''Kotasaurus'' ( ; meaning " Kota Formation lizard") is a

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 ...

sauropod Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', ' lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their ...

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

from the Early

Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...

period ( Sinemurian–

Pliensbachian The Pliensbachian is an age (geology), age of the geologic timescale and stage (stratigraphy), stage in the stratigraphic column. It is part of the Early Jurassic, Early or Lower Jurassic epoch (geology), Epoch or series (stratigraphy), Series an ...

). The only known species is ''Kotasaurus yamanpalliensis''. It was discovered in the Kota Formation of

Telangana Telangana (; , ) is a state in India situated on the south-central stretch of the Indian peninsula on the high Deccan Plateau. It is the eleventh-largest state and the twelfth-most populated state in India with a geographical area of and 35 ...

India India, officially the Republic of India (Hindi: ), 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 and dependencies by population, second-most populous ...

and shared its habitat with the related '' Barapasaurus''. So far the remains of at least 12 individuals are known. The greater part of the skeleton is known, but the skull is missing, with the exception of two teeth. Like all sauropods, it was a large, quadrupedal herbivore with long neck and tail.

Description

''Kotasaurus'' is one of the most basal sauropods known. The general body plan was that of a typical sauropod, but in several basal (

plesiomorphic In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades. Plesiomorphy, symplesiomorphy, apomorphy, and ...

) features it resembles prosauropods. Like all sauropods, ''Kotasaurus'' was an obligate quadruped, while prosauropods were primitively bipedal. The body length is estimated at nine meters, with a weight of 2.5 tonnes, and therefore already comparable with that of later sauropods. The

femur The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates ...

was straight and oval in cross section, which means that the limbs were already columnar. The teeth were spoon-shaped, like those of later sauropods. Basal features, on the other hand, include the relatively short and slightly twisted

humerus The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a r ...

, as well as the retention of a

lesser trochanter The lesser trochanter is a conical posteromedial bony projection of the femoral shaft. it serves as the principal insertion site of the iliopsoas muscle. Structure The lesser trochanter is a conical posteromedial projection of the shaft of the fe ...

on the femur. The neural spines of the vertebrae were simply built and their centra are massive, in contrast to those of the related ''Barapasaurus'', which show more hollowing, be it without pneumatisation, of the sides as a weight-saving measure.

Autapomorphies In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to t ...

(newly acquired features) include the relatively slender limb bones as well as the low and elongated preacetabular process (the forward-pointing process of the ilium).

Classification

Initially, it was not clear if ''Kotasaurus'' represented a true sauropod or a basal sauropodomorph that has to be classified outside Sauropoda. Some paleontologists placed it inside a basal sauropod family called Vulcanodontidae though, together with '' Barapasaurus'' and the fragmentary ''

Ohmdenosaurus ''Ohmdenosaurus'' ("Ohmden lizard") is a genus of sauropod dinosaur that lived during the Early Jurassic epoch in what is now Germany. The only specimen – a tibia (shinbone) and ankle – was discovered in rocks of the Posidonia Shale near H ...

'' and '' Zizhongosaurus''. This grouping is now recognized to be

paraphyletic In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and most of its descendants, excluding a few monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In ...

. Today ''Kotasaurus'' is recognized as one of the most basal sauropods known. The exact relationships are not entirely clear, however. A recent study by Bandyopadhyay ''et al.'' (2010) renders ''Kotasaurus'' to be more basal than ''Barapasaurus'' and ''Vulcanodon'' but more derived than '' Jingshanosaurus'', '' Antetonitrus'' and '' Chinshakiangosaurus''.

Discovery

All known fossils come from an area of 2,400 m² near the village of Yamanpalli in

, approximately forty kilometres north of the ''Barapasaurus'' type locality. These finds, altogether 840 skeletal parts, were found in the late 1970s. In 1988 they were named and described by P.M. Yadagiri as a new genus and species of sauropod, ''Kotasaurus yamanpalliensis''. The generic name refers to the Kota Formation. The specific name reflects the provenance from Yamanpalli. 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 seve ...

is 21/SR/PAL, an ilium. The

Geological Survey of India The Geological Survey of India (GSI) is a scientific agency of India. It was founded in 1851, as a Government of India organization under the Ministry of Mines, one of the oldest of such organisations in the world and the second oldest survey ...

combined several elements into a skeletal mount and displayed it at the

Birla Science Museum B. M. Birla Science Museum is an Indian science museum located in Hyderabad, India. Constructed by civil engineer P. A. Singaravelu, it comprises a planetarium, museum, science centre, art gallery as well as a dinosaurium. The museum itself was ...

Hyderabad Hyderabad ( ; , ) is the capital and largest city of the Indian state of Telangana and the ''de jure'' capital of Andhra Pradesh. It occupies on the Deccan Plateau along the banks of the Musi River, in the northern part of Southern Indi ...

. In 2001, Yadagiri described the osteology in more detail.

References

{{Taxonbar, from=Q135306 Sauropods Dinosaurs of India and Madagascar Early Jurassic dinosaurs of Asia Pliensbachian life Sinemurian life Fossils of India Fossil taxa described in 1988