''Malerisaurus'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

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) rather than lepidosaurs (such as tuataras, l ...

known from

Andhra Pradesh Andhra Pradesh (, abbr. AP) is a state in the south-eastern coastal region of India. It is the seventh-largest state by area covering an area of and tenth-most populous state with 49,386,799 inhabitants. It is bordered by Telangana to the ...

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

and

Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...

of the

USA The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

Description

''Malerisaurus'' was a medium-sized archosauromorph which averaged 1.2 meters in length. ''Malerisaurus'' is known from the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...

ISIR 150, two

articulated An articulated vehicle is a vehicle which has a permanent or semi-permanent pivot joint in its construction, allowing it to turn more sharply. There are many kinds, from heavy equipment to buses, trams and trains. Steam locomotives were sometim ...

and almost complete skeletons which were discovered as the presumable gastric contents of two skeletons of ''

Parasuchus ''Parasuchus'' is an extinct genus of basal phytosaur known from the Late Triassic (late Carnian to early Norian stage) of Andhra Pradesh and Madhya Pradesh, India. At its most restricted definition, ''Parasuchus'' contains a single species, ' ...

hislopi''. It was collected from the

Lower Maleri Formation The Lower Maleri Formation is a sedimentary rock formation found in Andhra Pradesh and Telangana, India. It is the lowermost member of the Pranhita–Godavari Basin. It is of late Carnian to early Norian age (Upper Triassic), and is notable ...

, dating to the late

Carnian The Carnian (less commonly, Karnian) is the lowermost stage (stratigraphy), stage of the Upper Triassic series (stratigraphy), Series (or earliest age (geology), age of the Late Triassic Epoch (reference date), Epoch). It lasted from 237 to 227 m ...

or early Norian stage of the

Late Triassic The Late Triassic is the third and final epoch of the Triassic Period in the geologic time scale, spanning the time between Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch and followed by the Early Jurassic Epoch. ...

. ''Malerisaurus robinsonae'' was a small archosauromorph, probably capable of climbing trees and swimming. The skull has some adaptations to a carnivorous diet, but is nevertheless unspecialised and probably more of an insectivore. ''Malerisaurus'', seen as a

diapsid 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 group first appeared about three hundred million years a ...

skull, shows primitive and advanced facies in its unossified laterosphenoid, absence of antorbital and

mandibular fenestrae The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, th ...

, gracile form, primitive girdles, elongated cervicals and absence of dermal armour. Chatterjee (1980) assigned it to the suborder

Prolacertiformes Protorosauria is an extinct polyphyletic group of 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 the English anatom ...

, which currently represents four families: Sharovipterygidae, Protorosauridae, Prolacertidae and Tanystropheidae. Chatterjee provisionally regarded ''Malerisaurus'' as close to ''

Protorosaurus ''Protorosaurus'' ("first lizard") is a genus of lizard-like early reptiles. Members of the genus lived during the late Permian period in what is now Germany and Great Britain. Once believed to have been an ancestor to lizards, ''Protorosaurus'' ...

''. A second species, ''M. langstoni'', is known from the

TMM 31099-11, a partial but poorly preserved skeleton. It was collected in the Otis Chalk Quarry 2 (TMM 31099 locality) from the

Colorado City Formation The Colorado City Formation is a geologic formation in Texas, United States. It preserves fossils dating back to the Triassic period. Biochronological significance The Otis Chalk localities that are situated in the Colorado City Formation form ...

, Chinle Group, dating to the early

stage of the

, about 228–227.5

million years ago The abbreviation Myr, "million years", is a unit of a quantity of (i.e. ) years, or 31.556926 teraseconds. Usage Myr (million years) is in common use in fields such as Earth science and cosmology. Myr is also used with Mya (million years ago) ...

. It was found in the Howard County of Texas. Spielmann ''et al.'' (2006) redescribed the type material of ''M. langstoni'' and concluded that it's indistinguishable from the type species of ''

Trilophosaurus ''Trilophosaurus'' (Greek for "lizard with three ridges") is a lizard-like trilophosaurid allokotosaur known from the Late Triassic of North America. It was a herbivore up to 2.5 m long. It had a short, unusually heavily built skull, equipped wi ...

'', ''T. buettneri'', and thus ''M. langstoni'' represents its junior synonym.Spielmann, J.A., Lucas, S.G., Hunt, A.P., and Heckert. 2006
Reinterpretation of the holotype of ''Malerisaurus langstoni'', a diapsid reptile from the Upper Triassic Chinle Group of West Texas
''The Triassic-Jurassic Terrestrial Transition.'' New Mexico Museum of Natural History and Science, Bulletin 37:543-547. Nesbitt ''et al.'' (2017) reinterpreted ''Malerisaurus'' as an

allokotosauria Allokotosauria is a clade of early archosauromorph reptiles from the Middle to Late Triassic known from Asia, Africa, North America and Europe. Allokotosauria was first described and named when a new monophyletic grouping of specialized he ...

n archosauromorph belonging to the family

Azendohsauridae Azendohsauridae is a family of allokotosaurian archosauromorphs that lived during the Middle to Late Triassic period, around 242-216 million years ago. The family was originally named solely for the eponymous ''Azendohsaurus'', marking out its ...

. In 2021, Nesbitt ''et al.'' once again looked at ''Malerisaurus'', and found it to be an early-diverging, but late surviving, carnivorous azendohsaurid. This study also found ''M. langstoni'' to be a valid species of ''Malerisaurus''.

Etymology

''Malerisaurus'' was named by Sankar Chatterjee in 1980 and the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specime ...

is ''Malerisaurus robinsonae'' named in honour of the British Paleontologist who worked in India, Pamela Lamplugh Robinson. A second species, ''M. langstoni'', was named by him in

1986 The year 1986 was designated as the International Year of Peace by the United Nations. Events January * January 1 **Aruba gains increased autonomy from the Netherlands by separating from the Netherlands Antilles. **Spain and Portugal enter ...

. The generic name is derived from the name of the

, where the holotype of the type species was collected, and ''sauros'',

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

for "lizard". The specific name of ''M. langstoni'' honors the American paleontologist and professor Wann Langston, Jr.

References

{{Taxonbar, from=Q739142 Allokotosaurs Prehistoric reptile genera Late Triassic reptiles of Asia Late Triassic reptiles of North America Triassic India Fossils of India Triassic geology of Texas Paleontology in Texas Fossil taxa described in 1980