''Kotasaurus'' ( ; meaning "
Kota Formation
The Kota Formation is a geological formation in India. The precise age of Kota Formation are uncertain, but it dates from the Early to Middle Jurassic, and is split into a Lower Member and Upper Member.Prasad GVR, and Manhas BK. 2007A new docodont ...
lizard") is a
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 ...
of
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 bo ...
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 Geological period, geologic period and System (stratigraphy), 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 J ...
period (
Sinemurian
In the geologic timescale, the Sinemurian is an age and stage in the Early or Lower Jurassic Epoch or Series. It spans the time between 199.3 ± 2 Ma and 190.8 ± 1.5 Ma (million years ago). The Sinemurian is preceded by the Hettangian and is ...
–
Pliensbachian
The Pliensbachian is an age of the geologic timescale and stage in the stratigraphic column. It is part of the Early or Lower Jurassic Epoch or Series and spans the time between 190.8 ± 1.5 Ma and 182.7 ± 1.5 Ma (million years ago). The Plien ...
). The only known species is ''Kotasaurus yamanpalliensis''. It was discovered in the
Kota Formation
The Kota Formation is a geological formation in India. The precise age of Kota Formation are uncertain, but it dates from the Early to Middle Jurassic, and is split into a Lower Member and Upper Member.Prasad GVR, and Manhas BK. 2007A new docodont ...
of
Telangana
Telangana (; , ) is a States and union territories of India, state in India situated on the south-central stretch of the Indian subcontinent, Indian peninsula on the high Deccan Plateau. It is the List of states and union territories of India b ...
,
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 shared its habitat with the related ''
Barapasaurus
''Barapasaurus'' ( ) is a genus of basal sauropod dinosaur from Early Jurassic rocks of India. The only species is ''B. tagorei''. ''Barapasaurus'' comes from the lower part of the Kota Formation, that dates back to the Sinemurian and Pliensb ...
''. 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
![Kotasauraus adilabad](https://upload.wikimedia.org/wikipedia/commons/5/56/Kotasauraus_adilabad.jpg)
''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
prosauropod
Sauropodomorpha ( ; from Greek, meaning "lizard-footed forms") is an extinct clade of long-necked, herbivorous, saurischian dinosaurs that includes the sauropods and their ancestral relatives. Sauropods generally grew to very large sizes, had l ...
s.
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 with ...
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 roun ...
, 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
''Barapasaurus'' ( ) is a genus of basal sauropod dinosaur from Early Jurassic rocks of India. The only species is ''B. tagorei''. ''Barapasaurus'' comes from the lower part of the Kota Formation, that dates back to the Sinemurian and Pliensb ...
'' 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 Ho ...
'' and ''
Zizhongosaurus
''Zizhongosaurus'' (meaning "Zizhong lizard") is a genus of basal herbivorous sauropod dinosaur which lived in the Early Jurassic (Toarcian) Period of China. It was a large-bodied herbivore characterized by a long neck.
Discovery and naming
Th ...
''. This grouping is now recognized to be
paraphyletic
In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...
.
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
''Jingshanosaurus'' (meaning "Jingshan lizard") is a genus of sauropodomorph dinosaurs from the early Jurassic period 201.3 million years ago that went extinct 199.3 million years ago in the Hettangian Age.
Its maximum weight was around 4.3 t ...
'', ''
Antetonitrus
''Antetonitrus'' is a genus of sauropod dinosaur found in the Early Jurassic Elliot Formation of South Africa. The only species is ''Antetonitrus ingenipes''. As one of the oldest known sauropods, it is crucial for the understanding of the origi ...
'' and ''
Chinshakiangosaurus
''Chinshakiangosaurus'' (JIN-shah-jiahng-uh-SOR-us, meaning "Chinshakiang lizard") is a genus of dinosaur and probably one of the most basal sauropods known. The only species, ''Chinshakiangosaurus chunghoensis'', is known from a fragmentary ...
''.
Discovery
All known fossils come from an area of 2,400 m
2 near the village of
Yamanpalli in
Telangana
Telangana (; , ) is a States and union territories of India, state in India situated on the south-central stretch of the Indian subcontinent, Indian peninsula on the high Deccan Plateau. It is the List of states and union territories of India b ...
, 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 Kota Formation is a geological formation in India. The precise age of Kota Formation are uncertain, but it dates from the Early to Middle Jurassic, and is split into a Lower Member and Upper Member.Prasad GVR, and Manhas BK. 2007A new docodont ...
. 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 several ...
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 (India), Musi River, in the northern part ...
.
In 2001, Yadagiri described the osteology in more detail.
References
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{{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