Isisaurus

  • India ( Lameta Formation)
  • Isisaurus colberti ( Jain & Bandyopadhyay, 1997)

Isisaurus is a genus of sauropod dinosaur from the group of Titanosauria. So far, a single fragmentary skull -less skeleton is known, which dates from the Late Cretaceous ( Maastrichtian ) of India. The only way is Isisaurus colberti.

Initially, this skeleton was established in 1997 as a kind of Titanosaurus - described - Titanosaurus colberti. 2003 featured Jeffrey Wilson and Paul Upchurch noted that this kind must actually be attributed to a separate genus, which they called Isisaurus.

Features

Isisaurus was a medium-sized sauropod. Like all sauropods was characterized by a barrel-shaped body and a long neck and tail of these herbivores. Isisaurus was one of the more advanced ( abgeleiteteren ) Titanosauria, which is reflected in a number of jointly derived characteristics ( synapomorphies ) shows: for example, lacked the typical for other Sauropodengruppen additional mechanical fasteners of the vertebrae, the Hyposphen - Hypantrum connections, making the spine flexible. In addition, the cubit ( ulna ) showed a distinct olecranon, a bone spur that stretched to over the condyles at the top. Furthermore, the anterior spinous processes of the vertebrae of the tail were relatively wide, while the vertebrae of the anterior and middle caudal vertebrae on the front strongly concave ( procoel ) were.

From other Titanosauria Isisaurus be distinguished by several unique features ( autapomorphies ) of the vertebrae: So the parapophyses of caudal vertebrae in the direction of the body axis ( anteroposterior ) for example, were extended. In addition, the chevron bones were shortened in the direction of body axis.

System

Phylogenetic relationships within the Titanosauria are controversial. Usually Isisaurus is classified within the Lithostrotia ( = Titanosauriae ), a group of more advanced Titanosauria. Within the Lithostrotia the group Saltasauridae is often performed, which includes very advanced Titanosauria as Saltasaurus. While Wilson ( 2002) Isisaurus holds for the sister taxon of Saltasauridae - classifies the genus ie outside the Saltasauridae - suggests Curry Rogers ( 2005), a classification within the Saltasauridae ago - as a representative of Opisthocoelicaudiinae.

Paleobiology

Researchers led by Neeta Sharma (2005) discovered fossilized dung ( coprolites ), which could come from Isisaurus. These coprolites contained various fungi that enter through the leaves of trees in the intestinal tract of these animals. Hence, the researchers that Isisaurus abweidete the crowns of trees.

Fund, Research History and naming

The site is located near Dongargaon Hill in Chandrapur district in Maharashtra in central India. The rocks of the references belong to Lameta lineup and were during the Maastrichtian, the last stage of the Upper Cretaceous deposited. The skeleton ( holotype, specimen number R335/1-65 ISI ) is associated and well preserved, unlike almost all other Indian dinosaur finds, mostly consist only of isolated bone encountered. It consists of parts of the spine, the shoulder girdle, pelvis, and a front leg without hand skeleton. Skull bones have not been found.

This skeleton was established in 1997 first described by Jain and Bandyopadhyay scientifically as Titanosaurus colberti. The skeleton overlaps with the type material of Titanosaurus, which consists only of two middle caudal vertebrae, which allows a direct comparison. Jain and Bandyopadhyay noticed important differences, such as the shape of the vertebral body and the saliency of the starting points of the chevron bones. Upchurch and Wilson ( 2003) noted, however, that these differences are too large and the common characteristics are not sufficient to continue to be regarded as a kind of Titanosaurus Titanosaurus colberti. Thus, they described the skeleton as a new genus - Isisaurus.

The name Isisaurus honors the Indian Statistical Institute ( Indian Statistical Institute, ISI), have discovered the skeleton and first described its scientists. The ending saurus is ancient Greek for lizard.

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