SECOND RECORD OF SPECTACLED PORPOISE
FROM SUBANTARCTIC SOUTHWEST PACIFIC
R. EWAN FORDYCE
Department of Geology, University of Otago, P, 0. Box 56,Dunedin, New Zealand

ROBERT H. MATTLIN
Fisheries Research Division, Ministry of Agriculture and Fisheries,
P. 0. Box 297, Wellington, New Zealand

JOAN M. DIXON
National Museum of Victoria, 285-321 Russell Street,Melbourne, Victoria 3000, Australia

ABSTRACTAn incomplete skull of unknown sex of a sub-adult spectacled porpoise(Phocoena dioptrica Lahille, 1912) was collected at Macquarie Island (54°30'S,159°00'E) in July 1957. Cranial measurements are given, and the specimen
is compared with other phocoenids. This is the second specimen of P. dioptrica
reported from the subantarctic southwest Pacific, and this record adds support to the suggestion that the species may have a circumpolar distribution insubantarctic latitudes.
INTRODUCTION

The spectacled porpoise (Phocoena dioptrica Lahille, 1912) is a little-studied austral
species of the Family Phocoenidae. It is known primarily on the basis of specimens from the southwest Atlantic Ocean (Brownell, 1975), particularly Tierra delFuego (Goodall, 1978; Goodall and Cameron, 1979). Hitherto, the only specimen collected outside South American waters was National Museum of NewZealand (NMNZ) Mal670, from Auckland Islands, southwest Pacific (Baker,1977). The species apparently has been sighted alive near New Zealand (Cawthorn, 1977), and possibly Kerguelen (Frost and Best, 1976). Here we report details of a second specimen of P. dioptrica from the subantarctic southwest Pacific.
DESCRIPTION OF SPECIMEN

The specimen is an incomplete skull (Plates I and II, Figs 1-4) of unknown sex,
collection number Cl0323, in the National Museum of Victoria (NMV), Melbourne,Victoria, Australia. It was collected at Aerial Cove, Cataline Point, Macquarie
Island (latitude 54°30'S, longitude 159°00'E) by S. Csordas (Australian National
Antarctic Research Expedition) on 24 July 1957. The skull is damaged, and lacks
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FORDYCE, MATTLIN AND DIXONTABLE 1.

CRANIAL MEASUREMENTS OF PHOCOENA DIOPTRICA,NMV Cl0323, TO NEAREST MILLIMETRE

Measurement

Millimetres

Condylobasal length
Length of rostrum
Width of rostrum at baseWidth of rostrum at mid-length
Width of premaxillae at mid-length
Width of rostrum at 60 mm anterior to rostrum baseWidth of rostrum at three-quarters length, measured from posterior end
Distance from tip of rostrum to external nares
Distance from tip of rostrum to broken anterior border of right internal naris
Preorbital width at level of most ventrally-produced portion of frontal
Supraorbital width, level with anterior border of right external naris
Greatest postorbital widthGreatest width of external nares (immediately posterior to broken tips ofpremaxillae)
Greatest width of premaxillae (level with anterior edge of right external naris)
Greatest parietal width (at parietal-squamosal-exoccipital suture)
Vertical external height of braincase from mid-line of basisphenoid to summitof supraoccipitalInternal length of braincase from hindmost limit of condyles to foremost limitof cranial cavity along mid-line
Greatest length of left temporal fossa
Minor diameter of left temporal fossa
Projection of premaxillae beyond maxillae at tip of rostrum
Distance from foremost end of junction between nasals to estimated hindmost
point of margin of supraoccipital crest
Length of right orbit, from most ventrally produced preorbital portion of frontal
to broken anterior edge of postorbital process
Length of antorbital process of right lacrimal
Greatest width of internal nares estimated (width of right internal naris, 28)
Length of upper right alveolar groove
Deviation of skull from symmetry in dorsal view

283
111
81

54
28

52
43
153

154
127
136

159
34

46
138

107

107

>59
30
341
45
32

56
89
ea. 4 degrees

teeth, posterior ends of the premaxillae, part of the left supraorbital process of thefrontal, the apices of both postorbital processes, lateral portions of the supraoccipital,
both squamosals, all but a fragment ofleft pterygoid, the hamulus and outer lamina
ofright pterygoid, and the left and partial right paroccipital processes. The vertex
and the apices of the rostrum and right supraorbital process are abraded. The
specimen exhibits no noteworthy differences from previously described individualsof P. dioptrica.
The absolute age of the specimen cannot be determined, as teeth, which might
exhibit incremental growth lines, are absent. Other cranial features suggest thatthe animal is sub-adult. Traces of the frontoparietal suture remain, and the basisphenoid-presphenoid suture was not fused, which suggest immaturity, but the fusion of interparietal and parietal indicates that the specimen is at least older thanthe equivalent of age-class III of Stenella attenuata as defined by Perrin (1975).
Measurements of NMV 010323 (after Perrin, 1975: Table 2) to the nearest
1 mm are given in Table 1.
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SPECTACLED PORPOISE FROM SOUTHWEST PACIFIC

