Biology of the Antarctic Seas IX

165 Pages·1978·6.3 MB·English

Osteology of the Ross Seal Ommatophoca Rossi
Gray,1844
Jean Pierard and Andre Bisaillon
Paper 1 in
Biology of the Antarctic Seas IX
Antarctic Research Series Volume 31
Louis S. Kornicker, Editor
American Geophysical Union
OSTEOLOGY OF THE ROSS SEAL OMMA TOPHOCA
ROSSI GRAY, 1844
JEAN PI£RARD AND ANDRE BISAILLON
BIOLOGY OF THE ANTARCTIC SEAS IX
Antarctic Research Series Volume 31
Edited by Louis S. KORNICKER
Copyright • 1978 by the American Geophysical Union
1909 K Street, N.W.
Washington, D.C. 20006
Library of Congress Cataloging in Publication Data
Pierard, Jean, 1934-
Osteology of the Ross seal, Ommatophoca rossi Gray,
1844.
(Biology of the Antarctic seas; 9, paper 1)
(Antarctic research series; v. 31, paper 1)
Bibliography: p.
1. Ross seal—Anatomy. 2. Bones. 3. Mammals—
Anatomy. I. Bisaillon, Andre, 1943- joint author.
II. Title. III. Series. IV. Series: American
Geophysical Union. Antarctic research series; v. 31,
paper 1.
QH95.58.B56 vol. 9, paper 1 [QL737.P64] 574.92<4s
ISBN 0.87590-150-6 [599'.748] 78-12439
Published by the
AMERICAN GEOPHYSICAL UNION
With the aid of grant DPP77-21859 from the
National Science Foundation
March 5,1979
Printed by
THE WILLIAM BYRD PRESS, INC.
Richmond, Virginia
'.L
^<*- • -x:;\\(.^
From
Taisoo Park
' -1 • (
. Paper 2 in
Biology of the Antarctic Seas IX
Antarctic Research Series Volume 31
Louis S. Kornicker, Editor
American Geophysical Union
\ •
CALANOID COPEPODS OF THE GENUS
SCOLECITHRICELLA FROM ANTARCTIC
AND SUBANTARCTIC WATERS
TAISOO PARK
/
BIOLOGY OF THE ANTARCTIC SEAS IX
Antarctic Research Series Volume 31
Edited by Louis S. KORNICKER
Copyright © 1980 by the American Geophysical Union
2000 Florida Avenue, N. W.
Washington, D. C. 20009
Library of Congress Cataloging in Publication Data
Park, Taisoo i
Calanoid copepods of the genus Scolecithricella
from Antarctic and subantarctic waters.
(Biology of the Antarctic seas; 9, paper 2)
(Antarctic research series; v. 31)
Bibliography: p.
1. Scolecithricejla—Classification.
2. Crustacea—Classification. 3. Crustacea-
Antarctic regions—Classification. 4. Eltanin
(Ship). I. Title. II. Series. III. Series:
American Geophysical Union. Antarctic research
series; v. 31.
QH95.58.B56 vol. 9, paper 2 [QL444.C72]
ISBN 0-87590-151-4 574.92'4s [595'34] 78-31901
Published by the
AMERICAN GEOPHYSICAL UNION
With the aid of grant DPP77-21859 from the
National Science Foundation
April 11, 1980/
Printed by
THE WILLIAM BYRD PRESS, INC.
