''Kudnu'' is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

neodiapsid Diapsids ("two arches") are a clade of sauropsids, distinguished from more primitive eureptiles by the presence of two holes, known as temporal fenestrae, in each side of their skulls. The earliest traditionally identified diapsids, the Araeosceli ...

reptile from the

Early Triassic The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between 251.9 Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic Series, which ...

Arcadia Formation of Australia. The type species is ''K. mackinlayi''.

Discovery and naming

The holotype is QM F9181, an anterior section of a cranium with articulated dentary rami, and it was discovered in the Crater, southwest of Rolleston, Queensland. The referred skull QM F9182 is also known. ''Kudnu mackinlayi'' was named and described by

Alan Bartholomai Alan Bartholomai AM (1938–2015) was a geologist and palaeontologist, and Director of the Queensland Museum from 1969–1999. Early life and education Alan Bartholomai was born on 31 December 1938 in Boonah, Queensland. He attended Boonah St ...

in 1979.

Classification

''Kudnu'' was initially classified within

Paliguanidae ''Paliguana'' is an extinct genus of lizard-like lepidosauromorph reptile. It is known from a single somewhat poorly preserved skull around in length from the earliest Triassic Katberg Formation (Beaufort Group) in the upper Lystrosaurus Assembl ...

by Bartholomai (1979). Benton (1985) classified ''Kudnu'' within

Lepidosauromorpha Lepidosauromorpha (in PhyloCode known as Pan-Lepidosauria) is a group of reptiles comprising all diapsids closer to lizards than to archosaurs (which include crocodiles and birds). The only living sub-group is the Lepidosauria, which contains tw ...

, while Evans (2003) classified ''Kudnu'' within

Prolacertiformes Protorosauria is an extinct, likely paraphyletic group of basal archosauromorph reptiles from the latest Middle Permian ( Capitanian stage) to the end of the Late Triassic ( Rhaetian stage) of Asia, Europe and North America. It was named by t ...

, and Evans & Jones (2010) later assigned ''Kudnu'' to the

Procolophonidae Procolophonidae is an extinct family (biology), family of small, lizard-like parareptiles known from the Late Permian to Late Triassic that were distributed across Pangaea, having been reported from Europe, North America, China, South Africa, Sou ...

. More recent authors, such as Poropat ''et al.'' (2023), consider ''Kudnu'' to be a basal member of Neodiapsida.

Paleoecology

The world ''Kudnu'' inhabited was still recovering from the recent

Permian–Triassic extinction event The Permian–Triassic extinction event (also known as the P–T extinction event, the Late Permian extinction event, the Latest Permian extinction event, the End-Permian extinction event, and colloquially as the Great Dying,) was an extinction ...

, and as a result global

biodiversity Biodiversity is the variability of life, life on Earth. It can be measured on various levels. There is for example genetic variability, species diversity, ecosystem diversity and Phylogenetics, phylogenetic diversity. Diversity is not distribut ...

had remained low throughout much of the

. The world at this time was generally a hot and arid

environment Environment most often refers to: __NOTOC__ * Natural environment, referring respectively to all living and non-living things occurring naturally and the physical and biological factors along with their chemical interactions that affect an organism ...

, reaching a temperature of 50 °C or even 60 °C at times. Currently a high diversity of

fauna Fauna (: faunae or faunas) is all of the animal life present in a particular region or time. The corresponding terms for plants and fungi are ''flora'' and '' funga'', respectively. Flora, fauna, funga and other forms of life are collectively ...

has so far been recorded from the Arcadia Formation that lived alongside ''Kudnu''. This includes a high diversity of

amphibians Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excl ...

including 14

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

, the

archosauriform Archosauriformes (Greek for 'ruling lizards', and Latin for 'form') is a clade of diapsid reptiles encompassing archosaurs and some of their close relatives. It was defined by Jacques Gauthier (1994) as the clade stemming from the last common anc ...

'' Kalisuchus rewanensis'', the

archosauromorph Archosauromorpha (Greek for "ruling lizard forms") is a clade of diapsid reptiles containing all reptiles more closely related to archosaurs (such as crocodilians and dinosaurs, including birds) than to lepidosaurs (such as tuataras, lizards, a ...

'' Kadimakara australiensis'', the

procolophonid Procolophonidae is an extinct family of small, lizard-like parareptiles known from the Late Permian to Late Triassic that were distributed across Pangaea, having been reported from Europe, North America, China, South Africa, South America, Antarc ...

'' Eomurruna yurrgensis'' as well as an indeterminate

dicynodont 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, t ...

. There is also evidence of a diversity of indermitae

ichnotaxa An ichnotaxon (plural ichnotaxa) is "a taxon based on the fossilized work of an organism", i.e. the non-human equivalent of an artifact. ''Ichnotaxon'' comes from the Ancient Greek (''íchnos'') meaning "track" and English , itself derived from ...

based on

coprolites A coprolite (also known as a coprolith) is fossilized feces. Coprolites are classified as trace fossils as opposed to body fossils, as they give evidence for the animal's behaviour (in this case, diet) rather than morphology. The name i ...

References

{{taxonbar, from1=Q124310734, from2=Q124310739 Diapsids Prehistoric reptile genera Induan genera Early Triassic reptiles Triassic vertebrates of Australia Mesozoic reptiles of Australia Fossil taxa described in 1979