''Laevisuchus'' (, "light crocodile") is a

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 ...

theropod Theropoda (; from ancient Greek , (''therion'') "wild beast"; , (''pous, podos'') "foot"">wiktionary:ποδός"> (''pous, podos'') "foot" is one of the three major groups (clades) of dinosaurs, alongside Ornithischia and Sauropodom ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

. Its remains were discovered by

Charles Alfred Matley Charles Alfred Matley (1866–1947) was a British paleontologist and geologist in India, the British West Indies and Wales. Matley was educated at Birmingham University, and earned a doctorate in geology (D.Sc.) from the University of London in J ...

near

Jabalpur Jabalpur, formerly Jubbulpore, is a city situated on the banks of Narmada River in the state of Madhya Pradesh, India. It is the 3rd-largest urban agglomeration of the state and the 38th-largest of the country. Jabalpur is the administrative h ...

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

"Carnosaur Bed" deposits in the

Lameta Formation The Lameta Formation, also known as the Infratrappean Beds (not to be confused with the contemporaneous Intertrappean Beds), is a sedimentary geological formation found in Madhya Pradesh, Gujarat, Maharashtra, Telangana, and Andhra Pradesh, Indi ...

Madhya Pradesh Madhya Pradesh (; ; ) is a state in central India. Its capital is Bhopal and the largest city is Indore, Indore. Other major cities includes Gwalior, Jabalpur, and Sagar, Madhya Pradesh, Sagar. Madhya Pradesh is the List of states and union te ...

, central

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 were named and described by

paleontologist Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geolo ...

Friedrich von Huene Baron Friedrich Richard von Hoyningen-Huene (22 March 1875 – 4 April 1969) was a German nobleman paleontologist who described a large number of dinosaurs, more than anyone else in 20th-century Europe. He studied a range of Permo-Carbonife ...

and Matley in 1933. 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 ''Laevisuchus indicus''. The generic name is derived from

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''laevis'', "light" and the Greek name for the ancient Egyptian crocodile god, '' Soukhos''. 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 ...

means "Indian" in

. It is known only from three cervical

vertebrae Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal ...

(GSI K20/613, GSI K20/614, and GSI K27/696) and a dorsal vertebra (GSI K27/588). A

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 ...

was not assigned by Huene and Matley, and a

lectotype In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to anchor or centralizes ...

has never been chosen from the

syntype In biological nomenclature, a syntype is any one of two or more biological types that is listed in a description of a taxon where no holotype was designated. Precise definitions of this and related terms for types have been established as part o ...

s. All remains except GSI K27/696 were lost, though GSI K20/613 was rediscovered in 2012. A 2024 revision of the small-bodied theropods from India classified ''

Jubbulpuria tenuis ''Jubbulpuria'' (" Jubbulpore one") is the name given to a dubious genus of small dinosaur from the Late Cretaceous Lameta Formation of India. Discovery and naming The genus was in 1932 named by Friedrich von Huene.Huene, F. von, (1932), '' ...

'' as a junior synonym of ''Laevisuchus'', and suggested that other taxa (''

Compsosuchus ''Compsosuchus'' (meaning "elegant crocodile") is a dubious genus of abelisauroid dinosaur from the Late Cretaceous Lameta Formation of India. Discovery and naming ''Compsosuchus'' was described in 1933 by von Huene and Matley based on remai ...

solus'' and ''

Ornithomimoides ''Ornithomimoides'' ("bird mimic-like") is a dubious genus of theropod dinosaur, from the Late Cretaceous (Maastrichtian stage, sometime between 70 and 66 mya) Lameta Formation of India. Two species have been identified, the type species ''O. m ...

''? ''barasimlensis'') are likely indeterminate abelisaurs.

Description

''Laevisuchus'' was a small bipedal carnivore about the same size as ''

Masiakasaurus ''Masiakasaurus'' is a genus of small predatory noasaurid theropod dinosaurs from the Late Cretaceous of Madagascar. In Malagasy, ''masiaka'' means "vicious"; thus, the genus name means "vicious lizard". The type species, ''Masiakasaurus knopf ...

'', which is estimated to be around in length. It was described on the basis of cervical (GSI K20/614, GSI K20/613, GSI K27/696) and dorsal vertebrae (GSI K27/588), being distinguished by blunt pre- and postzygapophyses, shorter proportions, and a central neural spine position in dorsal view, unlike the relative ''

''. Its broader neural arch and deeper incisions in spinopostzygapophyseal laminae differentiate it from ''

Noasaurus ''Noasaurus'' ("Northwestern Argentina lizard") is a genus of Ceratosauria, ceratosaurian theropod dinosaur from the Maastrichtian (Late Cretaceous) of Argentina. The Type species, type and only species is ''N. leali''. The fragmentary holotype s ...