Richmond, Virginia
Osteology and Relationships of the Fishes
of the Antarctic Family Harpagiferidae
(Pisces, Notothenioidei)
Richard R. Eakin
Two New Species of Pogonophryne
(Pisces, Harpagiferidae) From
the Ross Sea, Antarctica
Richard R. Eakin
Reports on Fishes From the University of
Maine Antarctic Biological Research Program
1. Genus Pogonophryne (Pisces, Harpagiferidae)
From the South Orkney Islands
Richard R. Eakin /
Papers 3, 4, and 5 in
Biology of the Antarctic Seas IX
Antarctic Research Series Volume 31
Louis S. Kornicker, Editor
Ameriean Geophysical Union
Paper 3
Osteology and Relationships of the Fishes
of the Antarctic Family Harpagiferidae
(Pisces, Notothenioidei)
RICHARD R. EAKIN
Page 81
/x
Paper 4
Two New Species of Pogonophryne
(Pisces, Harpagiferidae) From
the Ross Sea, Antarctica
RICHARD R. EAKIN
Page 149
Paper 5
Reports on Fishes From the University of
Maine Antarctic Biological Research Program
1. Genus Pogonophryne (Pisces, Harpagiferidae)
From the South Orkney Islands
RICHARD R. EAKIN
Page 155
BIOLOGY OF THE ANTARCTIC SEAS IX
Antarctic Research Series Volume 31
Louis S. KORNICKER, EDITOR I
Published under the aegis of the
Board of Associate Editors, Antarctic Research Series
Charles R. Bentley, Chairman
Robert H. Eather, David H. Elliot, Dennis E. Hayes
Louis S. Kornicker, Heinz H. Lettau, and Bruce C. Parker
Copyright €> 1981 by v
American Geophysical Union
2000 Florida Avenue, N. W. )
Washington, D. C. 20009
Library of Congress Cataloging in Publication Data
Eakin, Richard R., 1946-
Osteology and relationships of the fishes of the Antarc­
tic family Harpagiferidae (Pisces, Notothenioidei) ; Two
new species of Pogonophryne (Pisces, Harpagiferidae)
from the Ross Sea, Antarctica; Reports on fishes from
the University of Maine Antarctic Biological Research
Program.
(Biology of the Antarctic seas ; 9, papers 3-5) (Antarc­
tic research series ; v. 31)
1. Pogonophryne—Classification. 2. Harpagiferidae^
Classification. 3. Fishes—Classification. 4. Fishes^Ant-
arctic regions—Classification. I. Series: Antarctic re­
search series ; v. 31. II. Title.
QH95.58.B56 vol. 9, papers 3-5 [QL638.H28] 64-60030
ISBN 0-87590-153-0 574.92'9s [597'.58] AACR2
Published by
AMERICAN GEOPHYSICAL UNION
/With the aid of grant DPP-7721859 from the
National Science Foundation /
November 9, 1981 '
Printed in the United States of America
Antarctic Research Series Biology of the Antarctic Seas IX Vol. 31
OSTEOLOGY OF THE ROSS SEAL OMMATOPHOCA
ROSSI GRAY, 1844
JEAN P I E R A R D AND ANDRE B l S A I L L O N
Departement d Anatomie et Physiologie Animates, Faculte de Medecine Veterinaire
Universite de Montreal, Saint-Hyacinthe, Quebec, Canada
The osteology of the Ross seal (Ommatophoca rossi) is described. The bones of this species closely
resemble those of Leptonychotes, the only other Monachinae for which a general osteology is available.
The hand and foot of Ommatophoca are relatively longer than those of other phocids, and several charac­
teristics of this seal are adaptative modifications for swimming and for swallowing large prey. Possible
sexual discriminating characteristics are discussed.
