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| The molars are flattened
and triangular, with jagged edges that function like serrated-edged blades.
The premolars and molars of the thylacine are adapted to slicing and crushing,
and lack pronounced grinding surfaces, as is the case in canids.
In comparing the skull of a thylacine with that of a placental carnivore,
one of the evolutionary similarities is in the carnassial (=sectorial)
teeth, |
| the
broad, blade-like teeth in both the upper and lower jaws that act like
scissors to slice flesh. In all placental carnivores, it is the last
upper premolar and the first lower molar so modified. The other molars
are reduced in size and act as crushing teeth. In contrast, it is
the last four molar teeth in both jaws of the thylacine that are modified
as carnassials. Clearly, the carnassials of placental carnivores
and the thylacine are not homologous. In addition, the skull of the
thylacine has four molars (placentals never have more than three) and only
three premolars (placentals have up to four). |
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Upper molar tooth detail.
Photo: International Thylacine Specimen Database 5th Revision 2013.
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Upper and lower molars
(lateral view).
Specimen IRSNB 31E.
Courtesy: Institut Royal des Sciences Naturelles de Belgique.
Photo: International Thylacine
Specimen Database 5th Revision 2013.
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| Carnivores
with a high proportion of meat in their diet have longer relative cutting
blade lengths and smaller relative grinding areas in their molar tooth
row (Van Valkenburgh 1989). The thylacine's molar teeth are intermediate
in grinding and slicing function, and are quite slender, with no indications
of adaptation for bone consumption. When closing the lower jaw, the
thylacine's blade-like molars pass each other in a slicing fashion, which
is extremely effective at shearing meat from bone. The rear molars
have a greater grinding surface area and a smaller cutting edge, whereas
the front molars have a smaller grinding surface and a greater cutting
edge. |
| Click
the film icon above to view a 3D computer animation of the thylacine's
dentition. |
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Thylacine molar grind
surface to cutting edge ratio. C+ Increased cutting edge, C- Decreased
cutting edge, G+ Increased grinding surface, G- Decreased grinding surface.
Specimen OUM 4800.
Courtesy: Oxford University Museum.
Photo: International Thylacine
Specimen Database 5th Revision 2013.
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