161

DISCUSSION

Extant species of phocoenid are generally differentiated on the basis of external
morphology, and the only comparative description of the skulls of species of Phocoenathat we are aware of is that of Norris and McFarland (1958). Only two phocoenid
skulls (P. phocoena, NMV C24749; P. dioptrica, NMNZ Mal670) were available tous for comparison with the Macquarie Island specimen. Thus, we base our identification of NMV C10323 primarily on descriptions and/or illustrations of phocoenid
skulls given by Norris and McFarland (1958), and other authors, as follows:
Phocoena phocoena, Hamilton (1941), Norris and McFarland (1958), Van Bree et al.
(1977); P. dioptrica, Marelli (1922), Hamilton (1941), Praderi (1971), Brownell(1975), Baker (1977), Goodall (1978), Goodall and Cameron (1979); P. sinus,Norris and McFarland (1958); P. spinipinnis, Allen (1925), Praderi (1971 ), Goodall(1978); Phocoenoides dalli, True (1885), Andrews (1911), Miller (1930); and Neophocaena phocaenoides, Allen (1923), Shaw (1938), Pilleri and Gihr (1975).
On the basis of information provided in the above literature, it appears that
adult specimens of P. dioptrica differ from those of P. phocoena, P. sinus, and P.
spinipinnis in that the dorsal surfaces of the rostrum and supraoccipital are in thesame plane, the dorsal surface of the rostrum is more flattened, the premaxillae
are elevated less above the maxillae, the dorsal and ventral surfaces of the rostrum
are more nearly parallel, the apex of the rostrum is attenuated more abruptly(dorsal and lateral views), the face slopes more steeply from the vertex to the external nares (note vertex wear in Cl0323), and particularly from the vertex to thenasal tubercules, the nasals are placed more ventrally, the vertex is longer, thepostorbital portion of the cranium and temporal fossa are shorter and deeper, thepostorbital process of the frontal is more robust and has an elongate base, the zygomatic processes are exposed less in dorsal view, and the teeth are smaller, andmore loosely inserted in less prominent alveolar grooves. P. dioptrica differs also
from P. phocoena in its longer, broader skull, and convex maxillary portion of thepalate, and from P. sinus in the larger skull, posterior margin of palate with broad
W shape indentation, convex maxillary portion of the palate, and relatively less exposure of frontal on the dorsolateral portion of braincase.
Phocoena dioptrica appears to differ from Neophocaena phocaenoides in all cranialfeatures listed above except possibly the structure of the postorbital and zygomaticprocess. Also, the skull of P. dioptrica is relatively larger, the rostrum is relatively
longer, and the rostrum is bent less relative to the basicranial axis. Cranial clifferences between Phocoena dioptrica and Phocoenoides da!li are not clear from a perusalof literature, and these species appear to be similar in that, for example, the dorsal
surfaces of the rostrum and flat-topped supraoccipital are in the same plane, thedorsal surface of the rostrum is relatively flat, the face slopes steeply from the vertex to the external nares (noted by Brownell, 1975; although in the specimen of
Phocoenoides dalli figured by Miller 1930, this appears more shallow), the nasals areplaced relatively ventrally, the postorbital process is robust with a relatively long
base, the zygomatic process is poorly exposed to dorsal view, and the teeth areSci. Rep. Whales Res. Inst.,
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FORDYCE, MATTLIN AND DIXON

relatively small, and inserted in a poorly developed alveolar groove. The main
cranial differences between these species (discerned from published figures) appear
to be that the postorbital part of the cranium and the temporal fossae are relatively
shorter and deeper in P. dioptrica. The postcranial skeletons of Phocoena dioptrica
and Phocoenoides dalli are, however, very different (compare Brownell, 1975: fig. Iand Goodall and Cameron, 1979: fig. 5, with Miller, 1930: plate I). Phocoena
dioptrica is similar to other species of Phocoena while Phocoenoides dalli possesses verytall, anteroposteriorly narrow neural spines with reduced zygapophyses and anteroposteriorly narrow centra.
We identify NMV Cl0323 as Phocoena dioptrica because it exhibits features
which can be used to separate positively-identified specimens of P. dioptrica fromother species of phocoenid. However, limited information on the comparative
cranial osteology of phocoenids, as well as our limited access to specimens, makes
the above comparisons provisional and the former indicates the need for a generalreview of phocoenid osteology.
The Macquarie Island record, which is only the second positive occurrence
outside southern South American waters, certainly indicates that P. dioptrica has awider distribution than was known only a few years ago (e.g. Brownell, 1975).
This record, and sightings apparently of P. dioptrica near New Zealand (Cawthorn,1977) and Kerguelen (Frost and Best, 1976), support Barker's (1977) suggestionthat the species may have a circumpolar distribution in subantarctic latitudes. Undoubtedly, much new information on the species will result from the recent workof Goodall (1978; Goodall and Cameron, 1979) in Tierra del Fuego. Whereas
Brownell (1975) observed that only ten occurrences then were known of P. dioptrica, Goodall (1978) listed 112 specimens, and mentioned another 29, from Tierradel Fuego alone. These beach collections suggest that the spectacled porpoise is
the most common small cetacean in inshore waters around Tierra del Fuego, but
the absence of sightings of live animals even in areas of high stranding densities
attests to the cryptic behaviour of the species. It is likely that strandings, rather
than sightings of live animals, will constitute further records of the species from thesubantarctic southwest Pacific and, in view of the northward distribution of theporpoise into temperate South American waters (Brownell, 1975), strandings might
be expected in New Zealand.
ACKNOWLEDGEMENTS

