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BIOLOGY:
- ANATOMY -
EXTERNAL ANATOMY (page 8)
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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.

pes (hind foot) of the thylacine
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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".

thylacine manus with splayed toes - Pocock (1926)
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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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thylacine right hand (manus) - image  Dr. Stephen Sleightholme
thylacine right hand (manus) - Pocock (1926)
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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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pes (hind foot) of the thylacine - image  Dr. Stephen Sleightholme
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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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pes (hind foot) of the thylacine - D. Kirshner (after Pocock 1926)
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Lateral view of the pes (hind foot) of the thylacine by D. Kirshner (after Pocock 1926).

    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".

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References
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back to: External Anatomy (page 7) return to the subsection's introduction forward to: External Anatomy (page 9)


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