alveolus from apex of mandible; 2) anteriorly inclining, erect, and posteriorly inclin- ing posture of tooth; and 3) orientation of the denticle on the tooth. Wljile there is, in the evidence available to me, no break or gap in tooth size sufficient to warrant separation into a subgenus of sev- MOORE: BEAKED WHALES 275 eral species with big teeth, and another of several with little, two species of Mesoplodon are individually regarded as subgenerically dis- tinct in morphological characters as follows: extraordinary width and depth of the jaw especially, but the teeth somewhat massive also, in densirostris; the exceedingly derivative character of the teeth in lay- ardi as described above. Names Dolichodon and Dioplodon, respec- tively, are available and employed. For synonymies and detailed records of distributions with cita- tions, see Hershkovitz (1966, pp. 122-149). CLASSIFICATION OF THE LIVING GENERA OF BEAKED WHALES Order Cetacea Brisson, 1762, pp. 3, 227 (=Cete Linnaeus, 1758, p. 75). Whales, porpoises, dolphins. Suborder Odontoceti Flower, 1867, pp. 110, 115. Toothed whales. Superfamily Hyperoodontoidea, new name. Beaked whales. Family Hyperoodontidae Gray, 1866, p. 62. Beaked whales. Tribe Ziphiini, new form? Subtribe Berardiina, new form. Four-toothed whales. Genus Berardius Duvernoy, 1851. Species Berardius arnuxi Duvernoy, 1851. Southern four-toothed whale. Temperate waters of the south- ern hemisphere. Berardius bairdi Stejneger, 1883. Northern four-toothed whale. North Pacific temperate waters. Subtribe Ziphiina Gray, 1850, pp. 56, 61 (greatly restricted). Goose-beaked whales. Genus Ziphius G. Cuvier, 1823. Species Ziphius cavirostris G. Cuvier, 1823. Goose-beaked whale. Warm and temperate waters of the world (provisionally charted by Moore, 1963a). Tribe Hyperoodontini, new form. Subtribe Tasmacetina, new form. Genus Tasmacetus Oliver, 1937. Tasman whale. Species Tasmacetus shepherdi Oliver, 1937. Tasman whale. New Zealand waters. 276 MOORE: BEAKED WHALES 277 Subtribe Genus Species Subtribe Genus Subgenus Species Subgenus Species Genus Subgenus Species Indopacetina, new form. Indopacetus, new genus. Indopacetus pacificus Longman, 1926. Indo-Pacific whale. Hyperoodontina, Gray, 1846, part. Hyperoodon Lacepede, 1804. Bottle- nosed whales. Hyperoodon Lacepede, 1804. Hyperoodon ampullatus Forster, 1770. Northern bottle-nosed whale. Very northern North Atlantic. Frasercetus, new subgenus. Hyperoodon planifrons Flower, 1882. Southern bottle-nosed whale. South temperate and southern subtropical waters. Mesoplodon Gervais, 1850. Deep-sock- eted whales. Mesoplodon Gervais, 1850. Mesoplodon hectori Gray, 1871. Southern hemisphere temper- ate waters. M. mirus True, 1913. Predomi- nantly northern North Atlan- tic (charted by Moore, 1966) . M . europaeus Gervais, 1855. Antil- lean beaked whale. Southern North Atlantic (charted by Moore, 1966). M. ginkgodens Nishiwaki and Ka- miya, 1958. Ginko-toothed whale. Southern North Pa- cific and Indian Ocean (see Moore and Gilmore, 1965). M. grayi von Haast, 1876. Scam- perdown whale. Southern hem- isphere temperate waters. 278 FIELDIANA: ZOOLOGY, VOLUME 53 M. carlhubbsi Moore, 1963. Arch- beaked whale. North Pacific waters (charted by Moore, 1963b). M. bowdoini Andrews, 1908. Deep- crested whale. Southwest Pa- cific and Indian Ocean. M. stejnegeri True, 1885. Bering Sea beaked whale. Northern North Pacific (charted by Moore, 1963b). M. bidens Sowerby, 1804. North Sea beaked whale. Northeast- ern North Atlantic (charted by Moore, 1966). Subgenus Dolichodon Gray, 1871. Species M. layardi Gray, 1865. Strap- toothed whale. Southern hem- isphere temperate waters. Subgenus Dioplodon Gervais, 1850. Species M. densirostris Blainville, 1817. Dense-beaked whale. Tropical and warm waters of the world (discussed by Moore, 1966). Characters of Suprageneric Tax a The tribe Ziphiini, as is obvious in the above classification, in- cludes genera Berardius and Ziphius, and in the dendrogram, Fig- ure 20, hypothetical phyla B, C, and D. Its unifying and diagnostic characters as presently known from only the living genera are that the nasal bones project farther anteriorly from the syn vertex than do the premaxillae (see figs. 15 and 19), and the posterior up-turned ends of the premaxillae are thin. The subtribe Berardiina as pres- ently known contains only the living genus Berardius and will thus have the same diagnosis, given below. The tribe Hyperoodontini includes the known members of living genera Tasmacetus, Indopacetus, Hyperoodon, and Mesoplodon, and in Figure 20 the hypothetical lineages E, F, G, H, I, J, and K. Its distinctive characters are definitely widened and thickened postnarial MOORE: BEAKED WHALES 279 premaxillae, and projection of these anteriorly from the synvertex of the skull beyond the nasals (see figs. 13, 16, and 17). Subtribe Tas- macetina thus far contains only the living member of the genus Tasmacetus, and so has the same diagnosis, given below. Subtribe Indopacetina contains only the known living member of the genus Indopacetus, and so shares its diagnosis, given below. Subtribe Hy- peroodontina includes all of the 13 known living species of Hypero- odon and Mesoplodon, and in the dendrogram the hypothetical line- ages I, J, and K. This subtribe is characterized by a depression (U-shaped