Lametasaurus

  • India ( Lameta Formation)
  • Lametasaurus indicus

Lametasaurus is a possible dubious genus of dinosaur from the Upper Cretaceous ( Maastrichtian ) of India. It was described in 1923 by Charles Matley based on pelvic bone, a shin bone and skin plates ( osteoderms ) that originate from the Lameta formation of Bara Simla, a hill in the central Indian Madhya Pradesh. This Fund is now lost. Initially, the genus has been described as a representative of the Stegosauridae; However, later it turned out that the Fund from the remains of various species composed ( chimera ): So he closes the bones of theropod and osteoderms with one, probably dating from sauropods and crocodiles. The pelvic bone and tibia of Abelisauridae are now attributed to a group of theropods within the Ceratosauria.

The name Lametasaurus ( " Lameta "; sauros gr - " lizard" ) has the Lameta Formation, the rock unit from which date the fossils.

History of Research

The fossils were recovered in 1917 by Charles Matley from the so-called " Carnosaurier - beds " of Bara Simla. In a preliminary examination of the material Matley noted that some scale-like, spine- and plate-like osteoderms were attributed to a theropod from the group of Carnosauria, and referred to Ceratosaurus, are known also from the osteoderms. After the remaining fossils were prepared, however, recognized Matley bones of a Stegosauriden ( an armored dinosaur ) - a sacrum ( sacrum ), both iliac bones ( Ilia ) and a left shin (tibia). He concluded that the osteoderms this Stegosauriden had been covered. In 1923 he described on the basis of these findings, the new genus Lametasaurus and held it for a close relative of the Stegosauriden Omosaurus - so that these fossils were considered to be the first definitive detection of an armored dinosaur from Asia. Later Matley and Friedrich von Huene suspected that the neck of this genus was armored with osteoderms arranged in rings. A later discovered by Barnum Brown big Osteoderm they interpreted Meanwhile, as the tail lobe, similar to that which is known of Ankylosaurus. Because of these osteoderms these researchers Lametasaurus now classified as a representative of the Nodosauridae.

1935 comes Dhirendra Kishore Chakravarti to conclude that the pelvic bone and tibia can be assigned neither a relative of Omosaurus, nor a Nodosauriden, but come from a megalosauriden theropods. Thus, these researchers clear differences Stegosaurus, Omosaurus and Nodosaurus; For example, the sacrum relative was significantly flattened longer and not vertically. The osteoderms could not be definitely assigned to an armored dinosaurs; some would possibly also come from theropods. Some large bone plates wrote these researchers, however, to crocodiles. The alleged tail lobe is now classified as a Osteoderm Titanosauriers.

Features

In comparison with other Ceratosauria tibia was relatively short and resilient, similar to Majungasaurus, but unlike Aucasaurus and Xenotarsosaurus. The iliac possibly had a particularly wide brevis shelf, serving as a point of attachment for the tail bone muscle extension.

Validity

The validity of the genus Lametasaurus is considered doubtful, usually it is classified as a noun dubium ( nude name). Lametasaurus is only the first of more than half a dozen genera of Abelisauridae that have been described from the Lameta lineup. Since the bones were rarely found in the context, but usually insulated, and since a large part of these fossils has been lost today, these genera can not make sense distinguish from each other in the current situation. So was the bone material, which has been described as Lametasaurus, Coeluroides, Dryptosauroides, Indosuchus, Indosaurus, Ornithomimoides mobilis and Rajasaurus, probably only one or two different genera.

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