Eomurruna

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Eomurruna
Temporal range: Early Triassic,
~251–247  Ma
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Reconstructed skeletal diagram of Eomurruna yurrgensis
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Parareptilia
Order: Procolophonomorpha
Family: Procolophonidae
Subfamily: Theledectinae
Genus: Eomurruna
Hamley, Cisneros & Damiani, 2020
Species:
E. yurrgensis
Binomial name
Eomurruna yurrgensis
Hamley, Cisneros & Damiani, 2020

Eomurruna is a genus of procolophonid reptile that existed in what is now Queensland, Australia during the Early Triassic period (247-251 Mya). The genus is made up of a single species, E. yurrgensis, originally uncovered within the Arcadia Formation in 1985. Since then over 40 specimens have been referred to the genus, making Eomurruna one of the most complete organisms so far found from the Mesozoic of Australia. [1]

Contents

Discovery and naming

Holotype Eomurruna holotype-removebg-preview.png
Holotype

Eomurruna was originally discovered on the basis of an articulated skeleton (QMF 59501), only missing various digits of each foot, gastralia as well as half of the tail. QMF 59501 was originally collected by Ruth Lane in 1985 within the Arcadia Formation. From here on more specimens would be referred to the genus; today there are over 40 specimens that have been referred to the genus, making Eomurruna one of the most complete and well understood animals from Mesozoic of Australia. It wasn't until 35 years later that the genus would receive a proper scientific description and a name.

The generic name is a combination of the Ancient Greek ἠώς, eos, dawn, and murruna, the name of the extant shingleback skink in the Bidyara language of Queensland. The specific name is derived from the Bidyara yurrga, a hole within the Earth and the Latin suffix ensis meaning "of" or "belonging to" which is a reference to where the majority of specimens have been found.

Description

Referred skull Eomurruna skull.png
Referred skull

Eomurruna represents a small, lizard-like organism, only reaching a length of 175mm. It possessed a very short tail, a long flat body as well as enlarged bulbous teeth, a feature not often seen among procolophonids. Eomurruna represents an intermediate stage between a more primitive tooth pattern seen in owenettids, whereas the lower teeth abduct near the side of the tongue, resulting in no tooth-to-tooth collision between the upper and lower teeth. This trait is seen within most horned procolophonids, as an adaptation for herbivory. [2] Because of this we can say with safety that Eomurruna feed mainly of fibrous, low-lying vegetation as well as (most-likely) occasionally feeding on small invertebrates such as insects.

In four individuals (QMF 6693, QMF 49497, QMF 49508 and QMF 49511) evidence for tooth replacement is present, adding more support for the hypothesis that procolophonids had a low rate of tooth replacement. [3]

Paleoecology

The world Eomurruna inhabited was still recovering from the recent Permian–Triassic extinction event, and as a result global biodiversity had remained low throughout much of the Early Triassic. [4] The world at this time was generally a hot and arid Environment, reaching a temperature of 50 °C or even 60 °C at times. [5]

Currently a high diversity of fauna has so far been recorded from the Arcadia Formation that lived alongside Eomurruna. This includes a high diversity of amphibians including 14 genera, [6] the archosauriform Kalisuchus rewanensis , [7] the archosauromorph Kadimakara australiensis , [8] the lizard Kudnu mackinlayi [9] as well as an indeterminate Dicynodont. [10]

There is also evidence of a diversity of indermitae ichnotaxa based on coprolites. [11]

Related Research Articles

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Dicynodontia is an extinct clade of anomodonts, an extinct type of non-mammalian therapsid. Dicynodonts were herbivores that typically bore a pair of tusks, hence their name, which means 'two dog tooth'. Members of the group possessed a horny, typically toothless beak, unique amongst all synapsids. Dicynodonts first appeared in Southern Pangaea during the mid-Permian, ca. 270–260 million years ago, and became globally distributed and the dominant herbivorous animals in the Late Permian, ca. 260–252 Mya. They were devastated by the end-Permian Extinction that wiped out most other therapsids ca. 252 Mya. They rebounded during the Triassic but died out towards the end of that period. They were the most successful and diverse of the non-mammalian therapsids, with over 70 genera known, varying from rat-sized burrowers to elephant-sized browsers.

<i>Shonisaurus</i> Extinct genus of reptiles

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<i>Procolophon</i> Extinct genus of reptiles

Procolophon is a genus of lizard-like procolophonid parareptiles that first appeared in the Early Triassic (Induan) of South Africa, Brazil, and Antarctica. It persisted through the Permian–Triassic extinction event, but went extinct in the beginning of the Early Middle Triassic. The type species is P. trigoniceps.