in cross-section) of the middle of the antero-dorsal surface of the combined nasals which permits the antero-lateral part of each nasal bone (but especially the right one) to project farther anteriorly than does the mesial part (see figs. 13 and 16). GENERIC DIAGNOSES Berardius Duvernoy, 1851, the four-toothed whales Characteristics 1. In adults of both sexes (Omura, et al., 1955, pp. 107, 108) there are two pairs of well-developed teeth, the larger pair at the apex of the mandible, a smaller pair a decimeter or two posterior to the first; the tips of both pairs protrude through the gum, and at least the anterior pair sustain wear. (Kirino, 1956, shows that 84.6 per cent of a sample of 65 adults of bairdi had only two pairs, none had less, and only 3.1 per cent had more than a single supernumerary tooth.) This character distinguishes Berardius from all other living genera of Cetacea. See Figure 22. 2. When the skull is upright and the long axis of the beak is hori- zontal, viewed laterally the dorsal profile of the premaxillary bones does not reach (in its posterior ascent) or even approximate, vertical. See Figure 14. 3. The suture between the maxillary and premaxillary bones does not fuse for more than 20 per cent of its length on the dorso- lateral surface of the beak. (The suture was partly closed by fusion of these bones in only one instance, on both sides for about 10 per cent of the suture's length on the beak, and at the anterior end.) 4. When the skull is viewed from posteriorly on a line with the long axis of the beak, the synvertex (constituted in this genus by the dorsal surfaces of the nasal bones and ends of the premaxillaries) rises above the supraoccipital bone like a slightly domed cupola with sheer sides. (Tasmacetus is similar from this view, but its synvertex is flat or depressed instead of slightly dome-shaped.) By the characters enumerated above, the sample of 31 skulls of Berardius is distinguished from the examined samples of the other living genera of beaked whales as follows: Ziphius by characters 1, 2, 3, and 4; Tasmacetus by numbers 1, 2, and 3; Indopacetus by 1, 2, 3, and 4; Hyperoodon by 1, 2, 3, and 4; and Mesoplodon by 1, 2, 3, and 4. 280 MOORE: BEAKED WHALES 281 Fig. 22. Teeth of Berardius bairdi, adult c? 33 feet long (Pike, 1953), showing relative size of one of the larger, apical pair (which are triangular and laterally compressed) and one of the cone-shaped subapical pair. Larger tooth is 89 by 103 mm. Courtesy of Gordon C. Pike. Ziphius Cuvier, 1823, the goose-beaked whale Diagnosis 1. Where the premaxillary bones ascend posteriorly on either side of the superior nares and terminate, their anterior faces are ori- ented mesially a small but obvious amount from directly forward. See Figure 15. 2. The combined breadth of the nasal bones is greatest anteriorly and where the right nasal is out of contact with the right premaxillary bone. See Figure 15. 3. When the skull is upright and the long axis of the beak is hori- zontal, in lateral view the nasal bones both project somewhat farther anteriorly from the synvertex of the skull than do the up-curled pos- terior ends of the premaxillary bones. See Figure 15. By all three of the characters enumerated above the 50 specimens of Ziphius examined differ from the cited samples of Berardius, Tas- macetus, Indopacetus, Hyperoodon, and Mesoplodon. Tasmacetus Oliver, 1937, the Tasman whale Characteristics 1. There is a row of functional maxillary teeth, numbering 21 or 22 to a side and measuring 15 to 27 mm. in length, 5 to 13 mm. wide 282 FIELDIANA: ZOOLOGY, VOLUME 53 (in the two specimens), and a long row of functional mandibular teeth, numbering 25 to 27 on a side (in the three specimens). Ante- rior to the mandibular tooth rows, and separated from them on each side by a diastema 25 to 45 mm. long, is a pair of larger teeth at the apex of the mandible. 2. The greatest transverse breadth of the nasal bones on the syn- vertex of the skull exceeds the greatest transverse breadth of the right portion of the premaxillary crest. See Figure 17. 3. The greatest length of the posterior process of the right part of the premaxillary crest exceeds the remaining anteroposterior thick- ness of the crest; and the greatest length of the left one exceeds the remaining anteroposterior thickness of the left part. 4. When the long axis of the beak is horizontal, the supraoccipi- tal is so low that if the skull is viewed from 2 or 3 m. on a line with the long axis of the beak, the widest part of the premaxillary crest stands above the profile of the braincase. Diagnosis By the characters enumerated above, Tasmacetus is distinguished from other living beaked whale genera as follows: from Berardius by 1 and 3; Ziphius by 1, 2, and 4; Indopacetus by 1, 2, 3, and 4; Hy- per oodon by 1, 2, and 4; and Mesoplodon by 1, 2, and 4. Indopacetus Moore, 1968, Indo-Pacific whale Characteristics 1. The alveoli of the developed teeth are a single pair, apical on the mandible, and in an old adult male become progressively at least as shallow as 30 mm. 2. The frontal bones occupy an area of the syn vertex of the skull approximating or exceeding that occupied by the nasal bones. 3. There is almost no posterior process of the premaxillary crest extending posteriorly on the synvertex between the nasal and maxil- lary bones, or between the frontal and maxillary bones. 