Thylacine skull

Introduction:

In the Alfred Denny Museum we hold the skull of a thylacine, which is currently on display in our cabinet display about Colonialism and the museum. The skull is presumed to have been purchased from Henry Denny (Alfred's Father) while Alfred was gathering specimens to establish a museum.

Henry Denny had an extensive collection of thylacine specimens rumoured to be larger than that of the Natural History Museum which he acquired for the Leeds City Museum from Tasmania during the late 19th century through contacts with landowners in Cleveland and naturalists such as Morton Allport.

Thylacine skull at the Alfred Denny Museum

Taxidermy thylacine at the Natural History Museum in ViennaBy GoleGole - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=23233000

What is a thylacine?

The thylacine (Thylacinus cynocephalus) is an extinct marsupial carnivore that was native to the Australian mainland and islands of Tasmania in New Guinea. It went extinct in New Guinea and Mainland Australia around 3600-3200 years ago possibly due to the introduction of the dingo. Around 5000 thylacines remained in the wild in Tasmania until the arrival of European colonial settlers in the beginning of the 19th century. Settlers viewed the thylacine as a pest and threat to their livestock farms and thus bounty hunting was introduced, leading to widespread population decline. Additional factors contributed to the decline and eventual extinction of the thylacine including competition with introduced wild dogs, loss of habitat, low-genetic diversity and disease.

By the 20th century thylacines were increasingly rare, which resulted in increased demand for captive specimens for zoos as well as skins, skeletons and preserved specimens for private collectors and museums -adding additional pressure to the already vulnerable small population. The last known surviving thylacine was a captive adult male at Hobart Zoo which passed away in September 1936 making the species completely extinct.

Use of the skull

During 2023-24 there have been two research projects using the thylacine skull at the University of Sheffield:

Morphological assessment to determine levels of convergent evolution between the thylacine and other mammalian carnivores
A genomics project involving DNA phylogenetic analysis of thylacine teeth to confirm which population the skull came from

The skull is also used as an example of wider impacts of colonialism on animal populations/ecosystems on our monthly tours and features in undergraduate requirement at the University to highlight the importance of museum collections in research and introduce prospective students to the Alfred Denny Museum.

Skull analysis BSC research project

Hannah, an undergraduate student supervised by Gavin Thomas, conducted a project looking for evidence of convergent evolution (where distantly related organisms evolve similar features due to similar adaption pressures) between the thylacine and other placental mammals.

Thylacine facial structures look similar to many of today's canid species, despite last sharing a common ancestor over 160 million years ago, possibly due to convergent evolution as they play similar roles as apex predators in their respective ecosystem.

Hannah 3D scanned the thylacine skull and measured it then compared the measurements with published cranial data for 60 other species including other marsupials, felids, canids and a few other mammals.

She found that the thylacine shared more similarities with the grey wolf (Canis lupus) than any other species compared, despite the thylacine being more phylogenetically close to marsupial species. She also found no evidence for convergence with felids.

3D scan of the upper skull

Genomics analysis MBiol research project

Anna, an integrated masters student supervised by Jon Slate, extracted a portion of DNA from some of the thylacine teeth and carried out next generational sequencing which allowed her to assemble the mitochondrial genome and perform a phylogenetic analysis.

This analysis confirmed that (a) the skull is indeed a thylacine and (b) it came from the Tasmanian population rather than the mainland Australian population which used to extend as far North as Papua New Guinea.

The tooth DNA extraction was carried out in DNA cleanrooms recently built for museum-omics projects at the NERC Environmental Omics Faculty (NEOF) at the University.

There are future plans to assemble the entire genome of the thylacine which can be used to infer more information about past population sizes.

Project workflow taken from Anna's research poster.

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