<i>Leptopleuron</i> Extinct genus of reptiles

Leptopleuron is an extinct genus of procolophonid that lived in the dry lands during the late Triassic in Elgin of northern Scotland and was the first to be included in the clade of Procolophonidae. First described by English paleontologist and biologist Sir Richard Owen, Leptopleuron is derived from two Greek bases, leptos for "slender" and pleuron for "rib," describing it as having slender ribs. The fossil is also known by a second name, Telerpeton, which is derived from the Greek bases tele for "far off" and herpeton for "reptile." In Scotland, Leptopleuron was found specifically in the Lossiemouth Sandstone Formation. The yellow sandstone it was located in was poorly lithified with wind coming from the southwest. The environment is also described to consist of barchan dunes due to the winds, ranging up to 20 m tall that spread during dry phases into flood plains. Procolophonoids such as Leptopleuron were considered an essential addition to the terrestrial ecosystem during the Triassic.

<i>Clevosaurus</i> Extinct genus of reptiles

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<i>Arcadia myriadens</i> Extinct genus of amphibians

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<i>Eosimops</i> Extinct genus of dicynodonts

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<i>Acleistorhinus</i> Extinct genus of reptiles

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<span class="mw-page-title-main">Prolacertidae</span> Extinct family of reptiles

Prolacertidae is an extinct family of archosauromorph reptiles that lived during the Early Triassic epoch. It was named in 1935 by the British palaeontologist Francis Rex Parrington to include the species Prolacerta broomi of South Africa and Antarctica. In 1979 a second species, Kadimakara australiensis, was described from Australia. Several other genera, such as Macrocnemus, Pamelaria and Prolacertoides, have also been assigned to this family in the past, but these have been placed elsewhere by later studies, leaving Prolacerta and Kadimakara as the only well-supported members.

Palacrodon is an extinct genus of Triassic reptile with a widespread distribution. It was initially described from teeth collected in Early Triassic deposits in South Africa, and later reported from the Early Triassic of Antarctica and the Late Triassic of Arizona. Although previously considered an early rhynchocephalian, it is currently considered to be a non-saurian neodiapsid.

<i>Kadimakara australiensis</i> Extinct species of reptile

Kadimakara is an extinct genus of early archosauromorph reptile from the Arcadia Formation of Queensland, Australia. It was seemingly a very close relative of Prolacerta, a carnivorous reptile which possessed a moderately long neck. The generic name Kadimakara references prehistoric creatures from Aboriginal myths which may have been inspired by ice-age megafauna. The specific name K. australiensis relates to the fact that it was found in Australia. Prolacerta and Kadimakara were closely related to the Archosauriformes, a successful group which includes archosaurs such as crocodilians, pterosaurs, and dinosaurs.

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This list of fossil reptiles described in 2021 is a list of new taxa of fossil reptiles that were described during the year 2021, as well as other significant discoveries and events related to reptile paleontology that occurred in 2021.

<i>Kudnu</i> Extinct genus of reptiles

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References

  1. Hamley, Tim; Cisneros, Juan; Damiani, Ross (2020). "A procolophonid reptile from the Lower Triassic of Australia". Zoological Journal of the Linnean Society. 192 (2): 554–609. doi:10.1093/zoolinnean/zlaa056.
  2. Colbert; Edwin, Harris (1946). "Hypsognathus, a Triassic reptile from New Jersey". Bulletin of the American Museum of Natural History. hdl:2246/390.
  3. Ivakhnenko, M. F. (1974). "New data on Early Triassic procolophonids of the USSR". Paleontological Journal. 8: 346–351.
  4. Sahney, S.; Benton, M.J. (2008). "Recovery from the most profound mass extinction of all time". Proceedings of the Royal Society B: Biological Sciences. 275 (1636): 759–65. doi:10.1098/rspb.2007.1370. PMC   2596898 . PMID   18198148.
  5. Marshall, Michael (18 October 2012). "Roasting Triassic heat exterminated tropical life".
  6. M. H, Monroe. "The Triassic Labyrinthodonts of Australia". Australia: The Land Where Time Began. M. H Monroe.
  7. Thulborn, R. A. (1979). "A proterosuchian thecodont from the Rewan Formation of Queensland". Memoirs of the Queensland Museum. 19: 331–355.
  8. Alan, Bartholomai (2008). "New lizard-like reptiles from the Early Triassic of Queensland". Alcheringa: An Australasian Journal of Palaeontology. 3 (3): 225–234. doi:10.1080/03115517908527795.
  9. Alan, Bartholomai (2008). "New lizard-like reptiles from the Early Triassic of Queensland". Alcheringa: An Australasian Journal of Palaeontology. 3 (3): 225–234. doi:10.1080/03115517908527795.
  10. Rozefelds, Andrew C.; Warren, Anne; Whitfield, Allison; Bull, Stuart (2011). "New Evidence of Large Permo-Triassic Dicynodonts (Synapsida) from Australia". Journal of Vertebrate Paleontology. 31 (5): 1158–1162. doi:10.1080/02724634.2011.595858. S2CID   140599970.
  11. Caroline, Northwood (2005). "Early Triassic coprolites from Australia and their palaeobiological significance". The Journal of the Palaeontological Association. doi:10.1080/02724634.2011.595858. S2CID   140599970.