Art. XXIII.—Notes on the Dolphins of the New Zealand Seas.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 17, 1884, Page 207

Art. XXIII.—Notes on the Dolphins of the New Zealand Seas. By James Hector, C.M.G., M.D., F.R.S. [Read before the Wellington Philosophical Society, 26th November, 1884.] In 1872** Trans. N.Z. Inst., vol. v., art. xix. I collected all the information at my command respecting the dolphins that frequent our coasts, and distinguished the species according to the mode of classification adopted by the late Dr. Gray hi his catalogue.

In 1876, when describing the osteology of Tursio metis, I pointed out the importance of the palatal aspect as affording a ready means of distinguishing the skulls of our dolphins, and gave figures of this aspect for the five species of most frequent occurrence.** Trans. N.Z. Inst., ix., pl. xii. So far as I know, no additions have been made to our knowledge of the subject by observation in this country since then, but the general classification of the Delphinidæ has been considerably modified, so that it has become necessary to revise our lists. Unfortunately the great work of Van Beneden and Gervais, which was looked forward to as likely to afford us an authoritative settlement of many difficult questions, fails us in respect to the dolphins, owing to the death of Professor Gervais before this section of the work was written. Professor Flower has, however, taken up the subject in a masterly paper contributed to the Zoological Society,†† Proc. Zool. Soc. Lond., 1884, p. and has done much in clearing the ground for more correct observation and study of this most difficult class of animals. The key-note of this revision by Professor Flower is that he places no dependence on the number and size of teeth, or the form and proportions of the brain-case and of the beak, all of which were the chief characters relied on by Dr. Gray, and attaches most importance to the features presented by the palatal aspect of the skull, and particularly the condition of the pterygoid bones, which, he points out, in all the Delphinidæ enclose a large air-sinus. Adopting the classification thus indicated, the following is the revised nomenclature of the New Zealand Delphinidæ:— 1. Orca gladiator, Gray, p. 279 (Orca, pacifica, Gray, Proc. Zool. Soc., 1870; Hector, Trans. N.Z.Inst., vii., 260.) Two complete skeletons of the Killer are now in the Museum, one having been obtained from Tasmania and the other from the coast south of Wanganui. I consider that there is no valid ground for separating the southern from the northern species. The New Zealand species is the larger and more robust of the two specimens, and measures 21 feet in total length. The number of vertebræ is as follows:— Cervical 7 First 4 anchylosed. Dorsal 11 Lumbar 10 Sacral 15 Caudal 9 52 The size of the skull exceeds by ⅕ that of the large skull in the Otago Museum which I formerly described (Trans. N.Z. Inst., vii., 260.)

2. Pseudorca crassidens, Owen; Gray, 290 (P. meridionalis, Flower, Proc. Zool. Soc., 1864; Hector, Trans. N.Z. Inst., v., 163.) Professor Flower states that further examination of a complete series of adult skeletons has led him to abandon the specific distinction of the southern from the northern form of this animal. No further specimen of this rare animal has been obtained since my former notes were published. 3. Grampus richardsoni, Gray, 299 Hector, Trans. N.Z. Inst., v., 163 Nothing more has been ascertained as to the occurrence of this grampus in the New Zealand seas. It is probably identical with Grampus griseus of the northern seas, which Professor Flower states is remarkable for the variability of its colour. 4. Delphinapterus leucas, Pallas (Beluga, kingii, Gray, 309; Hector, Trans. N.Z. Inst., v., 163.) The inclusion of this animal in the New Zealand Fauna is still only dependent on the single specimen of an imperfect skull. A skull of the northern species, which I obtained for comparison, agrees so well that it is better to sink the specific distinction until definite information is obtained. 5. Globicephalus melas, Traill G. macrorhynchus, Gray; Hector, Trans. N.Z. Inst., v., 164 A number of skeletons of this very common animal known as the blackfish have been sent by me in exchange to other museums, and Professor Flower has satisfied himself that it cannot be separated from the Caaing whale of the Northern Seas. Professor Flower considers that the skull in the College of Surgeons Museum which forms the type G. macrorhynchus belongs to a different animal; but the description quoted by Gray of the South Sea blackfish and its habits under that specific name so evidently apply to our common blackfish that I was misled in my former determination. 7. Cephalorhynchus hectori, Van Beneden. Lagenorhynchus clanculus, Gray. Electra clancula, Hector, Trans. N.Z. Inst., v., 160 The common dolphin of the coast which I at first identified as this species has given rise to a most embarrassing confusion of nomenclature from its evidently having been confounded with another dolphin almost equally common and of the same size, Clymenia obscura. Following the nomenclature of Gervais, and guided by the character of the pterygoid bones, Professor Flower refers it to the genus Cephalorhynchus, which with Gray was a sub-genus of Tursio, and considers it barely distinguishable from Gray's Tursio heavisidii of the Cape of Good Hope, which is, however,

