Muribacinus
{{Short description|Extinct species of marsupial}}
{{speciesbox
| fossil_range = middle Miocene, {{fossilrange| 15.1-12.9}}
| image = Muribacinus gadiyuli.png
| image_caption = Holotype and paratype specimens of Muribacinus.
| taxon = Muribacinus gadiyuli
| authority = Wroe, 1995
}}
Muribacinus is an extinct genus of thylacinid that lived during the middle Miocene in what is now northwestern Queensland, Australia. It was described in 1995 from remains collected at the Riversleigh World Heritage Area. Only one species is known, M. gadiyuli.
History and naming
File:Riversleigh_Fossil_Site_-_panoramio_(14).jpg
Muribacinus was named in 1995 by Stephen Wroe based on fossils recovered from the Riversleigh World Heritage Area, northwestern Queensland. The holotype, QMF 30836, is a partial right maxilla and jugal collected from the Gag site. A right dentary from Henk’s Hollow site was assigned to the genus based on the proportions of the molar's shearing crests.{{cite journal |last1=Wroe |first1=Stephen |title=Muribacinus gadiyuli (Thylacinidae: Marsupialia), a very plesiomorphic thylacinid from the Miocene of Riversleigh, northwestern Queensland, and the problem of paraphyly for the Dasyuridae (Marsupialia) |journal=Journal of Paleontology |date=1995 |volume=70 |issue=6 |pages=1032–1044 |doi=10.1017/S0022336000038737|s2cid=131861751 }}
The generic name is a combination of the Waanyi word "muriba" (father) and the Ancient Greek stem word "-kynos" (dog), for the assumed classification as an early thylacinid species. The specific name comes from the Waanyi word “gadiyuli” (little).
Description
Although smaller than most thylacinids, Muribacinus would have been similar in size to the modern Tiger quoll. Wroe (2001) estimated its weight to have been 1.6 kg (3.5 lbs), while Rovinsky et al. (2019) gave it a slightly larger estimate of 1.6–1.7 kg (3.5-3.7 lbs).{{cite journal |last1=Wroe |first1=S. |authorlink1=S. W. Wroe |title=Maximucinus muirheadae, gen. et sp. nov. (Thylacinidae : Marsupialia), from the Miocene of Riversleigh, north-western Queensland, with estimates of body weights for fossil thylacinids |journal=Australian Journal of Zoology |date=2001 |volume=49 |issue=6 |pages=603–314 |doi=10.1071/ZO01044}}{{Cite journal |last=Rovinsky |first=Douglass S. |last2=Evans |first2=Alistair R. |last3=Adams |first3=Justin W. |date=2019-09-02 |title=The pre-Pleistocene fossil thylacinids (Dasyuromorphia: Thylacinidae) and the evolutionary context of the modern thylacine |url=https://peerj.com/articles/7457 |journal=PeerJ |language=en |volume=7 |pages=e7457 |doi=10.7717/peerj.7457 |issn=2167-8359|doi-access=free |pmc=6727838 }}
The teeth of Muribacinus retain large protocone cusps and talonids. The paracone and metacone cusps have a large distance between them. On each molar, the metaconid cusps and the small shelf that runs along the labial side of the tooth (called the stylar shelf) aren't as small as in other thylacinids. The second premolar is larger than the third premolar. The crest in front of the paracone (known as the preparacrista) is longer relative to the lingual border of the metacone (postmetacrista) on the second and third molars.
Classification
The first phylogenetic analysis that included Muribacinus found it to be in a polytomy with Mutpuracinus, Nimbacinus and clade containing all other thylacinids.B. Wroe S. 2003. "Australian marsupial carnivores: recent advances in palaeontology." In: Jones M, Dickman C, Archer M, eds. Predators with Pouches: The Biology of Carnivorous marsupials. Collingwood: CSIRO Publishing. 102-123 Subsequent studies throughout the years have, however, recovered conflicting results. Both Murray & Megirian (2000) and Yates (2015) have recovered as the basalmost member of Thylacinidae.{{cite journal |last1=Murray |first1=P. |last2=Megirian |first2=D. |title=Two New Genera and Three New Species of Thylacinidae (Marsupialia) from the Miocene of the Northern Territory, Australia |journal=The Beagle: Occasional Papers of the Northern Territory Museum of Arts and Sciences |date=2000 |volume=16 |pages=145–162 |url=https://www.biodiversitylibrary.org/part/254543}}{{cite journal |last1=Yates |first1=A.M. |authorlink1=Adam M. Yates |title=Thylacinus (Marsupialia: Thylacinidae) from the Mio-Pliocene boundary and the diversity of Late Neogene thylacinids in Australia |journal=PeerJ |date=12 May 2015 |volume=3 |pages=e931 |doi=10.7717/peerj.931|pmid=26019996 |pmc=4435473 |doi-access=free }} In at least two phylogenetic analyses performed by Rovinsky et al. (2019), Muribacinus formed a minor clade with the early-middle Miocene taxa Ngamalacinus and Nimbacinus as a sister group to all other thylacinids.