Studies of the osteology of pinnipeds are few and has been recognized for more than 130 years, very
generally old. Duvernoy [1822] described very brief­ little has been known of its habits and morphology
ly the osteology of the common seal (Phoca until recently. The main reasons for this are that the
vitulina). Some 50 years later, Lucae [1872] made a animal is nowhere very abundant in the remote ant­
more nearly complete and, especially, more func­ arctic pack ice and is usually found singly or in very
tional description of the bones of the same species. small numbers. The most detailed references to the
Two years later, Murie [1874] considered the appearance, anatomy, and habits of this species can
skeleton of the Steller's sea lion (Eumetopias be found in the works of Scheffer [1958], King
jubatus) in the thorough anatomical study he made [1964a, 1969], and Nishiwaki [1972]. The latter
of that species. Thomson [1909] published the first author listed the anatomical characteristics of the
osteology of antarctic seals, comparing several genus Ommatophoca, which includes only one
peculiarities of the Ross seal (Ommatophoca rossi), species, as follows: (1) postcanines small and
the Weddell seal (Leptonychotes weddelli) and the degenerate, occasionally absent in old animals; (2)
leopard seal (Hydrurga leptonyx). Howell [1929] orbits large, zygomatic arches drop well below level
published his well-known comparative study of both of palate; (3) upper incisors nearly equal in size,
phocids and otariids, based on the ringed seal (Pusa outer cusps slightly larger than inner; (4) interor-
hispida) and the California sea lion (Zalophus bital width greater than 18% of skull length; (5) no
califomianus). Mori [1958] essentially repeated sagittal crest. The average adult male weighs about
that part of Howell's study describing Zalophus. 180 kg and is 2.2-2.3 m long; females are slightly
King [1969] elaborated on some interesting larger. The seal is rather massive in appearance,
peculiarities of the osteology of the Ross seal and with a short neck; the head appears wide and short
also, on some specific points, referred to other ant­ with protruding eyes. The fur is brown, being darker
arctic or arctic species. A general osteology of the on the hindlimbs and the dorsal parts of the head. The
Weddell seal (Leptonychotes weddelli) was pub­ Ross seal feeds mainly on Cephalopoda, although its
lished recently [Pierard, 1971]. diet also includes fish and krill. The total population
The Ross seal (Ommatophoca rossi Gray, 1844) of this species has been estimated between 30,000
was named after Sir James Clark Ross, commander and 60,000 individuals [Nishiwaki, 1972], but an esti­
of the British antarctic expedition during the years mate of 20,000 was made by King [1964a]. A more
1839-1843. Ommatophoca derives from the Greek recent estimate by Hofman et al. [1973] establishes
word ofx ix a (eye) and refers to the large eyes and the total population of this species between 100,000
orbits of the animal. Despite the fact that the species and 150,000 individuals.
1
Copyright American Geophysical Union
Antarctic Research Series Biology of the Antarctic Seas IX Vol. 31
2 BIOLOGY OF THE ANTARCTIC SEAS IX
TABLE 1. Measurements of Specimen MCZ 52305 (Male) Drawings are of specimen MCZ 51852. The sequence
of the descriptions, nomenclature, topographical and
Measurement
directional terms used in this study are those of the
Standard length,* cm 210 Nomina Anatomica Veterinaria [World Association
Curvilinear length,* cm 214
of Veterinary Anatomists, 1973].
Anterior length of front flipper,* cm 36
Anterior length of hind flipper,* cm 47 References made to Pusa or Zalophus are from
Thickness of blubber (maximum) ,* cm 4 Howell [1929], and those to Leptonychotes from
Axillary girth,* cm 153
Pierard [1971].
Weight,* kg 238
Tail length, cm 16
Snout-axilla length, cm 80
AXIAL SKELETON
Snout-distal end of fore flipper, cm 108
Snout-umbilicus length, cm 133
Columna vertebralis. The vertebral formula of
Snout-penile aperture length, cm 144
Snout-distal end of hind flipper, cm 238 Ommatophoca rossi is C T L S Cy . Measure­
7 15 5 3 n
Posterior length of front flipper, cm 16 ments of the vertebral segments of both specimens
Greatest girth, cm 148 are reported in Table 2.