described as having the teeth 25/25, whereas our dolphin has teeth 32/32. Moreover, the dorsal fin in the Cape species is stated to be triangular, while in ours it is rounded as shown in my original sketch. This feature has been confirmed by Van Beneden, who has founded a new species under the name of Electra hectori (Bull. Acad. Roy. de Belgique, 1881) on a very complete specimen presented to him by Dr. Finsch, who obtained it on the north-east coast of New Zealand. The only discernible difference in the description of the two animals is that the nose and forehead were white in my specimen, and black in Dr. Finsch's, a character of small importance where all the other colouration is the same. According to Professor Flower, Electra clancula is only founded on a skull, and this skull, although agreeing in other respects, differs so materially in the form of its pterygoid—a character which Gray does not allude to—from our species that he places it almost in the same species as the Cape dolphin, distinguished by the specific name conferred by Van Beneden. The statement which I made in the first notes of this dolphin, to the effect that the “cervical vertebræ” are anchylosed, should probably have been “anterior cervical vertebræ,” and I have to thank Professor Flower for pointing out the error; but, unfortunately, until new specimens have been obtained and prepared, the complete osteology cannot be compared, as both the complete skeletons which I recorded as being in the Museum have been given away, one to the “Challenger” Expedition, and the other to the British Museum, under the impression that there was a third complete specimen in store. This latter has been recently cleaned, and proves to be altogether a different species, but one with which, as already stated, the present dolphin is often confounded. 8. Delphinus delphis, Zimm. D. forsteri, Gray; Hector, Trans. N.Z. Inst., v., 158. D. novæ-zealandiæ, Q. and G.; Hutton, Trans. N.Z. Inst., ix., 349 Comparison of these types with a large number of specimens from these seas has enabled Professor Flower definitely to determine that the above species are in every character identical, thus adding another to the list of Cetaceans that have a world-wide geographical range. In the Museum there is a fairly complete skeleton of this species, and a number of skulls and lower jaws. 9. Tursiops tursio, Buonaterre. Tursio metis, Gray; Hector, Trans. N.Z. Inst., v., 162 These species are now considered to be closely allied, if not identical. A comparison of a complete skeleton in the Museum with the descriptions and anatomical drawings of the northern species does not afford any ground for keeping them as distinct species.

10. Clymenia obscura, Gray. Hector, Trans. N.Z. Inst., v., p. 160 This species was first described as a Tursio, and placed in the sub-genus Cephalorhynchus. By Gervais it is figured as an Electra, (Lagenorhynchus breviceps), and altogether its synonomy is in a very unsatisfactory state. Yet it is not uncommon, frequenting the coast in large “schools” in a similar manner to the other small dolphin (Cephalorhynchus hectori), from which it is easily distinguished when swimming, by its high-pointed dorsal fin-lobe. Also it is uniform black above, white beneath, with a black streak over the eye. There is a stuffed skin, a complete skeleton, and some skulls of this species in the Museum. The number of vertebræ is 71, viz., 7 cervical, of which the first two are united, 13 dorsal, 19 lumbar, 21 sacral, and 11 caudal. 11. Clymenia euphrosyne, Gray. C. novæ-zealandiæ, Hector, Trans. N.Z. Inst., v., 159 The skull which I described under the second of these names, I now decide, from having had access to better drawings, to refer to Gray's species as above. In the Museum we have also skulls of Clymenia dubia, Cuvier, and C. attenuata, Gray, but there is some doubt if they were captured within the New Zealand area.