|
The External Anatomy
of the Thylacine
The earliest
scientific descriptions of the thylacine (Paterson 1805), (Harris
1808), (Temminck 1824), focus almost exclusively on its external characteristics.
These early accounts provide us with detailed morphometric measurements
and descriptions of the dentition, the colour
and texture of the coat, and observations on the rhinarium (nose), feet,
ears, marsupium, and male genitalia. Contemporary German and French
commentaries tended to follow verbatim Harris's description. The
external anatomy section is a summary of these observations incorporating
current thinking and research. Thylacine reproduction is discussed under
a
separate
heading.
Facial features: |
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| The facial features
of the thylacine show several characteristics worthy of specific comment.
Harris (1808) states: "Head very large, bearing a near resemblance to
a wolf or hyaena". Temminck (1824) notes: "It is true, that
the lengthened shape of the muzzle and strong conical curved canines |
| give the head
of this animal a resemblance to that of dogs, but one can still notice
that independently of the disparity of the teeth, the zygomatics are much
more strongly arched than in any species of dog".
The male thylacine's
face is elongated and noticeably more wolf-like than that of the female,
whose face is generally shorter, with softer features. The muzzle
is narrow in comparison to the broad zygomatic
arch (cheek bone). The facial markings, including the
white blaze under the eyes, probably serve to highlight the direction of
the animal's gaze whilst hunting either as a pair, or in a larger family
group.
Reginald Innes Pocock
(1863-1947), was a British zoologist and superintendent of the London Zoo
from 1904 until |
.
.
. |
|
| his retirement in 1923. Pocock (1926)
published "The external characters of Thylacinus,
Sarcophilus and some related marsupials" in the Proceedings
of the Zoological Society, in which he gives the first comprehensive account
of the facial features of the thylacine. The paper was based upon
his examination of the bodies of a male and female thylacine in the prosectorium
(dissecting room) of the Zoological Society. |
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| Pocock opens his paper
by stating: |
.
| "Considerable attention
has been paid to the structure of the hind feet and marsupium in many of
the genera of the Polyprotodont
marsupials, but such organs as the rhinarium and the ears have been comparatively
neglected. Owing moreover to the rarity of Thylacinus and to its
large size, |
.
.
|
Reginald Innes Pocock
(1863-1947).
|
|
which
makes preservation of the body in alcohol a difficult matter, the feet
and other external parts have in great measure escaped detailed description.
Anatomists fortunate enough to secure fresh material from zoological gardens
paid attention mainly to the muscles or other internal organs".
Pocock then proceeds
to discuss the head with detailed reference to the facial vibrissae, the
rhinarium, and the ear.
Vibrissae (whiskers)
are specialised hairs usually employed for tactile sensation. Pocock
states with reference to the facial vibrissae of the thylacine:
"The reduction in
number and length
of the vibrissae in Thylacinus is to
be explained, probably in connection to its mode of life, as a cursorial
predatory marsupial which captures its prey to a great extent by speed
of foot in the open and not by stealthy creeping through thickets or in
the crannies of rocks, where the tactile sense of the vibrissae would be
especially useful". |
|
.
.
Lateral view of the
head of
Thylacinus, showing the facial vibrissae (colour-coded as
to type).
D. Kirshner (after Pocock
- Proceedings of the Zoological Society (1926) [Fig. 24 p. 1038]).
.
|
Superciliary
[supra orbital] (red) Mystacial
(blue) Submental
(yellow)
Interramal
(orange) Genal
(green) |
|
A. G. Lyne (1959), in
his paper: "The systematic and adaptive significance
of the vibrissae in the Marsupialia" published in the Proceedings
of the Zoological Society of London, gives the average number of facial
vibrissae in the thylacine as being 7 genal, 7 supraorbital, and 10 interramal,
and notes there is a profusion of mystacials on the upper lip.
William Paterson, in
a letter to Sir Joseph Banks dated 20th March 1805, makes reference to
the facial vibrissae: "On each side of the mouth are 19 bristles, length
of each 4 inches; and 6 bristles on each side under the ear, 9 on the lower
jaw upon each side, and 8 under the throat". |
