| Kotasaurus | |
|---|---|
 | |
| Mounted skeleton ofKotasaurus; based on the holotype | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | †Sauropodomorpha |
| Clade: | †Sauropoda |
| Genus: | †Kotasaurus Yadagiri, 1988 |
| Type species | |
| †Kotasaurus yamanpalliensis Yadagiri, 1988 | |
Kotasaurus (/ˌkoʊtəˈsɔːrəs/KOH-tə-SOR-əs; meaning "Kota Formation lizard") is agenus ofsauropoddinosaur from the EarlyJurassic period (Sinemurian–Pliensbachian[1]). The only known species isKotasaurus yamanpalliensis. It was discovered in theKota Formation ofTelangana,India and shared its habitat with the relatedBarapasaurus. 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.[2] Like some sauropods, it had a tail club that would have been used for intraspecific combat or interspecific defense.[3]
All known fossils come from an area of 2,400 m2 near the village ofYamanpalli inTelangana, approximately forty kilometres north of theBarapasaurus type locality. These finds, altogether 840 skeletal parts, were found in the late 1970s.[4] 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 theKota Formation. Thespecific name reflects the provenance from Yamanpalli. Theholotype is21/SR/PAL, an ilium.[5]
TheGeological Survey of India combined several elements into a skeletal mount and displayed it at theBirla Science Museum,Hyderabad.[2] In 2001, Yadagiri described the osteology in more detail.[2]
Kotasaurus is one of the most basal sauropods known. The general body plan was that of a typical sauropod, but in several basal (plesiomorphic) features it resemblesprosauropods.[2] Like all sauropods,Kotasaurus was an obligate quadruped,[4] while prosauropods were primitively bipedal. The body length is estimated at nine meters, with a weight of 2.5 tonnes,[6] and therefore already comparable with that of later sauropods. Thefemur 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 twistedhumerus, as well as the retention of alesser trochanter on the femur. The neural spines of the vertebrae were simply built and their centra are massive, in contrast to those of the relatedBarapasaurus, which show more hollowing, be it without pneumatisation, of the sides as a weight-saving measure.[2]
Autapomorphies (newly acquired features) include the relatively slender limb bones as well as the low and elongated preacetabular process (the forward-pointing process of theilium).[2]
Based on comparisons with sauropods that possess tail clubs (Omeisaurus andShunosaurus), a 2024 study reported the presence of fourtail clubs from among the nearly 400 bones belonging to at least 12 individuals ofKotasaurus with varying ontogenetic stage.[3]
Initially, it was not clear ifKotasaurus represented a true sauropod or a basal sauropodomorph that has to be classified outside Sauropoda.[4] Some paleontologists placed it inside a basal sauropod family called Vulcanodontidae though, together withBarapasaurus and the fragmentaryOhmdenosaurus andZizhongosaurus. This grouping is now recognized to beparaphyletic.[2]
TodayKotasaurus is recognized as one of the most basal sauropods known. The exact relationships are not entirely clear, however. A study by Bandyopadhyayet al. (2010) rendersKotasaurus to be more basal thanBarapasaurus andVulcanodon but more derived thanJingshanosaurus,Antetonitrus andChinshakiangosaurus.[1]