4. In the lateral extension of the maxillary bone over the orbit there is a deep groove about half as long as the orbit. 5. At about the midlength of the beak there is a swelling caused by the lateral margins proceeding forward a short distance without convergence (in the Danane whale) or even with a little divergence (in the MacKay whale), then convergence again. MOORE: BEAKED WHALES 283 Diagnosis Indopacetus is distinguished by the characters enumerated above from the other living genera of beaked whales as follows: Berardius by nos. 1, 2, 3, 4, and 5; Ziphius by 2, 3, 4, and 5; Tasmacetus by 1, 2, 3, 4, and 5; Hyperoodon by 2, 3, 4, and 5; and Mesoplodon by 1, 3, 4, and 5. Hyperoodon Lacepede, 1804, the bottle-nosed whale Diagnosis 1. When the skull is upright and the long axis of the anterior half of the beak is horizontal, a horizontal plane transecting the summit of either maxillary prominence passes well above the mesethmoid bone. See Figure 21. This distinguishes all 25 specimens of Hyperoodon from all of the above specimens studied of the other living genera of beaked whales. 2. The greatest length of the largest maxillary foramen exceeds the least distance between the paired premaxillary foramina in the same individual. This distinguishes all^25 specimens of Hyperoodon from all the other specimens studied of other genera of beaked whales as listed above (except one unusual individual out of 32 Mesoplodon layardi) . The specimens of Hyperoodon studied consisted of 21 H. ampul- latus and four H. planifrons. Mesoplodon Gervais, 1850, deep-socketed whales Characteristics 1. The alveoli of aging males remain deep, in many species con- tinuing to contain about half the length of the tooth, and in all spe- cies probably exceeding 30 mm. in depth. (This distinguishes all adult males of Mesoplodon examined as follows : mirus, 2 ; europaeus, 3 ; ginkgodens, 2 ; grayi, 6 ; carlhubbsi, 4 ; bowdoini, 4 ; stejnegeri, 3 ; bidens, 15; layardi, 6; and densirostris, 8. No adult male is yet known of M. hectori.) 2. The single pair of teeth of any adult Mesoplodon is so com- pressed transversely that the greatest diameter of the tooth perpen- dicular to the long axis of the tooth is at least 1.66 of the greatest transverse thickness of the tooth (which would be perpendicular to both the long axis and the axis of the preceding, anteroposterior dimension). 284 FIELDIANA: ZOOLOGY, VOLUME 53 3. The suture between the maxillary and premaxillary bones fuses in adults for more than 50 per cent of its length on the dorso- lateral surface of the beak. S. 4. In posterior view on a line with the long axis of-^he beak, the supraoccipital occludes the synvertex of the skull so much that sheer sides may not be seen on both sides of the premaxillary crest. 5. The anterior faces of the premaxillary bones rising beside and behind the superior nares, are both oriented anterolateral^ or ante- riorly, but not anteromesially. 6. The right nasal bone remains in contact with the right pre- maxillary bone anteriorly where the breadth of the combined nasals is greatest. 7. When the skull is upright with the long axis of the beak hori- zontal, and is viewed laterally, the premaxillary bones are seen to project anteriorly from the vertex of the skull farther than the nasal bones (comparing right premaxillary with right nasal, and left with left). 8. When the skull is upright with the long axis of the beak hori- zontal, a horizontal plane transecting the summit of either maxillary prominence passes well above the mesethmoid bone. 9. The least distance between the pair of premaxillary foramina exceeds the greatest length of the larger maxillary foramen in the same individual. (This distinguishes 184 of the 185 individuals of Mesoplodon here reported, the exception being one of the 32 M. layardi.) Diagnosis The genus Mesoplodon is distinguished from other living genera of beaked whales by the above-numbered characteristics as follows: from Tasmacetus by number 1; Berardius by 1, 2, 3, and 4; Ziphius by 5, 6, and 7; Indopacetus by 1 and 2; and from Hyperoodon by 8 and 9. KEYS FOR IDENTIFICATION OF THE LIVING GENERA OF BEAKED WHALES Several authors have published keys for identifying the genera of beaked whales of a particular part of the world, a recent example being that of McCann (1962a). Despite its broad title, "Key to the family Ziphiidae, beaked whales," this example proceeds to limit itself to species of living beaked whales then known to occur in New Zealand waters. This excludes the seven species of Hyperoodon, Berardius, and Mesoplodon known only to occur in the northern hemisphere. It also excludes Mesoplodon hectori, I. pacificus, and M . densirostris, the first two for reasons quoted, and I think invali- dated, above, and M. densirostris, presumably because it is not known from New Zealand waters. M. densirostris has been known from Lord Howe Island for almost a century (Krefft, 1870), 700 miles west but hardly 3° north of New Zealand. The likelihood that this omis- sion of densirostris as potentially a part of the New Zealand marine fauna will vitiate McCann's key to the local species of Mesoplodon, has now been emphasized by the occurrence of densirostris 9° of lati- tude farther south on a Tasmanian