{{Clade|{{Clade
|label1=Thylacinidae
|1={{clade |1=Badjcinus turnbulli
|2={{Clade
|1={{Clade
|2={{Clade
|1=Muribacinus gadiyuli
}} }}
|2={{Clade
|2={{Clade
|label2=Thylacinus
|2={{Clade
|2={{Clade
|2={{Clade
}} }} }} }} }} }} }} }}}}
In at least one phylogenetic analysis performed by Churchill et al. (2024), Muribacinus was found to be a non-thylacinid dasyuromorphian, specifically within a polytomy with a well supported clade containing Barinya, Tyarrpecinus, Myrmecobius and Dasyuridae.{{cite journal |last1=Churchill |first1=T. J. |last2=Archer |first2=M. |last3=Hand |first3=S. J. |title=Three new thylacinids (Marsupialia, Thylacinidae) from late Oligocene deposits of the Riversleigh World Heritage Area, northwestern Queensland |journal=Journal of Vertebrate Paleontology |date=2024 |doi=10.1080/02724634.2024.2384595|doi-access=free }}
Paleobiology
Although not directly dated, both the Gag site and Henk’s Hollow site are thought to have been middle Miocene in age, with a date range of ~15.1 to 12.9 Ma. During this time, Australia's climate would have been relatively warmer and wetter than it is today.{{Cite journal|last1=Woodhead|first1=J.|last2=Hand|first2=S.J.|last3=Archer|first3=M.|last4=Graham|first4=I.|last5=Sniderman |first5=K.| last6=Arena| first6=D.A.|last7=Black|first7=K.H.|last8=Godthelp|first8=H.|last9=Creaser|first9=P.|last10=Price|first10=E.|year=2014|title=Developing a radiometrically-dated chronologic sequence for Neogene biotic change in Australia, from the Riversleigh World Heritage Area of Queensland.|journal=Gondwana Research|volume=29|issue=1|pages=153-167|doi=10.1016/j.gr.2014.10.004|hdl=1959.4/unsworks_36975|hdl-access=free}} The terrestrial biome of Riversleigh at the time has been interpreted as either being open forest or rainforest.{{Cite journal|last1=Travouillon|first1=K.J.|last2=Legendre|first2=S.|last3=Archer|first3=M.|last4=Hand|first4=S.J.|year=2009|title=Palaeoecological analyses of Riversleigh's Oligo-Miocene sites: implications for Oligo-Miocene climate change in Australia.|journal=Palaeogeography, Palaeoclimatology, Palaeoecology|volume=38|issue=4|pages=24-37|doi=10.1016/j.palaeo.2009.02.025}}
Contemporaneous with Muribacinus was the medium-sized, hypercarnivorous thylacinid Wabulacinus macknessi, and the small to medium-sized thylacoleonids Wakaleo oldfieldi and Lekaneleo myersi.{{cite journal |last1=Muirhead |first1=J. |last2=Gillespie |first2=A.K. |title=Additional Parts of The Type Specimen of Thylacinus macknessi (Marsupialia: Thylacinidae) From Miocene Deposits of Riversleigh, Northwestern Queensland. |journal=Australian Mammalogy |date=1995 |volume=18 |issue=1 |pages=55–60|url=http://www.create.unsw.edu.au/research/files/!Muirhead%20&%20Gillespie%20(1995)%20ADDITIONAL%20PARTS%20OF%20THE%20TYPE%20SPECIMEN%20OF%20THYLACINUS%20MACKNESSI.pdf}}{{Cite journal|last1=Gillespie|first1=A. K.|last2=Archer|first2=M.|last3=Hand|first3=S.J.|last4=Black|first4=K. H. |title=New material referable to Wakaleo (Marsupialia: Thylacoleonidae) from the Riversleigh World Heritage Area, northwestern Queensland: revising species boundaries and distributions in Oligo/ Miocene marsupial lions|journal=Alcheringa: An Australasian Journal of Palaeontology|date=2014|volume=38|issue=4|pages=513–527|doi=10.1080/03115518.2014.908268|hdl=1959.4/unsworks_36969|hdl-access=free}} Differences in body size and vertical segregation have been suggested to have reduced competition between the two families.{{cite journal |last1=Gillespie |first1=A. K. |title=Two new marsupial lion taxa (Marsupialia, Thylacoleonidae) from the early and Middle Miocene of Australia |journal=Alcheringa: An Australasian Journal of Palaeontology |date=2023 |volume=47 |issue=4 |pages=506–521 |doi=10.1080/03115518.2022.2152096|bibcode=2023Alch...47..506G |s2cid=256157821 }} As a result of its pronounced metaconid cusps, Muribacinus is thought to have been an unspecialised faunivore that fed on small vertebrates and invertebrates.
References
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{{Agreodontia}}
{{Taxonbar|from=Q4457156}}
Category:Prehistoric thylacines