Maximucinus

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Maximucinus
Temporal range: Middle Miocene 14.2–12.9  Ma
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S
D
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Pg
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Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Infraclass: Marsupialia
Order: Dasyuromorphia
Family: Thylacinidae
Genus: Maximucinus
Species:
M. muirheadae
Binomial name
Maximucinus muirheadae
Wroe, 2001

Maximucinus is an extinct genus of thylacinid that lived during the Middle Miocene in what is now Queensland, Australia. It is known only a second upper molar found at the Riversleigh World Heritage Area. It was the largest thylacinid of its time, attaining a body size of 18 kg (40 lbs). The genus is monotypic, containing only one species, Maximucinus muirheadae.

Contents

History and naming

Maximucinus was described as a new genus and species of thylacinid in 2001 by Stephen Wroe. The holotype and only known specimen, catalogued as QM F30331, is an isolated second upper molar. It was collected from the Ringtail site at the Riversleigh World Heritage Area, north-western Queensland. [1] The site has been radiometrically dated to the Middle Miocene, ~14.2-12.9 Ma. [2]

The genus name combines the Latin word maximus, large, with kynos, the Ancient Greek word for dog. The species name was chosen to honour fellow researcher Jeanette Muirhead, for their contributions towards the study of fossil thylacinids. [1]

Description

Maximucinus is known only from a single specimen, an upper molar. Although the fossil material is scant, it has enough traits to differ it from all thylacinids. Stylar cusps B and D are well-developed. Furthermore, the aforementioned stylar cusps are compressed to the sides of the molar. The front most cingulum (a small shelf-like structure situated at the base of a tooth's crown) continues into the preparacrista. Both the protoconule and metaconule cusps are extremely small. [1]

Wroe (2001) estimated its weight to be 18 kg (40 lbs), making it the largest thylacinid discovered from the middle Miocene. [1]

Paleobiology

Fossils of Maximucinus are known only from a single site at Riversleigh, which dates to the Middle Miocene. [1] The climate during the Middle Miocene would have been warm and permanently wet. Open rainforests would have covered the landscape at the time. [2] [3] Coexisting alongside Maximucinus would have been the thylacinids Muribacinus and Nimbacinus , and the thylacoleonids Wakaleo oldfieldi , W. vanderleueri and Lekaneleo myersi . The two families of carnivorous marsupials were likely able to coexist with one another due to differences in both body size and vertical habitat segregation. [4]

The molar of Maximucinus shows some specializations towards hypercarnivory (i.e. minute protoconule and metaconule cusps), although it was clearly less specialised than that of later thylacinids as it still retains well-developed stylar cusps. [5]

Related Research Articles

<span class="mw-page-title-main">Peramelemorphia</span> Order of mammals

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<span class="mw-page-title-main">Thylacinidae</span> Extinct family of marsupials

Thylacinidae is an extinct family of carnivorous marsupials from the order Dasyuromorphia. The only species to survive into modern times was the thylacine, which became extinct in 1936.

<i>Thylacinus</i> Extinct genus of marsupials

Thylacinus is a genus of extinct carnivorous marsupials in the family Thylacinidae. The only recent member was the thylacine, commonly also known as the Tasmanian tiger or Tasmanian wolf. The last known Tasmanian tiger was in the Beaumaris Zoo in Tasmania, eventually dying in 1936. The earliest known member of the genus, Thylacinus macknessi appeared during the Early Miocene, around 16 million years ago, and was smaller than the modern thylacine, with a body mass of about 6.7–9.0 kilograms (14.8–19.8 lb). Thylacinus represented the only extant genus of the family after the beginning of the Pliocene around 5 million years ago. Over time members of the genus saw an increase in body mass and a greater adaption to hypercarnivory in their dental morphology.

Yalkaparidon is an extinct genus of Australian marsupials, first described in 1988 and known only from the Oligo-Miocene deposits of Riversleigh, northwestern Queensland, Australia.

<i>Badjcinus</i> Extinct genus of marsupials

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<i>Wakaleo</i> Extinct genus of marsupials

Wakaleo is an extinct genus of medium-sized thylacoleonids that lived in Australia in the Late Oligocene and Miocene Epochs.

<i>Ekaltadeta</i> Extinct genus of marsupials

Ekaltadeta is an extinct genus of marsupials related to the modern musky rat-kangaroos. Ekaltadeta was present in what is today the Riversleigh formations in Northern Queensland from the Late Oligocene to the Miocene, and the genus includes three species. The genus is hypothesized to have been either exclusively carnivorous, or omnivorous with a fondness for meat, based on the chewing teeth found in fossils. This conclusion is based mainly on the size and shape of a large buzz-saw-shaped cheek-tooth, the adult third premolar, which is common to all Ekaltadeta.

