Maleevosaurus novojilovi Carpenter 1992
Creators: name: Carpenter, K.
Publisher: name: Zenodo
Year: 1992
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Reptilia
Dinosauria
Tyrannosauridae
Maleevosaurus
Maleevosaurus novojilovi

description: <i>Maleevosaurus</i> novojilovi <b>(Maleev) 1955</b> b Figs. 2C, 5C <i>= Gorgosaurus novojilovi Maleev 1955b</i> PIN 552-2 partial skull and skeleton. <b>Diagnosis:</b> (Cranial) Maxillary fenestra small; pro-maxillary fenestra not visible laterally; antorbital fenestra proportionally very large,and much longer than high; lacrymal horn moderately developed, not rugose; postorbital not very rugose; lower ramus of maxilla low and slender; jugal slender resulting in a very large orbit; dentary slender. (Postcranial) Cervical neural spines tall, not as reduced as in other tyrannosaurids. Acromion process of scapula virtually non-existant. Ischium has a very pronounced spur-like obturator process, and distally, the shaft curves downward. Metatarsal IV does not overlap metatarsal III at midshaft, nor does metatarsal III have much of an overlap of metatarsal II at midshaft. <b>Stratigraphic and Palaeobiogeographic Distribution:</b> Nemegt Formation,Mongolian People’s Republic. <b>Discussion:</b> That <i>Maleevosaurus</i> is a tyrannosaurid is indicated by the slightly opisthocoelous cervical centra, didactyl manus, anteroposteriorly compressed, broad cervicals,well developed anterior foot of the pubis,and broad and tall ascending process of the astragulus. Originally, the holotype of <i>Maleevosaurus</i> was one of four species of tyrannosaurid named by Maleev from Mongolia. He had named it <i>Gorgosaurus</i> novojilovi (Maleev, 1955b),but because of its small size (femur length 560 mm), Rozhdestvensky (1965) considered it a juvenile <i>Tarbosaurus</i> (<i>= Tyrannosaurus</i>) <i>bataar.</i> Gradzinski and others (1977) and Osmolska (1980) noted that the third metatarsal was considerably more slender than in <i>T. bataar</i>,and doubted that this was a juvenile character. They referred to the specimen as <i>’Gorgosaurus’</i> novojilovi. In order to determine if <i>’Gorgosaurus’ novojilovi</i> is a juvenile <i>T. bataar</i>, comparisons were made to the similarities and differences between an adult and juvenile <i>Albertosaurus libratus.</i> These were AMNH 5458,with a femur length of 1025 mm,and AMNH 5664, with a femur length of 700 mm. Comparisons were also made to a growth series of skulls of <i>T. bataar</i> (Fig. 4). In the juvenile <i>Albertosaurus</i>, the lacrymal horn is already well developed and the jugal proportionally large. In <i>T. bataar</i>, there is also no change in development of the lacrymal horn and in size of the jugal. Therefore, the moderately developed lacrymal horn and the slenderness of the jugal in ‘ <i>G</i>.’ <i>novojilovi</i> are <i>not</i> considered juvenile features. Furthermore, no change occurs in the relative size of the antorbital fenestra in <i>T. bataar</i> from juvenile to adult, indicating that the large size of the antorbital fenestra in ‘ <i>G</i>.’ <i>novojilovi</i> is also not a juvenile feature. However, <i>contrary to</i> Gradzinski and others (1977) and Osmolska (1980),it is possible that the slenderness of the third metatarsal is a juvenile character,as this metatarsal is considerably more slender in the juvenile <i>Albertosaurus</i> than in the adult. It <b>is</b> possible, however, that this is not the case in the <i>Tyrannosaurus</i> specimens available to Gradzinski and others and Osmolska,but their observations have not yet been published. It is clear from the above analysis, that except for possibly the slenderness of the third metatarsal, ‘ <i>G</i>. <i>’novojilovi</i> is not a juvenile <i>T. bataar.</i> Furthermore, <i>‘G. ’novojilovi</i> cannot be referred to the genus <i>Albertosaurus (= Gorgosaurus)</i>,nor to any other known genus of tyrannosaurid because of the large size of the antorbital fenestra, slenderness of the jugal, the very well developed obturator process, and sharply downward curved ischium. For this reason,it is best to assign <i>‘Gorgosaurus’</i> novojilovi to a new genus, <i>Maleevosaurus.</i> Although it is possible that the holotype of <i>Maleevosaurus</i> novojilovi is a juvenile, based on its small size, the neural arches are fused to their centra, and the calcaneum to the astragulus. This suggests that <i>Maleevosaurus</i> is a small tyrannosaurid.
description: Published as part of <i>Carpenter, K., 1992, Tyrannosaurids (Dinosauria) of Asia and North America, pp. 250-268 in Aspects of Nonmarine Cretaceous Geology, Beijing :China Ocean Press</i> on pages 256-257, DOI: 10.5281/zenodo.1038212
description: {"references": ["Maleev, E., 1955 a, Gigantic carnivorous dinosaurs of Mongolia: Dokladi Akademii Nauk S. S. S. R., v. 104, p. 634 - 637.", "------, 1955 b, New carnivorous dinosaurs from the Upper Cretaceous of Mongolia: Dokladi Akademii Nauk S. S. S. R., v. 104, p. 779 - 782.", "Rozhdestvensky, A., 1965, Growth changes in Asian dinosaurs and some problems of their taxonomy. paleontologicheskii Zhurnal, p. 95 - 109.", "Gradzinski, R., Kielan-Jaworowska, Z. and Maryanska, T., 1977, Upper Cretaceous Djadokhta, Barun Goyot and Nemegt formations of Mongolia, including remarks on previous subdivisions: Acta Geologica Polonica, v. 27, p. 281 - 317.", "Osmolska, H., 1980, The Late Cretaceous vertebrate assemblages of the Gobi Desert, Mongolia. Memoires de la Societe de Geologique de France, v. 139, p. 145 - 150."]}