beach (Guiler, 1966), and by the implications assembled by Moore (1966, pp. 50-51) that M. densi- rostris may occupy habitat farther off-shore than do other species of Mesoplodon. The following keys do propose to distinguish, one key by charac- ters of the skull, the other by those of the teeth, all presently known living species of all these genera to the level of genus. Beaked Whales in the Flesh A whale examined in the flesh belongs to the beaked whale family if it: 1) is a small whale (from 4.3 - 12.8 m. long for adults); 2) has no notch dividing the caudal fin conspicuously into right and left flukes; 3) possesses a pair of natural grooves on the throat, conver- gent anteriorly but not connected; 4) has the rostrum narrow and produced anteriorly like a dolphin's beak; and 5) lacks plates of baleen (protruding down from the upper jaw with which to sieve 285 286 FIELDIANA: ZOOLOGY, VOLUME 53 small food from sea water taken into the mouth). Exceptions or modifications have been reported for items 2 and 3. Although the species Mesoplodon hectori was discovere^and made known to science almost 100 years ago, and was the fifth of 11 living species now of Mesoplodon to be described, the first adult specimen, as of this writing, has just been reported upon (Guiler, 1967). As Indopacetus pacificus is still known from but two skulls, the character of its external appearance remains to be discovered. Sets of comparable external measurements of adults of Ziphius cavirostris and even for Hyperoodon ampullatus, as well as the rarely seen H. planifrons, are not available in the literature in sufficient number to permit construction of a key to the genera in the flesh. Part of the trouble results from each person making only a few meas- urements, and different persons making different ones. A suggested standard has been offered (Norris, 1961) and use of it by all of us should in time advance us to a state of knowledge in which a key can be constructed to identify beaked whales in the flesh. Publication of just a total length of a specimen unqualified by a statement such as "measured personally in a straight line with tape" or "paced off" or "fisherman's estimate," results in seemingly scientific records of Ziph- ius cavirostris 7.6 and 8.56 m. long (Cabot, 1965, and Stephen, 1932, for example) which there is increasing reason to doubt as sets of measurements made with evident care by the naturalist or zoologist himself are showing no specimen longer than 6.58 m. (Kenyon, 1961, for example). If there are rows of functional teeth on upper and lower jaws, but at the apex of the lower jaw there is a pair larger than any other and separated from the others by a gap larger than normal between the other teeth, it is Tasmacetus. If it has only four teeth near the apex of the lower jaw, the genus is Berardius. If it has only two flat (later- ally compressed) teeth rising out of the lower jaw at some distance back from the apex of the jaw, it is a male of some species of Meso- plodon. If it has no teeth showing above the gum, it is either an im- mature or an adult female. To go beyond this, it is necessary to use the key to the teeth. The best thing to do to be certain of identifying it, and of having a specimen in case it is of a rare species, is to carefully remove the head (with a sharp knife, never an ax or anything striking blows) and to mascerate it. This is best done for the smaller species in a 50- gallon steel drum located where the odor will disturb no one and dogs or other animals cannot get to it. Masceration may alternatively be Fig. 23. Skull of Berardius arnuxi, posterior view. The elevated synvertex stands above the low supraoccipital showing sheer sides. The synvertex is slightly domed. Bones and bony features: left maxillary prominence (a), left maxillary (b), left nasal (c), divided left frontal (d), supraoccipital (e). Fig. 24. Skull of Ziphius cavirostris, FMNH 99362, posterior view, on line with long axis of beak, illustrating how in the genera Hyperoodon, Mesoplodon, and Ziphius the high supraoccipital bone (a) shields the sheer sides of the elevated synvertex from posterior view. Compare with Figures 17 and 23. 287 288 FIELDIANA: ZOOLOGY, VOLUME 53 accomplished by burial in the beach sand for several months some distance beyond high tide mark. The great risks one takeswith this method are: 1) inability to devise a means of marking exajctly where it is buried so that someone else will not remove the marker for an- other use; 2) likelihood that a storm will cut away that part of the beach, removing and losing the skull; 3) likelihood that the important teeth and earbones will be lost upon otherwise successful excavation of the cleaned skull. KEY TO THE LIVING GENERA OF THE BEAKED WHALES BY CHARACTERS OF THE SKULL (Applicable to adults, and probably most immatures 1 ) la. On the syn vertex of the skull it is a nasal bone that extends farthest forward (as in Figs. 15 and 19) 2 (tribe ziphiini) b. On the synvertex of the skull it is a premaxillary bone that extends farthest forward (as in Figs. 13 and 16) 3 (tribe hyperoodontini) 2a. When the posterior aspect of the skull is viewed from a point aligned with the long axis of the rostrum, and from a distance of at least two meters, the profile of the synvertex projects above the supraoccipital