We thank Alan Baker and Martin Cawthorn for discussion, and James G. Meadfor reading the manuscript. R. E. Fordyce's contribution was produced during
the tenure of a postdoctoral fellowship in the Department of Earth Sciences, Monash
University, Clayton, Victoria, with the assistance of facilities of the National Museum of Victoria, Melbourne, Victoria, Australia.

Sci. Rep. Whales Res. Inst.,
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SPECTACLED PORPOISE FROM SOUTHWEST PACIFIC163

REFERENCES
ALLEN, G. M., 1923. The black finless porpoise Neomeris. Bull. Jov!us. Comp. Zool., 65: 233-256.
ALLEN, G. M., 1925. Burmeister's porpoise (Phocaena spinipinnis). Bull. Mus. Comp. Zool., 67: 251-261.
ANDREWS, R. C., 1911. A new porpoise from Japan. Bull. Amer. Mus. Nat. Hist., 30: 31-51.
BAKER, A. N., 1977. Spectacled porpoise, Phocoena dioptrica, new to the Subantarctic Pacific Ocean. N.z.J.
Mar. Freshw. Res., I I: 401-406.
BROWNELL, R. L., 1975. Phocoena dioptrica. Mamm. species, 66: 1-3.
CAWTHORN, M., 1977. Whale identification (guide for New Zealand whales). Mimeo (not seen; cited by Goodall, 1978).
FROST, P.G.M., and P. B. BEST 1976. Design and application of a coded format for recording observationsof cetaceans at sea. S. Afr. J. Antarct. Res., 6: 9-14.
GooDALL, R.N.P., 1978. Report on the small cetaceans stranded on the coasts of Tierra de! Fuego. Sci.
Rep. Whales Res. Inst., 30: 197-230.
GooDALL, R.N.P., and I. S. CAMERON, 1979. Phocoena dioptrica, una nueva especie para aguas Chilenas.
Rev. Mus. Arg. Cienc. Nat., Buenos Aires, :(ool., 12: 143-152.
HAMILTON, J.E., 1941. A rare porpoise of the South Atlantic, Phocaena dioptrica (Lahille, 1912). Discovery
Rep., 21: 227-234.
LAHILLE F., 1912. Nota preliminar sobre una nueva especie de Marsopa de! Rio de La Plata. An. Mus.
Hist. Nat., Buenos Aires, 23: 269-278.
MARELLI, C. A., 1922. Phocaena stornii sp. n., una especie de marsopa de! mar austral Argentino. An. Soc.
Cient. Argent., 94: 229-240.
MILLER, G. S., 1930. A note on the skeletons of two Alaskan porpoises. Smiths. Misc. Coll., 82 (13): 1-2.
NoRRis, K. S., and W. N. McFARLAND, 1958. A new harbor porpoise of the genus Phocoena from the Gulfof California. J. Mamm., 39: 22-39.
PERRIN, W. F., 1975. Variation of spotted and spinner porpoise (Genus Stenella) in the Eastern TropicalPacific and Hawaii. Bull. Scripps Inst. Oceanogr., 21: 1-206.
PrLLERI, G., and M. GrnR, 1975. On the taxonomy and ecology of the finless black porpoise, Neophocaena(Cetacea, De!phinidae). Mammalia, 39: 657-673.
PRADERI, R., 1971. Contribucion al conocimiento de! genero "Phocoena (Cetacea, Phocoenidae) ". Rev.
Mus. Arg. Cienc. Nat., Buenos Aires, Zool., 7: 251-266.
SHAW, T. H., 1938. The skull of Chinese finless porpoise. Bull. Fan. Inst. Biol. Peking, Zool., 8: 373-385.
TRUE, F. W., 1885. On a new species of porpoise, Phocaena dalli, from Alaska. Proc. U.S. Nat. Mus., 8:95-98.
VAN BREE, P.J.H., D. E. SERGEANT, and W. HOEK, 1977. A harbour porpoise Phocoena phocoena (Linnaeus,1758), from the Mackenzie River delta, Northwest Territories, Canada (Notes on Cetacea, Delphinoides
VIII). Beaufortia, 26: 99-105.

Sci. Rep. Whales Res. Inst.,
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164

FORDYCE, MATTLIN AND DIXONEXPLANATION OF PLATESPLATES I AND II
Skull of Phocoena dioptrica, NMV C10323.
Fig. 1. Dorsal view.
Fig. 2. Left lateral view.
Fig. 3. Anterior view.
Fig. 4. Ventral view.

Skull length 283 mm.

Sci. Rep. Whales Res. Inst.,

No. 35, 1984

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