ON THREE ODONTOCETE SKULLS
FROM HEARD ISLANDERIC R. GUILER*, HARRY R. BURTON**,
AND NICHOLAS]. GALES**ABSTRACTTwo crania and a rostrum were recovered from Heard Island by the1985 Australian National Antarctic Expedition to that island. The specimens
were assigned to three species, two of which, Globicephala melaena andMesoplodon layardi, are confirmed other than by sighting reports as occurringin Antarctic Seas. The third species, Phocaena spinipinnis, of which cranialmeasurements are given, was previously known only from coastal SouthAmerican waters and is shown to have a much wider distribution thanhitherto suspected.
INTRODUCTION

Heard Island (Lat. 53 °S, Long. 73 ° 30' E) is infrequently visited but served asa base for an Australian National Antarctic Expedition which camped on theisland from October to November, 1985. Three cetacean skulls were broughtback from the island by the party and these were the first collection, albeit
small, of whale material from the island.
THE SPECIMENS

Pilot whale, Globicephala melaena (L.)
A complete cranium with some minor damage to the ventral surface wasrecovered from an entire skeleton stranded on the northern face of the Spiton the eastern extremity of the island. The carcase was estimated to havebeen stranded for less than a year. Another skeleton, possibly of the samespecies, was stranded 500 metres distant on the same beach but the skull wasmissing. Both carcases had been exposed for an apparently similar period andmuch of the external covering remained. The cranium was full of brain tissue
when collected. The baso-condylar length was 62.7 cm.
The cranium was identified from photographs in the collection of one ofus (E. R. G.) which had previously been assigned to this species by Dr P.H. vanBree.
* Zoology Department, The University of Tasmania, Hobart, Tasmania, Australia 7001.
** Antarctic Division, Department of Science, Kingston, Tasmania, Australia 7150.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987, 117-124

118

GUILER, BURTON AND GALES

According to Watson (1981) pilot whales have been sighted by whaling
expeditions as far south as the Antarctic Convergence but they were not listed
by Parker ( 1978) or Brownell ( 197 4) as occurring in Antarctic Seas. However,Globicephala has been sighted at sea in these waters, a school of at least 6
individuals being sighted by one of us (E.R.G.) in Lat. 60° OS'S, Long. 90°
lO'E on 23 Jan. 1980 and a large group of 75 individuals was sighted in 60°
44'S, 55° 51 'W by the "Polar Star" (Hanson and Erickson, 1985). These twoauthors quote a personal communication from P. Best to the effect that over1750 of these whales were sighted south of 60°S by five I. W. C. cruises. All ofthese reports are to the south of Heard Island.
Mercer (1975) noted that the northern form of Globicephala melaena
penetrated into Arctic waters during the summer period in pursuit of squid
and it would seem likely that a similar seasonal migration into Antarctic waters
takes place.
The record from Heard Island represents the first confirmation by skeletal
evidence that pilot whales occur south of the Antarctic Convergence.
The cranium has been lodged in the Tasmanian Museum, Reg. No. A1409.
Strap-toothed Whale, Mesoplodon layardi (Gray)
The material consisted only of the rostrum of which about 1 cm was missing from the distal end (Fig. 1). The right maxilla was intact but the left was
broken on both the posterior and post-lateral borders. The internal nares
were intact but all of the posterior cranium, including the vertex, was missing.
The ventral surface of the posterior rostrum was extensively damaged with allof the ventral bones either absent or reduced by erosion. No mandibles, teeth,
jugal arch or otic bones were found.
The rostrum was dry and clearly had been ashore for many years.
The asymmetry of the nasals clearly assigned the rostrum to the Fam.
Ziphiidae and the arrangement of the antorbital notch, maxillary tubercle andthe premaxillary and maxillary foramina indicated that the specimen could beassigned to Mesoplodon layardi. The steps in this identification are intended tobe published elsewhere by the senior author.
The firm sutures indicated that the specimen was derived from an adultwhale.
The bones of the beak were strongly sutured with no space between thedorsal surfaces of the premaxillaries and the maxillaries. The mesorostralgroove was filled by osseus material which was believed to b.e a feature of themale (Besharse, 1971). However, Moore (1960) had earlier noted that thegroove filled more slowly in females than in males and he suggested that thiswas also an age related factor. To some extent this view was supported by thefindings of McCann (1965) who observed that the groove was filled with replacing bone formed by the transformation of the mesethmoid cartilage, commencing at the proximal end. He found that there was some sexual
dimorphism in that the groove in females often is irregular and not completely
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