as a slightly asymmetrical block with sheer sides (see Fig. 23) Berardius b. When the skull is so viewed, the synvertex of it is completely occluded by the supraoccipital, or so little of the synvertex shows that the profiles of both descending sides are not seen to become sheer (see Fig. 24) Ziphius 3a. A sulcus running along the middle of the combined surfaces of the pair of nasal bones, so depresses their combined middle anterodorsally that it is the lateral portion of each nasal bone which reaches farthest forward on the synvertex (see Figs. 13 and 16) 5 (subtribe Hyperoodontina) b. No such sulcus exists in the nasals (see Fig. 17) 4 4a. The area of the synvertex of the skull occupied by the nasal bones far exceeds that occupied by the frontals (see Fig. 17) Tasmacetus b. The area of the synvertex of the skull occupied by the nasal bones is less than or approximates that of the frontals Indopacetus 5a. When the skull is upright and the long axis of the rostrum is horizontal, a horizontal plane touching the summit of the higher maxillary prominence (= crest), passes well above the mesethmoid bone (see Fig. 21) . . .Hyper -oodon b. When the skull is so oriented, a horizontal plane touching the summit of both (or the higher) of the maxillary prominences transects the mesethmoid bone (see Moore, 1966, figs. 6, 7) Mesoplodon 1 By immatures in this instance I mean postnatal individuals with teeth not yet closed at the bottom, or with sutures of epiphyses on long bones or vertebrae not obliterated. KEY TO THE LIVING GENERA OF BEAKED WHALES BY CHARACTERS OF THE TEETH OF ADULTS la. Some 20-27 well-developed teeth erupt on each side of the upper and lower jaws, each characteristically at least 15 mm. long and 5 mm. wide, and be- come worn Tasmacetus MOORE: BEAKED WHALES 289 b. No teeth of such size become exposed through the gum, or no more than about four and restricted to lower jaw 2 2a. There are four well-developed teeth exposed through the gum close to the apex of the lower jaw (a larger apical pair and a smaller postapical pair, see Fig. 22) Berardius b. There are no teeth erupted (as large as 15 by 5 mm.), or the number of such teeth is limited to two mandibular ones 3 3a. The two well-developed teeth (erupted, or cryptic beneath the gum) are com- pressed so that the greatest anteroposterior diameter of either tooth (perpen- dicular to the long axis of the tooth) is at least 1.66 of the greatest transverse diameter Mesoplodon b. The two well-developed teeth are substantially less flattened (i.e., more nearly round in cross-section) 4 4a. The two well-developed teeth are erupted and subject to wear in life ( d" d") . 5 b. The two well-developed teeth do not erupt and wear (9 9) 6 5a. The shape given the apex of the tooth by wear is fairly symmetrical and nipple- like (see Hale, 1931, fig. 11), suggesting that the central core of the tooth is harder than the peripheral parts (N=l) d* Hyperoodon (planifrons) b. The shape of the worn surface is often strongly asymmetrical and not at all mammilate 7 6a. The cementum seems to invest the tooth only to within about a centimeter of the apex leaving exposed a slender, conical apex of dentine all around the base of which the cementum of the tooth immediately bulges (N = l, see McCann, 1961, pi. 3) 9 Hyperoodon (planifrons) b. The diameter of the tooth increases quite gradually below the slender, conical, dentine cap of the apex 8 7a. The shape of the tooth is bulbous at the base but then becomes concave in profile as the girth of the tooth diminishes rapidly, then less rapidly, resulting in a delicately sinuous profile, as illustrated in Figures 5, 6, and 7. Its surface becomes wrinkled upon approach of adulthood. The wear, as illustrated in Figures 6 and 7, may be strongly oblique, the wear surface facing anterolater- al^ and upward d" Hyperoodon (ampullatus) b. The shape of the tooth is not bulbous at the base, and no concave profiles are normally formed by its growth and wear, and the cementum surface does not become wrinkled; the natural shape varies from that of a spindle in early adult- hood almost to that of an egg at greater age. See Figure 5 lower right or con- sult Fraser (1942, pi. II, figs, f, g, h) d" Ziphius 8a. The shape is basically conical, although the long axis bends dorsad; accretion at the base of the cone makes it somewhat bulbous there, and the surface of this becomes wrinkled (see Figs. 4 and 5); the ratio of greatest length of tooth to greatest transverse diameter exceeds 0.35 (subadult) 9 Hyperoodon (ampullatus) b. The basic shape is of a spindle, although gently bent dorsad and truncated proximally, and is illustrated in Figures 1, 5 lower left and lower middle, and 8 left; the ratio of greatest length to greatest transverse diameter is less than 0.32 9 Ziphius ACKNOWLEDGEMENTS The persons listed in the section on "Materials" were considerate of my investigation and gave generously of their time toward seeing its needs met. In many of the institutions skulls were taken off exhibit for me to study. Dr. Fraser made sketches and measurements for me of the tooth and alveolus of a large male Hyperoodon on exhibit in the British Museum, and Miss King lent me British Museum specimens of Hyperoodon teeth. Dr. Clarke of the Royal Scottish Museum lent me a series of teeth of