Lametasaurus (; ), is a chimeric genus of dinosaur known from the Lameta Formation of Jabalpur, India. The type species is L. indicus.
History of discovery Between October 1917 and 1919 Charles Alfred Matley excavated fossils near Jabalpur.Carrano, M.T., J.A. Wilson, P. M. Barrett, 2010, "The history of dinosaur collecting in central India since 1828", In: Moody, R.T.J., E. Buffetaut, D. Naish, and D. M. Martill (eds.), Dinosaurs and Other Extinct Saurians: A Historical Perspective. Geological Society, London, Special Publications 343: 161–173 In 1921 he reported the find in the "Carnosaur Bed" of what he considered to be two theropod dinosaurs.Matley, C.A., 1921, "On the stratigraphy, fossils and geological relationships of the Lameta beds of Jubbulpore", Records of the Geological Survey of India 53: 142–169 In 1923, he named one of these as the type species Lametasaurus indicus. The type specimen consisted of a number of dermal scutes, a sacrum of at least five sacral vertebrae ( in length), a pair of ilium (left ilium is in length with the acetabular portion, including the pubic and ischial processes, being about long and wide), a tibia ( cm long with the distal breadth being ) and teeth.Matley, C.A., 1923, "Note on an armoured dinosaur from the Lameta beds of Jubbulpore", Records of the Geological Survey of India, 55: 105-109 In 1933 Matley and Friedrich von Huene described some more remains collected by Barnum Brown, thought to have been part of a tail club;Huene, F. von, & Matley, C.A., 1933, "The Cretaceous Saurischia and Ornithischia of the central provinces of India", Palaeontologia Indica, 21: 1–74 later this was shown to be a large osteoderm.
In 1964, Alick Walker chose the scutes as the lectotype, thus removing the teeth and the bones from the type material.Walker, A., 1964, "Triassic reptiles from the Elgin area: Ornithosuchus and the origin of carnosaurs", Philosophical Transactions of the Royal Society of London B 248: 53-134
The type material has been lost, lacking a known inventory number, making it difficult to test the several hypotheses. The taxon is today commonly seen as a nomen dubium.F.E. Novas, S. Chatterjee, D.K. Rudra and P.M. Datta, 2010, "Rahiolisaurus gujaratensis, n. gen. n. sp., a new abelisaurid theropod from the Late Cretaceous of India". In: S. Badyopadhyay (ed.), New Aspects of Mesozoic Biodiversity. Lecture Notes in Earth Sciences 132, pp. 45-62
Description The weight estimate of Lametasaurus, on the basis of the robust tibia, is , similar morphology can be seen in the tibia of Pycnonemosaurus, which indicates similar weight estimates.
Classification In 1921, the specimen was described within Megalosauria, while by 1923, Matley no longer identified it as a theropod but as a member of the Stegosauria instead, which concept at the time also included the armoured dinosaurs today assigned to the Ankylosauria; at first Matley had seen it as a stegosaurian in the modern sense and even intended to name it as a species of Omosaurus. In 1935, Dhirendra Kishore Chakravarti contested the interpretation as an armoured dinosaur. He claimed that the specimen was a chimera including titanosaurid armor, crocodile teeth and theropod hindlimb material.Chakravarti, D. K., 1935, "Is Lametasaurus indicus an armored dinosaur?", American Journal of Science 30(5): 138-141
By 1964, the name Lametasaurus designated the scutes only and was generally considered to represent a member of the Nodosauridae. The pelvis and hindlimb bones have in 2003 been suggested to belong to Rajasaurus, based on shared features in the .J.A. Wilson, P.C. Sereno, S. Srivastava, D.K. Bhatt, A. Khosla and A. Sahni, 2003, "A new abelisaurid (Dinosauria, Theropoda) from the Lameta Formation (Cretaceous, Maastrichtian) of India", Contributions from the Museum of Paleontology, University of Michigan 31(1): 1-42 In 2008, Matthew Carrano e.a. discarded the possibility the scutes were ankylosaurian, stating they were probably titanosaurian, but noted that a comparison to the osteoderms of Ceratosaurus would help in determining its affinities. If in which case the species were to be found ceratosaurian, it would possibly be a senior synonym of Indosaurus and/or Rajasaurus.M.T. Carrano and S.D. Sampson, 2008, "The phylogeny of Ceratosauria (Dinosauria: Theropoda)", Journal of Systematic Palaeontology 6(2): 183-236 Most recently, it has been suggested that some of the osteoderms assigned to Lametasaurus show ankylosaurian synapomorphies, which renders Lametasaurus a chimera regardless of the affinities of the other material.
References
External links Dinosauria Translation and Pronunciation Guide Paleobiology Database