- Alt Name:
- Common wombat
- Specimen ID:
- Additional Media:
This is a model of the cranium of Vombatus ursinus, a grazing marsupial from Australia. The data was collected from CT scans of a road killed specimen collected under a research permit from the Victorian Department of Sustainability and Environment to receive and retain specimens of wildlife found dead from natural or accidental causes (Flora and Fauna Permit number 10005574). Sex: female
- A quantitative comparative analysis of the size of the frontoparietal sinuses and brain in vombatiform marsupials
- Sharp, A.C.
- Memoirs of Museum Victoria, 74, 331-342
Cranial sinuses result from the resorption and deposition of bone in response to biomechanical stress during a process known as pneumatisation. The morphology of a pneumatic bone represents an optimisation between strength and being light weight. The presence of very large sinuses has been described in a number of extinct marsupial megafauna, the size of which no longer exist in extant marsupials. With advances in digital visualisation, and the discovery of a number of exceptionally preserved fossil crania, a unique opportunity exists to investigate hypotheses regarding the structure and evolution of the atypically voluminous sinuses. Sinus function is difficult to test without first obtaining data on sinus variation within and between species. Therefore, the crania of seven species of extinct and extant vombatiform marsupials were studied using CT scans to provide a volumetric assessment of the endocast and cranial sinuses. Sinus volume strongly correlates with skull size and brain size. In the extinct, large bodied palorchestids and diprotodontids the sinuses expand around the dorsal and lateral parts of the braincase. Brain size scales negatively with skull size in vombatiform marsupials. In large species the brain typically fills less than one quarter of the total volume of the endocranial space, and in very large species, it can be less than 10%. Sinus expansion may have developed in order to increase the surface area for attachment of the temporalis muscle and to lighten the skull. The braincase itself would have provided insufficient surface area for the predicted muscle masses.
- Morphology of the Jaw-Closing Musculature in the Common Wombat ( Vombatus ursinus ) Using Digital Dissection and Magnetic Resonance Imaging
- Sharp, A.C., Trusler, P.W.
- PLoS ONE 10(2): e0117730. doi:10.1371/journal.pone.0117730
Wombats are unique among marsupials in having one pair of upper incisors, and hypsodont molars for processing tough, abrasive vegetation. Of the three extant species, the most abundant, the common wombat (Vombatus ursinus), has had the least attention in terms of masticatory muscle morphology, and has never been thoroughly described. Using MRI and digital dissection to compliment traditional gross dissections, the major jaw adductor muscles, the masseter, temporalis and pterygoids, were described. The masseter and medial pterygoid muscles are greatly enlarged compared to other marsupials. This, in combination with the distinctive form and function of the dentition, most likely facilitates processing a tough, abrasive diet. The broad, flat skull and large masticatory muscles are well suited to generate a very high bite force. MRI scans allow more detail of the muscle morphology to be observed and the technique of digital dissections greatly enhances the knowledge obtained from gross dissections.
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A quantitative comparative analysis of the size of the frontoparietal sinuses and brain in vombatiform marsupials
Morphology of the Jaw-Closing Musculature in the Common Wombat ( Vombatus ursinus ) Using Digital Dissection and Magnetic Resonance Imaging
Sharp & Trusler 2015 Wombat Jaw muscles.pdf