Scottish specimens Hyperoodon and Ziphius cavirostris. Mr. Bartholomai kindly provided me by letter of Jan- uary 20, 1965, the two special measurements of the alveoli and two of the beak of I. pacificus which are cited here. Dr. Guiler shipped me a specimen on loan from Tasmania to Chicago; Drs. Shotwell, Benson, and Rowinski, as well as Francis Fay and Aryan Roest, have each also shipped me on loan a skull of Mesoplodon. Mr. Donald S. Erdman has shipped me two skulls of Ziphius from Puerto Rico as a donation. It is a pleasure to acknowledge here this important and generous help. The National Science Foundation supported three study trips to North American coastal museums and the circumglobal study trip to other above museums by research grant GB 507 for a revision of the genus Mesoplodon, of which most of the present paper is a fringe benefit. Photographs for Figures 12, 15, 16, 21, and 24 were made by Mr. Homer Holdren and Mr. John Bayalis, staff photographers of the Field Museum; staff artists Miss Marion Pahl prepared Figures 6 and 11, and Walter Boyer, Figure 20, for publication, and Dr. Tibor Pe- renyi lettered Figures 1, 7, 8, 13, 15, 16, 17, 19, 21, 23, and 24. Dr. Maria Luisa Azzaroli provided the photographs of the second known specimen of Mesoplodon [now Indopacetus] pacificus enabling me to establish the proper relationships of this previously rather puz- zling species. My wife, Evelyn Lannert Moore, and successive secretarial assist- ants Jane Davis, Karen Gasche, Helaine Minkus, and Betty Peyton 290 MOORE: BEAKED WHALES 291 have helped attain the degree of perfectionism with details achieved here. An able student summer assistant of 1966, Pamela Rich, helped with combing the literature. SUMMARY This paper is an outgrowth of an intensive revisionary study of the genus Mesoplodon which, after preliminary study of materials in North American museums (Moore, 1966), extended to collections on other continents. The most direct, and hence the best quantified, results in this present paper from the study of 292 skulls of beaked whales in 40 institutions, are the diagnoses of the genera, for it was to construct these that the observations presented in them were tabu- lated. From these, two dichotomous keys to the genera are derived, one by characters of the skull and one by those of the teeth. The distinctions between the living genera of beaked whales, Hyperoodontoidea, had not been re-examined since the fifth living genus was discovered only 30 years ago, and the relationships be- tween the living genera have never been investigated in a way that revealed sufficient evidence to provide a satisfying classification with- in the superfamily. With such a goal in mind I have here compared the genera as represented by 292 skulls of the 18 living species in two major lines of evidence, dentition and morphology of the ele- vated syn vertex of the skull. Separate comparisons and evaluation of the implications are of- fered here of: 1) the number and position of the teeth, 2) the size and shape of teeth, 3) the structure of the alveoli, 4) the morphology of the premaxillary crest, and 5) the shape of the nasals. All of these lines of evidence provide some information critical in assessing relationships, but those of the elevated synvertex, nos. 4 and 5, indi- cate the most inclusive groups. Using the morphological characters drawn from these five sources, a hypothetical phylogeny is con- structed and presented as a dendrogram (Fig. 20) and a classifica- tion is offered based upon the postulated phylogeny. New categories are recognized: tribes Ziphiini, including the gen- era Berardius and Ziphius; and Hyperoodontini, including genera Tasmacetus, Indopacetus, Hyperoodon, and Mesoplodon; subtribes Berardiina and Ziphiina to contain their respective genera Berardius and Ziphius, because they have diverged from each other more mark- edly than generic degree of difference but less than tribal degree; 292 MOORE: BEAKED WHALES 293 Tasmacetina, to include Tasmacetus and to indicate the greater than generic but less than tribal differences between it and Hyperoodontina which includes the genera Hyperoodon and Mesoplodon. The two species of Hyperoodon are elevated to subgeneric level, and the new name required for this is Hyperoodon (Frasercetus) planifrons. A preliminary classification of the species of Mesoplodon is pre- sented, derived from relationships between number, position, and morphology of the teeth, and recognizing monotypic subgeneric stat- us for two. The species pacificus is removed from the genus Meso- plodon and elevated to generic rank, Indopacetus, new name, with subtribal status to indicate the degree of its distinction from the polytypic Hyperoodontina. LITERATURE CITED Andrews, R. C. 1908. Description of a new species of Mesoplodon from Canterbury Province, New Zealand. Bull. Am. Mus. Nat. Hist., 24(13), pp. 203-215, 5 figs., 1 pi. BOSCHMA, H. 1950. Maxillary teeth in specimens of Hyperoodon rostratus (Muller) and Meso- plodon grayi von Haast stranded on the Dutch coasts. Proc. Koninklijke Nederlandse Akad. van Wetenschappen, 53(6), pp. 3-14, 4 pis., 3 figs. Brazenor, C. W. 1933. First record of a beaked whale {Mesoplodon grayi) from Victoria. Proc. Roy. Soc. Victoria, 45(1), pp. 23-24, pi. 1. Cabot, D. 1965. Cuvier's whale, Ziphius cavirostris, on Achill Island, County May. Irish Natur. Jour., 15(3), pp. 72-73. Davies, J. L. 1963. The antitropical factor in cetacean speciation. Evolution, 17(1), pp. 107- 116, 2 figs. Erdman, Donald S. 1962. Stranding of a beaked whale, Ziphius cavirostris Cuvier, on the south coast of Puerto Rico. Jour. Mammal., 43(2), pp. 276-277. Flower, W. H. 1872. On the recent ziphioid whales, with a description of the skeleton of Berar- dius arnouxi. Trans. Zool. Soc. London, 8(6), pp. 203-234, pis. 27-29. 