<i>Nimbacinus</i>

The genus Nimbacinus contains two species of carnivorous, quadrupedal marsupials in Australia both of which are extinct:

Nambaroo is an extinct genus of macropod marsupial from the late Oligocene to the early Miocene of Australia.

<i>Neohelos</i> Extinct genus of marsupials

Neohelos is an extinct diprotodontid marsupial, that lived from the early to middle-Miocene. There are four species assigned to this genus, Neohelos tirarensis, the type species, N. stirtoni, N. solus and N. davidridei. N. davidridei is the most derived species of the genus, and its premolar morphology shows that it is structurally and ancestor of the genus Kolopsis. All four species are from the Bullock Creek in the Northern Territory and Riversleigh of Australia.

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<i>Muribacinus</i> Extinct species of marsupial

Muribacinus gadiyuli lived during the middle Miocene in Riversleigh. The species name comes from Wanyi aboriginal word for "little", in reference to its considerably small size compared to the modern thylacine and was similar in size to a fox-terrier dog, and "father" for the ancestral characteristics of the fossilised teeth.

Mutpuracinus archibaldi is an extinct carnivorous, quadrupedal marsupial that lived during the middle Miocene and is the smallest known thylacinid at approximately 1.1 kilograms, the size of a quoll, though, more closely related to the recently extinct thylacine.

<i>Ngamalacinus</i> Extinct species of marsupial

Ngamalacinus is an extinct genus of thylacinid marsupial that lived during the late Oligocene and early Miocene of Australia. Fossils have been found in Riversleigh.

Wabulacinus ridei lived during the early Miocene in Riversleigh. It is named after David Ride, who made the first revision of thylacinid fossils. The material was found in system C of the Camel Spurtum assembledge.

The Macropodidae are an extant family of marsupial with the distinction of the ability to move bipedally on the hind legs, sometimes by jumping, as well as quadrupedally. They are herbivores, but some fossil genera like Ekaltadeta are hypothesised to have been carnivores. The taxonomic affiliations within the family and with other groups of marsupials is still in flux.

Joculusium muizoni is a fossil species discovered at the Riversleigh World Heritage Area. Little is known about the animal.

Liyamayi dayi is a mammal species of the Thylacomyidae family known from fossils located at the Riversleigh World Heritage Area in northeast Australia. The discovery of the specimens was identified as deposited around fifteen million years ago, revising the earliest record of this peramelemorphian lineage from those of species that existed around ten million years later.

Lekaneleo is a fossil genus of carnivorous marsupial that existed during the early Miocene in Australia. Once allied to the type species of the genus Priscileo, later placed as Wakaleo pitikantensis, "Priscileo" roskellyae was subsequently transferred to its own genus Lekaneleo.

Whollydooleya tomnpatrichorum is a fossil species discovered just beyond the Riversleigh World Heritage Area, an early example of adaptations to hypercarnivory. The dating of the deposit, while uncertain, is associated with material assigned to the genus Ekaltadeta, placing its occurrence in the middle or late Miocene epoch.

References

  1. 1 2 3 4 5 Wroe, S. (2001). "Maximucinus muirheadae, gen. et sp. nov. (Thylacinidae : Marsupialia), from the Miocene of Riversleigh, north-western Queensland, with estimates of body weights for fossil thylacinids". Australian Journal of Zoology. 49 (6): 603–314. doi:10.1071/ZO01044.
  2. 1 2 Woodhead, J.; Hand, S.J.; Archer, M.; Graham, I.; Sniderman, K.; Arena, D.A.; Black, K.H.; Godthelp, H.; Creaser, P.; Price, E. (2014). "Developing a radiometrically-dated chronologic sequence for Neogene biotic change in Australia, from the Riversleigh World Heritage Area of Queensland". Gondwana Research. 29 (1): 153–167. doi:10.1016/j.gr.2014.10.004.
  3. Travouillon, K.J.; Legendre, S.; Archer, M.; Hand, S.J. (2009). "Palaeoecological analyses of Riversleigh's Oligo-Miocene sites: implications for Oligo-Miocene climate change in Australia". Palaeogeography, Palaeoclimatology, Palaeoecology. 276 (1–4): 24–37. doi:10.1016/j.palaeo.2009.02.025.
  4. Gillespie, A. K. (2023). "Two new marsupial lion taxa (Marsupialia, Thylacoleonidae) from the early and Middle Miocene of Australia". Alcheringa: An Australasian Journal of Palaeontology. 47 (4): 506–521. Bibcode:2023Alch...47..506G. doi:10.1080/03115518.2022.2152096. S2CID   256157821.
  5. Rovinsky, Douglass S.; Evans, Alistair R.; Adams, Justin W. (2019-09-02). "The pre-Pleistocene fossil thylacinids (Dasyuromorphia: Thylacinidae) and the evolutionary context of the modern thylacine". PeerJ. 7: e7457. doi: 10.7717/peerj.7457 . ISSN   2167-8359. PMC   6727838 .