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Falkland Is (Bruyns, 1971; Rice, 1977) and Tierra del Fuego (Goodall, 1978).
It is relatively common in New Zealand (Gaskin, 1972). The Australian records
were reviewed by Dixon ( 1980) and a breeding population occurs in or close
to Tasmanian waters (Guiler, 1984). The species has been sighted by whaling
fleets as far south as the Antarctic Convergence (Watson, 1981), but it was notlisted as living in Antarctic Seas by Brownell (1974), nor do there appear to be
any records of this whale from the Antarctic Peninsula or the associated islands.
The present record from Heard Is. is the first report of this species fromsouth of the Antarctic Convergence and also is the first time that the genus
Mesoplodon has been recorded from Antarctic Seas.
The specimen has been deposited in the Tasmanian Museum, Reg. No.
Al410.
Burmeister's porpoise, Phocaena spinipinnis Burmeister
The genus Phocaena until recently was represented in southern waters by
two species, P. spinipinnis (Burmeister) and P. dioptrica Lahille. The latterspecies has recently been moved into the new genus Australophocaena
TABLE 1. CERTAIN SKULL MEASUREMENTS OF AUSTRALOPHOCAENA DIOPTRICA,
P. SPINIPINNIS AND THE SKULL FROM HEARD ISLAND
A. dioptrica(Baker, 1977)

Cranio-basal lengthMax. heightPre-orbital width
Zygomatic width
Max. width
Parietal width
Rostral length
width at basemiddleflengthheight at middle
Width premax. at middle
Height premax. at middle
Length of fused premax.
to ant. margin of nares
to vertex of nasalsof temporal fossa
Height of temporal fossa
Length of upper 1. toothrow
upper r. toothrow
Ratio width to length of rostrum
width of skull to length
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

310
155
162
180
180
157
117
84
51
51
15
29
3.5
open
165
221
61
58
81
82
0.727

P. spinipinnis
Norris andMacfarland, 1958

273

168

152
83

open

79
0.517
0.560

Heard Is.
skull
303
163
164
169
169
156
162
82
51
38
24
315
open
159
235
42
39
71
79
0.513
0.550

122

GUILER, BURTON AND GALES(Barnes, 1985). A good comparison of these two species is given by Norrisand McFarland (1958) together with details of two northern hemispherespecies, P. sinus Norris and McFarland and P. phocaena (L.).
The specimen was relatively fresh and in our opinion the porpoise had
been stranded within the prior 12 months.
The skull was complete except for the absence of teeth and mandibles
and some minor damage in the palatine and otic regions. The jugal arches
were absent.
The skull is identified as belonging to Phocaena spinipinnis Burmeister.
This identification is based on a comparison of the specimen with photographs
in Norris and McFarland (1958) which showed good agreement in the featuresof the skull and the arrangement of the sutures (Fig. 2).
The measurements of the skull show that this was a large individual(Table 1) and this fact, combined with the complete closure of all the sutures,indicates that the animal was an adult.
Although the skull was larger than that described by Norris and McFarland,
the ratio of rostral width : rostral length (0.513) is similar to that found by
those two authors (0.517) as is the ratio of skull length : skull width (0.55
compared to 0.560). These ratios are different from those found for P. sinus(0.630 and 0.637 respectively) and for P. phocaena (0.470 and 0.537). The
rostral proportions for A. dioptrica are 0.737.
The number of alveoli in the upper jaw of the Heard Is. specimen was
14 on the left side and 13 on the right which is similar to that for P. spinipinnis
whereas A. dioptrica and P. sinus have a total of 45 and 46 alveoli respectively.
DISTRIBUTION OF BURMEISTER'S PORPOISE

Burmeister's Porpoise has hitherto been known only from the southern Atlanticand Pacific coasts of South America (Praderi, 1971), extending as far as
Uruguay (Pilleri and Gihr, 1972, 1975). The presence of the cold waters on
the western side of the continent enables the species to range as far as Peru
where one was found in a fish market at Chimbote (Clarke, 1962). Watson( 1981) believed it possible that substantial numbers of this so-called rare
porpoise were sold every year in the 100,000 kg or more of dolphin meat
which passes annually through the fish markets.
No records have come to our attention of the presence of this species
around the Antarctic Peninsula.
This record is evidence of a wider distribution of this species than its
previously known limits. The porpoise must be able to undertake oceanic trips
and it must be able to make penetrations into Antarctic waters, at least to theextent of crossing the Antarctic Convergence.
This is not the only South American "coastal" porpoise which has beenfound on Antarctic or Sub-Antarctic islands. The spectacled porpoise,
Australophocaena dioptrica (Lahille), has been discovered in comparatively
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

ODONTOCETESKULLS

123

recent years to occur in the Auckland Islands (Baker, 1977) and at Macquarie
Island (Fordyce, Mattlin and Dixon, 1984). Neither of these localities are
south of the Convergence. This species may have been seen at sea near New
Zealand (Cawthorn, 1977) as well as at the Kerguelen Islands (Frost and Best,1976).
We suggest that a similar distribution could eventually be found for
Phocaena spinipinnis.
The cranium has been lodged in the Tasmanian Museum, Reg. No. Al411.