1878. A further contribution to the knowledge of the existing ziphioid whales. Genus Mesoplodon. Trans. Zool. Soc. London, 10, pp. 415-437. Forbes, H. O. 1893. Observations on the development of the rostrum in the cetacean genus Mesoplodon, with remarks on some of the species. Proc. Zool. Soc. London, 1893, pp. 216-236, pis. 12-15, 2 figs. Fraser, F. C. 1934. Report on Cetacea stranded on the British coasts from 1927 to 1932. Brit. Mus. (Nat. Hist.), Rept. No. 11, pp. 31-32. 1942. The mesorostral ossification of Ziphius cavirostris. Proc. Zool. Soc. Lon- don, (B), 112, pp. 21-30, pi. 3. 1945. On a specimen of the southern bottle-nosed whale, Hyperoodon planifrons. Discovery Reports, Cambridge, 23, pp. 19-36, 11 figs. 1946. Report on Cetacea stranded on the British coasts from 1933 to 1937. Brit. Mus. (Nat. Hist.), No. 12, pp. 1-56, 11 figs. 1949. Whales and dolphins. Pp. 201-360. In Norman, J. R. and Fraser, F. C, Fieldbook of giant fishes, whales and dolphins. G. P. Putnam's Sons, New York. Pp. xxii+360, 8 color plates, 97 numbered text figs. 1950. Note on the skull of Hector's beaked whale, Mesoplodon hectori (Gray), from the Falkland Islands. Proc. Linnean Soc. London, 162(1), pp. 50-52, pis. 3-4. 294 MOORE: BEAKED WHALES 295 1953. Report on Cetacea stranded on the British coasts from 1938 to 1947. Brit. Mus. (Nat. Hist.), 1953, pp. 1-48. 1955. A skull of Mesoplodon gervaisi (Deslongchamps) Trinidad, West Indies. Ann. Mag. Nat. Hist., (12), 8(92), pp. 624-630. Fraser, F. C. and P. E. Purves 1960. Hearing in cetaceans. Evolution of the accessory air sacs and the struc- ture and function of the outer and middle ear in recent cetaceans. Bull. Brit. Mus. (Nat. Hist.), Zool., 7(1), pp. 1-140, 53 pis., 34 figs. Glauert, L. 1947. The genus Mesoplodon in western Australian seas. Australian Zool., 11(2), pp. 73-75, lpl. Gray, J. E. 1846. On the cetaceus animals. Pp. 13-53. In John Richardson and John Edward Gray, eds. Zoology of the H.M.S. Erebus and Terror . . . 1839 to 1843. London, 1844-1875, vol. I, Mammalia, xii + 1-53 pp., color plates 1-29 and black and white plates 1-37. 1866. Catalogue of seals and whales in the British Museum. Brit. Mus. (Nat. Hist.), vii+402 pp., 101 figs. Guiler, E. R. 1966. A stranding of Mesoplodon densirostris in Tasmania. J. Mammal., 47(2), p. 327. 1967. Strandings of Mesoplodon hectori, M. bowdoini and M. layardi in Tas- mania. Jour. Mamm., 48(4), pp. 650-652. Haast, J. VON 1877. Notes on the skeleton of Epiodon novae-zeallandiae. Trans. New Zealand Inst, for 1876, 9(LIV), pp. 430-442, 2 pis. 1880. Notes on Ziphius [Epiodon) novae-zealandiae, von Haast — Goose-beaked whale. Trans. New Zealand Inst, for 1879, 12, pp. 241-246, pi. 7. Hale, H. M. 1931. Beaked whales — Hyperoodon planifrons and Mesoplodon layardi — from South Australia. Rec. S. Australian Mus., 4(3), pp. 291-311, 27 figs. 1932. The New Zealand scamperdown whale {Mesoplodon grayi) in South Au- stralian waters. Rec. S. Australian Mus., 4(4), pp. 489-496. 1962. Occurrence of the whale Berardius arnuxi in Southern Australia. Rec. S. Australian Mus., 14(2), pp. 231-243, 2 pis., 1 fig. Harmer, S. F. 1924. On Mesoplodon and other beaked whales. Proc. Zool. Soc. London, 1924, pp. 541-587, pis. 1-4, figs. 1-10. 1927. Report on the Cetacea stranded on the British coasts from 1913 to 1926. Brit. Mus. (Nat. Hist.), 10, pp. 1-91, 42 figs. Hershkovitz, P. 1966. Catalog of living whales. Bull. U. S. Nat. Mus., 246, viii +259 pp. Kellogg, R. 1928. The history of whales — their adaptation to life in the water. Quart. Rev. Biol., 3, pp. 29-76, 174-208. Kenyon, K. W. 1961. Cuvier beaked whales stranded in the Aleutian Islands. J. Mammal., 42(1), pp. 71-76, 2 pis., 1 fig. 296 FIELDIANA: ZOOLOGY, VOLUME 53 Kernan, J. D. 1918. The skull of Ziphius cavirostris. Bull. Am. Mus. Nat. Hist., 38, pp) 349- 394, pis. 20-32. Kirino, T. 1956. On the number of teeth and its variability in Berardius bairdi, a genus of the beaked whale. Okajimas Fol. Anat. Jap., 28(1-6), pp. 429-434, 1 pi. Krefft, G. 1870. Notes on the skeleton of a rare whale, probably identical with Dioplodon sechellensis. Proc. Zool. Soc. London, 1870, p. 426. Longman, H. A. 1926. New records of Cetacea. With a list of Queensland species. Mem. Queensland Mus., 8(3), pp. 266-278, 1 pi. Lydekker, R. 1911. A rare beaked whale. Proc. Zool. Soc, London, 1911, pp. 420-422, figs. 137-139. McCann, C. 1961. The occurrence of the southern bottle-nosed whale Hyperoodon plani- frons Flower in New Zealand. Rec. Dominion Mus., New Zealand, 4(3), pp. 25-27, 3 pis. 1962a. Key to the family Ziphiidae, beaked whales. Tuatara, 10(1), pp. 13-18, 2 pis. 1962b. The taxonomic status of the beaked whale, Mesoplodon hectori (Gray) — Cetacea. Rec. Dominion Mus., 4(9), pp. 83-94, 5 pis. 1962c. The taxonomic status of the beaked whale, Mesoplodon pacificus Long- man — Cetacea. Rec. Dominion Mus., 4(10), pp. 95-100. Moore, J. C. 1953. Distribution of marine mammals to Florida waters. Am. Midi. Natur., 49(1), pp. 117-158, 15 figs. 1958. A beaked whale from the Bahama Islands and comments on the distri- bution of Mesoplodon densirostris. Am. Mus. Novitates, 1897, pp. 1-12, 9 figs. 1960. New records of the Gulf-stream beaked whale, Mesoplodon gervaisi, and some taxonomic considerations. Am. Mus. Novitates, 1993, pp. 1-35, figs. 1-9. 