Anal girth, cm 54
Vertebrae cervicales (Figures 1 and 2): The atlas
*Committee on Marine Mammals, American Society of Mam- is characterized by the deep concavity of its fovea
malogists [1967]. articularis cranialis, the blunt and strong appearance
of its tuberculum dorsale, and the fact that the ala
The purpose of the present study is to provide a
atlantis makes an angle of approximately 90° with
detailed descriptive and functional account of the
the basicranium and that the ala atlantis bears a
osteology of the Ross seal.
strong caudal protuberance. A transverse ridge dor­
sal to the foramen transversarium is present in the
MATERIAL AND METHODS
female. The processi transversi of the axis are very
Skeletons of two specimens of Ommatophoca rossi short, each bearing a wide foramen transversarium
from the collections of the Museum of Comparative dorsally closed only by a very weak bony bridge. Be­
Zoology at Harvard University were used in this tween the processus transversus and the
study. The first, MCZ 51852, is of a female from the zygapophysis caudalis, the lateral aspect of the
western part of Ross Sea, off Victoria Land, col­ pediculus arcus vertebrae is deeply notched. The
lected in the winter of 1965-1966. No other data were processus spinosus of the axis is craniocaudally short,
available for this specimen. The second, MCZ 52305, although its general conformation is massive,
is of a male captured at Hallett Station on January especially in the female. A relatively strong tuber­
31,1967. Measurements of this specimen are given in culum ventrale separates two concave ventral sur­
Table 1. Upon its capture the animal was injected faces which extend to the distal extremities of the
with preserving fluid (1 part formaldehyde, 2 parts processi transversi. On the other cervical vertebrae
isopropyl alchohol, 0.5 part glycerin) through the the cranial and caudal articular surfaces are well
carotid artery. It was then kept refrigerated until its delimited. The tuberculum ventrale is strong on C ,
3
dissection was undertaken in July 1968. Bones were C , and C ; it is much weaker on C ; on C it is dorso-
4 5 6 7
then cleaned and prepared by boiling and scraping. ventrally high but transversally thin. The notch
TABLE 2. Proportions of the Vertebral Segments of Some Pinnipeds
Vertebrae Vertebrae Vertebrae Os Vertebrae
Genus Cervicales Thoracicae Lum bales Sacrum Coccygeales Reference
Ommatophoca
52305 (male) (256) 24.5 (740) 70.5 (310) 29.5 (124) 12.0 (410) 39.0
51852 (female) (175) 21.0 (585) 70.0 (248) 30.0 (106) 12.5 (300) 36.0
Leptonychotes 23.0 68.0 32.0 12.5 32.0 Pierard [1971]*
Phoca 35.0 69.0 31.0 Slijper [1946]
Zalophus 38.0 72.0 28.0 Slijper [1946]
Each segment is expressed as a percentage of the thoracolumbar length. Measurements in parentheses are in millimeters.
*Calculated from the data of this work.
Copyright American Geophysical Union
Antarctic Research Series Biology of the Antarctic Seas IX Vol. 31
PIERARD AND BISAILLON: OSTEOLOGY OF THE ROSS SEAL OMMATOPHOCA ROSSI GRAY, 1844 3
tuberculum dorsale
processus spinosus
foramen intervertebrale
zygapophysis caudalis
incisura alaris
pediculus arcus vertebrae
ala atlantis
foramen transversarium
foramen transversarium
" processus transversus
20mm
Fig. 1. Atlas and axis, left lateral aspect.
mentioned about the pediculus of the axis is also (female) or T (male). The fovea costalis transver­
9
present on C , C , C , and C . Between C and C the salis is well delimited from T to T (female) or T
3 4 5 6 3 7 1 13 10
laminae arcus vertebrae bear two strong tubercles, (male); from T (female) or T (male) it is fused
14 n
one on each lamina, which gradually get closer on the with the fovea costalis cranialis.