ACKNOWLEDGEMENTSThanks are given to all members of the 1985 A. N. A. R. E. to Heard Island
whose field support made this collection possible. We also wish to thank thestaff of the Photographic Section, Antarctic Division for the photographs ofthe specimens.

REFERENCESBAKER, A. N., 1977. Spectacled porpoise, Phocaena dioptrica, new to the Subantarctic Pacific Ocean. N. Z.J.
Mar. Freshw. Res., 11: 401-6.
BARNES, L. G., 1985. Evolution, taxonomy and antitropical distributions of the porpoises (Phocaenidae,Mammalia). Mar. Mammal. Sci., 1: 149-65.
BESHARSE, J.C., 1971. Maturity and sexual dimorphism in the skull, mandible and teeth of the beaked
whale Mesoplodon densirostris.]. Mammal., 52: 297-315.
BROWNELL, R. L., 1974. Small Odontocetes of the Antarctic. American Geographical Society Antarctic Map Folio
Series. Folio 18.
BRUYNS, W.F.J.M., 1971. Field Guide to the Whales and Dolphins. Amsterdam. 258pp.
CAWTHORN, M., 1977. Whale Identification. Field Guide for New Zealand Whales. Mimeo. (quoted byFordyce et al., 1984).
CLARKE, R., 1962. Whale observations and whale marking off the coast of Chile. Norsk Hvalfangst-Tid., 51:265-87.
DIXON, J. M., 1980. A recent stranding of the Strap-toothed whale, Mesoplodon layardi (Gray) (Ziphiidae)
from Victoria and a review of Australian records for the species. Viet. Nat., 97(1): 34-41.
FORDYCE, R. E., R.H. MATTLIN and J. M. DIXON, 1984. Second record of spectacled porpoise from
Subantarctic southwest Pacific. Sci. Rep. Whales Res. Inst., 35: 159-64.
FROST, P. G. M. and P. B. BEST, 1976. Design and application of a coded format for recording observationsof cetaceans at sea. S. Afr.]. Antarct. Res., 6: 9-14.
GASKIN, D.E., 1972. Whales, Dolphins and Seals. Heinemann, Auckland. 200pp.
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.
GUILER, E. R., 1984. A young Strap-toothed whale in Tasmanian waters. Pap. Proc. R. Soc. Tasm., 118: 65-8.
HANSON, M. B. and A. W. ERICKSON, 1985. Sightings of toothed whales along the Antarctic coast and in theSouth Atlantic Ocean. Antarctic journal of the United States, 20(2): 16-19.
MERCER, M. C., 1975. Modified Leslie-Delury population models of the long-finned pilot whale (Globicephalamelaena) and an annual production of the short-finned squid (lllex cerebrosus) based on their interaction
at Newfoundland.]. Fish. Res. Bd. Can., 32(7): 1145-54.
McCANN, C., 1965. The mesorostral groove in Ziphiidae, with special reference to its closure by ossificationin Mesoplodon - Cetacea. Ree. Dom. Mus., 5: 83-8.
Sci. Rep. Whales Res. Inst.,No. 38, 1987

124

GUILER, BURTON AND GALESMOORE, J.C., 1960. New records of the Gulf Stream Whale, Mesoplodon gervaisi, and some taxonomic
considerations. Amer. Mus. Novitat., 1993: 1-34.
NORRIS, K.S. and W.N. MACFARLAND, 1958. A new Harbor Porpoise of the genus Phocaena from the Gulfof California.]. Mammal., 39: 22-39.
PARKER, D.A.A., 1978. Observations of whales on ANARE voyages between Australia and Antarctica. Aust.
Wildl. Res., 5: 25-39.
PILLER!, G. and M. GrnR, 1972. Burmeister's Porpoise, Phocaena spinipinnis Burmeister, 1865 off the Punta<lei Diablo, Uruguay. Investigations on Cetacea, 4: 171-81.
PILLER!, G. and M. GrnR, 1975. Second record of Burmeister's Porpoise, Phocaena spinipinnis, off LosCerres, Uruguay. Investigations on Cetacea, 5: 151-3.
PRADER!, R., 1971. Contribucion al conocimiento de Genero Phocaena (Cetacea: Phocaenidae). Rev. Mus.
Argent. Cienc. nat. Bernardino Rivadavia Inst. nac. Inv. Sci. nat. (Zool.), 7: 251-66.
RICE, D. W., 1977. A list of the marine mammals of the world. NOAA Tech. Rep. NMFS SSRF, 711: 1-15.
WATSON, L., 1981. Sea Guide to Whales of the World. Hutchinson, London. 302pp.

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