''Malerisaurus'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

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, liza ...

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 language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

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 Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

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 several ...

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 someti ...

and almost complete

skeleton A skeleton is the structural frame that supports the body of an animal. There are several types of skeletons, including the exoskeleton, which is the stable outer shell of an organism, the endoskeleton, which forms the support structure inside ...

s 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 geological formation, 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 Triassi ...

, dating to the late

Carnian The Carnian (less commonly, Karnian) is the lowermost stage of the Upper Triassic Series (or earliest age of the Late Triassic Epoch). It lasted from 237 to 227 million years ago (Ma). The Carnian is preceded by the Ladinian and is followed by t ...

or early

Norian The Norian is a division of the Triassic Period. It has the rank of an age (geochronology) or stage (chronostratigraphy). It lasted from ~227 to million years ago. It was preceded by the Carnian and succeeded by the Rhaetian. Stratigraphic defi ...

stage of the

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

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, the ...

, 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 anatomis ...

, 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

. 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 The Chinle Formation is an Upper Triassic continental geological formation of fluvial, lacustrine, and palustrine to eolian deposits spread across the U.S. states of Nevada, Utah, northern Arizona, western New Mexico, and western Colorado. In Ne ...

, 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 The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linna ...

.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 herbivor ...

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 Events January * January 4 – U.S. President Jimmy Carter proclaims a grain embargo against the USSR with the support of the European Commission. * January 6 – Global Positioning System time epoch begins at 00:00 UTC. * January 9 – ...

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 specimen ...

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 ente ...

. 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 Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

of ''M. langstoni'' honors the American paleontologist and professor

Wann Langston, Jr. Wann Langston Jr. (1921 – April 7, 2013) was an American paleontologist and professor at the University of Texas at Austin. Langston worked on a number of different reptiles and amphibians in his long career, beginning with the 1950 description ...

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