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The External Anatomy
of the Thylacine
Manus & pes: |
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| The thylacine is digitigrade,
meaning it normally walks on its toes. The feet of the thylacine
differ significantly from those of dasyurids (Pocock 1926). The pads
of the feet are granulated rather than striated. The front foot (manus)
has a small, largely non-functional thumb (pollex) which sometimes (although
rarely) will leave an imprint in tracks made in soft mud. Unlike
those of a dog, the |
| thylacine's
toes have no webbing between them. In canids, this webbing serves
to hold the digits together when running. In the thylacine, there
is a fusion of the three interdigital pads to form a single, tri-lobed
plantar pad. A long area of bare skin behind this pad separates it
from a carpal pad that is twice as long as it is wide. Hair encroaches
on the carpal region, but the skin around the plantar pad is devoid of
hair, and the creases between toes 2, 3 and 4 appear granular. Ground
contact is made by the digital pads on the tips of the toes and the anterior
area of the plantar pad. Finely pointed papillae
(tiny skin projections which aid in traction) cover these pads. |
| Click
the microscope icon for a magnified view of: papillae. |
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Temminck (1824) states:
"The toes of the
feet are hidden under a long and hard hair of a yellowish white, there
are five toes on the front limbs and four on the hind limbs, all armed
with strong blunt nails".
The naked skin between
digits 2 through 4 of the thylacine's front feet is highly glandular (Pocock
1926), resulting in an easily identified spoor.
The thylacine has five digital pads on
the front foot and four on the rear foot. Its claws are non-retractile. |
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Pes (hind foot) of the
thylacine, showing hair covering the toes.
Source: International Thylacine
Specimen Database, 5th Revision 2013.
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Michael Sharland (1939), in his paper: "In Search of the Thylacine",
published in the Proceedings of the Zoological Society of New South Wales,
makes comment on the unique tracks of the thylacine when compared to those
of a domestic dog.
Sharland states:
"The feet of the
thylacine have been likened to dogs' but the resemblance is superficial
only. The manus or hand of the thylacine leaves a distinct impression
in which five digits and claws are generally visible. The digits
are arranged on about the same plane, and moreover are fairly evenly spaced,
so that when the hand is pressed into mud or soft soil, all are clearly
to be seen. In the imprint of a dog's hand, however, the marks of
only four digits are visible, the fifth digit being situated about an inch
above the level of the others, does not reach the mud unless this be soft
enough to cause the limb to sink to the elbow. An ordinary impression
of a dog on the track therefore shows only four digits and claws, so the
identification is simple and should not be confused with a thylacine.
But in the pes, or true feet, of thylacine - the hind feet - only four
digits are present, the hallux or big toe being absent". |
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Thylacine manus (hand)
with splayed toes. Source: The external characteristics of Thylacinus,
Sarcophilus and some related marsupials, R. I. Pocock - PZSL 1926 Vol.
2 Fig. 33 (A).
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Palmar view of thylacine
manus showing pad detail, with a comparison to an illustration by Pocock
(1926).
Courtesy: Oxford University
Museum of Natural History. Specimen Skin OUM7934.
Source: International Thylacine
Specimen Database, 5th Revision 2013.
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| The pes
or hind foot of the thylacine is much longer than the manus.
There is no hallux (the foot's first digit - analogous to the thumb of
the hand), and the four remaining toes are long and un-webbed. There
is a single plantar pad which is bi-lobed posteriorly, but without any
trace of a pad behind it. Instead, hair encroaches on the heel, leaving
a long and narrow patch of naked skin that reaches to the end of the heel. |
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Plantar view of the
pes (hind foot) of the thylacine (wet specimen). Courtesy: Grant
Museum of Zoology (University College, London). Photo: Dr. Stephen
Sleightholme.
Source: International Thylacine
Specimen Database, 5th Revision 2013.
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Lateral view of the
pes (hind foot) of the thylacine by D. Kirshner (after Pocock 1926).
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Temminck (1824) makes
the following remark about the hind foot, and the thylacine's ability to
adopt a kangaroo-type stance: "This animal, largest of the marsupial
carnivores is to be judged by some by the naked lower part of the heel;
it appears that it is accustomed to often supporting all the plant of the
posterior feet". |