1963a. The goose-beaked whale, where in the world? Chgo. Nat. Hist. Mus., Bull., 34(2), pp. 2, 3, 8, 3 figs. 1963b. Recognizing certain species of beaked whales of the Pacific Ocean. Am. Mid. Natur., 70(2), pp. 396-428, 16 figs. 1966. Diagnoses and distributions of beaked whales of the genus Mesoplodon known from North American waters. 2, pp. 32-61, figs. 1-12. In Norris, K. S., ed., Whales, Dolphins, and Porpoises. Univ. Calif. Press, Berkeley, xviii-j-789 pp., illus. Moore, J. C. and R. M. Gilmore 1965. A beaked whale new to the western hemisphere. Nature, 205(4977), pp. 1239-1240. Moore, J. C. and F. G. Wood, Jr. 1957. Differences between the beaked whales, Mesoplodon mirus and Meso- plodon gervaisi. Am. Mus. Novitates, 1831, pp. 1-25, 5 figs. Moreno, F. P. 1895. Nota sobre los restos de Hyperoodontes conservados en el Museo de la Plata. Anales del Museo de la Plata, seccion Zool. Ill, pp. 1-8, 2 pis. MOORE: BEAKED WHALES 297 Mousset, G. and R. Duperier 1956. Note sur le Mesoplodon mirus. Bull. Centre d'Etudes Recherches Sci. Biarritz, 1(1), pp. 33-39, 6 figs. Nishiwaki, M. and T. Kamiya 1958. A beaked whale Mesoplodon stranded at Oiso Beach, Japan. Sci. Rept. Whales Res. Inst., Tokyo, no. 13, pp. 53-84, 17 pis. 1959. Mesoplodon stejnegeri from the coast of Japan. Sci. Rept. Whales Res. Inst., no. 14, pp. 35-48, 10 figs., 4 pis. Norris, K. S., ed., by The Committee on Marine Mammals, American Society of Mammalogists. 1961. Standardized methods for measuring and recording data on the smaller cetaceans. J. Mammal., 42(4), pp. 471-476, 1 fig. Oliver, W. R. B. 1922. A review of the Cetacea of the New Zealand seas. Proc. Zool. Soc. Lon- don, 1922, pp. 557-585, 4 pis. 1937. Tasmacetus shepherdi: a new genus and species of beaked whale from New Zealand. Proc. Zool. Soc. London (B), 1937(3), pp. 371-381, pis. 1-5. Omura, H., K. Fujino, and F. Kimura 1955. Beaked whale Berardius bairdi of Japan with notes on Ziphius cavirostris. Sci. Repts. Whales Res. Instit., 10, pp. 89-132, 10 pis. Owen, Richard 1870 to 1889. Monograph on the British fossil Cetacea from the Red Crag. London, Paleontol. Soc, pp. 1-40, pis. I-V. Paulus, Marcel 1962. Etude osteographique et osteometrique sur un Ziphius cavirostris G. Cuvier, 1823 echoue a Marseille-Estaque en 1879. Bull. Mus. d'Hist. Nat. Marseille, 22, pp. 17-48, 3 pis. Pike, G. C. 1953. Two records of Berardius bairdi from the coast of British Columbia. J. Mammal., 34(1), pp. 98-104, 1 pi. Rankin, J. J. 1956. The structure of the skull of beaked whale, Mesoplodon gervaisi Deslong- champs. J. Morphol., 99(2), pp. 329-358, 9 figs. Raven, H. C. 1937. Notes on taxonomy and osteology of two species of Mesoplodon (M. europ- aeus Gervais, M. mirus True). Am. Mus. Novitates, 905, pp. 1-30, 15 figs. 1942. On the structure of Mesoplodon densirostris, a rare beaked whale. Bull. Am. Mus. Nat. Hist., 80(2), pp. 23-50, figs. 1-26. Scheffer, Victor B. and Dale W. Rice 1963. A list of the marine mammals of the world. U. S. Fish and Wildlife Service, Spec. Sci. Rept. Fisheries No. 431, pp. 1-12. Simpson, G. G. 1945. The principles of classification and a classification of mammals. Bull. Am. Mus. Nat. Hist., 85, xvi+350 pp. Slipp, J. W. and F. Wilke 1953. The beaked whale Berardius on the Washington coast. J. Mammal., 34(1), pp. 105-113, 2 pis. 298 FIELDIANA: ZOOLOGY, VOLUME 53 Stephen, A. C. 1931. True's beaked whale (Mesoplodon minis) new to the Scottish fauna. Scottish Natur., 1931, pp. 37-39, 1 fig. (^— . 1932. Notes on some whales recently stranded on the Scottish coast. Scottish Natur., 1932, pp. 164-165, fig. 1. s Talbot, F. H. 1960. True's beaked whale from the southeast coast of South Africa. Nature, 186(4722), p. 406. Thompson, W. 1846. Notice of a bottlenosed whale, Hyperoodon butzkopf, Lacep., obtained in Belfast Bay in October 1845. Ann. Mag. Nat. Hist., 17, pp. 150-153, pi. 4, figs. 1-2. Thorpe, M. R. 1938. Notes on the osteology of a beaked whale. J. Mammal., 19(3), pp. 354- 362, 4 pis. Tietz, R. M. 1966. The southern bottle-nose whale, Hyperoodon planifrons, from Hume- wood, Port Elizabeth. Annals Cape Provincial Mus., 5, pp. 101-107. True, F. W. 1910. An account of the beaked whales of the family Ziphiidae in the collection of the U. S. National Museum. Bull. U. S. Nat. Mus., 73, v+89 pp., 42 pis. Turner, W. 1885. On the occurrence of the bottle-nosed or beaked whale (Hyperoodon ros- tratus) in the Scottish seas, with observations on its external characters. Proc. Roy. Phys. Soc. Edinburgh, IX, pp. 25-47, 4 figs. Van Beneden, P. S. and Paul Gervais 1880. Osteographie de cetaces vivant et fossiles. Paris, 2 vols, (text and atlas), pp. 1-634, pis. 1-64. Waite, E. R. 1913. A supposed occurrence of the bottle-nosed whale (Hyperoodon) in New Zealand. Rec. Canterbury Mus. (N.Z.), 2, pp. 23-26, pis. vii, viii. Publication 1063