processus spinosus of subsequent vertebrae. The Vertebrae lumbales (Figure U).' Each vertebra is
processi spinosi of C and C are the shortest dorso- strongly keeled; the processi spinosi gradually
4 5
ventrally; the processus spinosus of C is higher than shorten craniocaudally from L to L . The processi
3 x 5
that of C ; there is an even increase in height from transversi of these five vertebrae are almost of the
4
the processi spinosi of C -C . The processus same length, transversally. However, from L to L
5 7 1 4
transversus is bicuspid from C to C , the latter one they become wider craniocaudally, whereas those of
3 6
being definitely larger than the others; the processus L are narrower. The strongest vertebra of the seg­
5
transversus of C is smaller and ends in one tubercle. ment is L ; it is more massive, with a more obvious
7 4
Vertebrae thoracicae (Figure 3): The corpus ver­tuberculum ventrale and heavier processi transversi.
tebrae and processi spinosi gradually elongate cra- Os sacrum (Figure 5): The general orientation of
niocaudally, on subsequent vertebrae. Strong, the bone in situ is caudodorsal. Fusion of the three
although gradually decreasing, tuberculum ventrale sacral elements is complete in the male, whereas in
is recognizable from T to T . The ventral aspect of the female, fusion lines are clearly visible ventrally
x 5
the corpus vertebrae of T , T , and T caudally as well as dorsolateral^. S is practically the only
13 14 15 x
bears two relatively strong tubercles. T is the ver­ vertebra involved in the formation of the facies
10
tebra intermedia; caudally to that vertebra the dis­ auricularis; only a very small part of the latter is
tance between the zygapophyses narrows somewhat. encompassed on S . Zygapophyses craniales and
2
The articular surfaces of the zygapophyses are well caudales are relatively well marked.
delimited. No anticlinal vertebra is recognizable. Vertebrae caudales: These vertebrae gradually
Processi mamillares are recognizable from T to T decrease and simplify going caudally. Cy bears the
13 15 2
in the female and from T to T in the male. There last complete neural arch; Cy is laterally com­
n 15 3
are processi accessorii from T to T . A fovea cos­ pressed and has two neural apophyses, weak processi
10 12
talis cranialis is present on rT and from T (female) transversi, and two relatively strong processi
1 n
or T (male) to T ; a fovea costalis cranialis and a hemales. All the other vertebrae are compressed
10 15
fovea costalis caudalis are present from T to T laterally.
2 10
Copyright American Geophysical Union
Antarctic Research Series Biology of the Antarctic Seas IX Vol. 31
4 BIOLOGY OF THE ANTARCTIC SEAS IX
lamina arcus vertebrae
foramen
transversarium
processus
transversus
20 mm
tuberculum ventrale
Fig. 2. Fifth cervical vertebra: (top) left lateral aspect and (bottom) cranial aspect.
Costae: There are 15 pairs of craniocaudally flat­ Sternum: The sternum consists of eight ster-
tened ribs. Their attachment is both capitular and nebrae; measurements for both specimens are given
tubercular except for the last two pairs, where it is in Table 3. The first two sternebrae are more or less
only capitular. In the male the first 10 ribs articulate rounded; the remaining bones are dorsoventrally
with the sternum. The length of the osseous ribs flattened, especially the caudal end of the eighth one.
gradually increases from the first to the ninth and The osseous sternum of the male is 37% of the thora­
tenth; the eleventh is shorter, and the subsequent columbar length and 53.5% of the total length of the
ribs gradually decrease in length as they also become sternum.
thinner. The curvature of the osseous ribs is never Skull Measurements of both specimens are
pronounced but is more obvious from the first to the given in Table 4. The skull is described in dorsal,
ninth rib. From the sixth to the eleventh rib there are lateral, ventral, and rostral aspects; vacuities and
two strong caudal ridges on the proximal part of each foramina of its ventrolateral aspect as well as mandi­
rib; one is medial, the other lateral. The last four ribs ble and dentition are described separately. As no
have only a caudolateral ridge which is of gradually apparatus hyoideus was available for description,
increasing size from the twelfth to the fifteenth. readers are referred to King [1969] for the descrip­
From the fourth to the fifteenth there is a strong cra­ tion of these bones.
nial ridge on the proximal half of the bone. Dorsal aspect (Figure 6): Striking features of
Copyright American Geophysical Union