''. GSI K27/696 features a neural arch significantly broader and longer than the centrum, creating a top-heavy look. Pneumatopores on its sides and uneven joint surfaces accentuate this look, while pronounced parapophyses suggest ventral expansion. The referred caudal vertebrae GSI K20/612 and GSI K27/614 (''Jubbulpuria'') are similar in size and shape, potentially from the same ''Laevisuchus'' specimen. The former lacks features such as the transverse processes and neural spine, and the latter is slightly stouter, indicating a more proximal tail position. A partial right dentary RTMNU/DG/VERT/1/55P/2020, shares features with the noasaurid ''Masiakasaurus'', and, while it wasn't formally referred to as ''Laevisuchus'', it was suggested to come from it or a related form. Jubbulpuria

Classification

''Laevisuchus'' was originally classified by Huene as a " coelurid" due to the similarity of its vertebrae with those of the Coelurosaur ''

Aristosuchus ''Aristosuchus'' is a genus of small coelurosaurian dinosaur whose name was derived from the Greek ἄριστος (meaning bravest, best, noblest) and ''σουχος'' (the Ancient Greek corruption of the name of the Egyptian crocodile-headed go ...

''. However, an analysis in 2004 has shown it to be an

abelisaur Ceratosaurs are members of the clade Ceratosauria, a group of dinosaurs defined as all theropods sharing a more recent common ancestor with '' Ceratosaurus'' than with birds. The oldest known ceratosaur, '' Saltriovenator'', dates to the earlie ...

oid because of its long epipophyses, a pair of foramina on the centrum, and low and triangular neural spines. The vertebrae specifically resemble those of noasaurids like ''

'' and ''

'' due to having more anteriorly placed neural spines and posteriorly reduced

epipophyses Epipophyses are bony projections of the cervical vertebrae found in archosauromorphs, particularly dinosaurs (including some basal birds). These paired processes sit above the postzygapophyses on the rear of the vertebral neural arch. Their m ...

.Tykoski, R.S. & Rowe, T. (2004). "Ceratosauria". In: Weishampel, D.B., Dodson, P., & Osmolska, H. (Eds.) ''The Dinosauria'' (2nd edition). Berkeley: University of California Press. Pp. 47–70 The ''Jubbulpuria'' material was originally classified by Huene as another " coelurid" similar to but smaller than ''

Coeluroides ''Coeluroides '' ("hollow form") is an extinct genus of theropod dinosaur that lived during the Late Cretaceous Period in what is now India. It is based solely on the holotype caudal vertebrae GSI K27/562, K27/574 and K27/595, discovered in a lay ...

'', another poorly known theropod from the Lameta Formation. In 2024, ''Laevisuchus'' was recovered as a member of the

Noasauridae Noasauridae is an extinct family of theropod dinosaurs belonging to the group Ceratosauria. They were closely related to the short-armed Abelisauridae, abelisaurids, although most noasaurids had much more traditional body types generally simila ...

, in an unresolved position outside the clade that includes ''

'' and ''

''. ''Jubbulpuria'' was also considered a possible

synonym A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

of ''Laevisuchus''. Later in 2024, Hendrickx ''et al''. recovered ''Noasaurus'' in a

polytomy An internal node of a phylogenetic tree is described as a polytomy or multifurcation if (i) it is in a rooted tree and is linked to three or more child subtrees or (ii) it is in an unrooted tree and is attached to four or more branches. A tree ...

with ''Laevisuchus'', ''Masiakasaurus'', ''Velocisaurus'', and ''

Vespersaurus ''Vespersaurus'' (meaning "western lizard") is a genus of noasaurid theropod dinosaur from the Cretaceous Rio Paraná Formation in the Paraná Basin, Brazil. The type and only species is ''V. paranaensis'', which would have lived in the giant pre ...

'', likely representing a radiation of small-bodied noasaurids that occurred during the Late Cretaceous.

References

{{Taxonbar, from=Q1850654 Noasauridae Dinosaur genera Maastrichtian dinosaurs Fossil taxa described in 1933 Taxa named by Friedrich von Huene Taxa named by Charles Alfred Matley Dinosaurs of India

Description

Classification

See also

References