''Malerisaurus'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

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 ...

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 ...

known from

Telangana Telangana is a States and union territories of India, state in India situated in the Southern India, south-central part of the Indian subcontinent on the high Deccan Plateau. It is the List of states and union territories of India by area, ele ...

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

and

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

of the

USA The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 states and a federal capital district, Washington, D.C. The 48 contiguous ...

Description

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

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

ISIR The International Society for Intelligence Research (ISIR) is a scientific society for researchers in human intelligence. It was founded by Douglas K. Detterman of Case Western Reserve University in 2000. The society advocates for ongoing suppo ...

150, two

articulated An articulated vehicle is a vehicle which has a permanent or semi-permanent coupling in its construction. This coupling works as a large pivot joint, allowing it to bend and turn more sharply. There are many kinds, from heavy equipment to buse ...

and almost complete

skeleton A skeleton is the structural frame that supports the body of most animals. There are several types of skeletons, including the exoskeleton, which is a rigid outer shell that holds up an organism's shape; the endoskeleton, a rigid internal fra ...

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 (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 227.3 ...

or early

Norian The Norian is a division of the Triassic geological period, Period. It has the rank of an age (geology), age (geochronology) or stage (stratigraphy), stage (chronostratigraphy). It lasted from ~227.3 to Mya (unit), million years ago. It was prec ...

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 a ...

. ''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 earliest traditionally identified diapsids, the araeosc ...

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

mandibular fenestrae The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

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

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 ...

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

Protorosaurus ''Protorosaurus'' (from , 'earlier' and , 'lizard') is an extinct genus of reptile. 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, ''Protoro ...

''. 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 Late Triassic Formation (geology), geologic formation in the Dockum Group of Texas, United States. It has previously been known as the Iatan Member, Colorado City Member or 'Pre-Tecovas Horizon' (as it is assumed ...

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 ...

, dating to the early

stage of the

, about 228–227.5

million years ago Million years ago, abbreviated as Mya, Myr (megayear) or Ma (megaannum), is a unit of time equal to (i.e. years), or approximately 31.6 teraseconds. Usage Myr is in common use in fields such as Earth science and cosmology. Myr is also used w ...

. 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 language, 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. Description ''Trilophosaurus'' had a sh ...

'', ''T. buettneri'', and thus ''M. langstoni'' represents its

junior synonym In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The botanical and zoological codes of nomenclature treat the concept of synonymy differently. ...

.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 di ...

. 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 and distinct species of ''Malerisaurus''.

Etymology

''Malerisaurus'' was named by Sankar Chatterjee in

1980 Events January * January 4 – U.S. President Jimmy Carter proclaims a United States grain embargo against the Soviet Union, grain embargo against the USSR with the support of the European Commission. * January 6 – Global Positioning Sys ...

and the

type species In International_Code_of_Zoological_Nomenclature, 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 spe ...

is ''Malerisaurus robinsonae'' named in honour of the British Paleontologist who worked in India,

Pamela Lamplugh Robinson Pamela Lamplugh Robinson (18 December 1919 – 24 October 1994) was a British paleontologist who worked extensively on the fauna of the Triassic and Early Jurassic of Gloucestershire and later worked in India on the Mesozoic and Gondwanan fauna. Sh ...

. 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 en ...

. 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: 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 of all kno ...

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.

Classification

In their 2024 review of ''Malerisaurus'', Sengupta, Ezcurra & Bandyopadhyay analyzed its

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

placement within

. They recovered ''Malerisaurus langstoni'' as the

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

to ''

Puercosuchus ''Puercosuchus'' (translated literally as "Puerco River crocodile") is an extinct genus of archosauromorph reptile from the Late Triassic (Norian) of what is now Arizona, North America. It includes only the type species ''P. traverorum'', and was ...

'', with this clade in turn sister to ''Malerisaurus robinsonae'', together forming the clade

Malerisaurinae Azendohsauridae is a family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideal ...

. Their results are displayed in the

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

below:

References

{{Taxonbar, from=Q739142 Azendohsauridae 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