[D] Bayosaurus [nG]
Describer
Coria, Currie and Carabajal 2006
Time
Cretaceous Late ?Turonian
Classification
Saurischia Theropoda Abelisauridae Nomen Nudem
Diet
Carnivore
Length
4 meter
Fossilsite
Lisandro Formation, Patagonia, Argentina
Info
Holotype
MCF-PVPH-237 collected in 2000 from the middle section of the Lisandro Formation at Cerro Bayo Mesa, Neuquén Province, Argentina, a partial skeleton of a small-sized abelisauroid theropod that includes the last presacral vertebrae, a partial sacrum, an incomplete right ilium, fragmants of the left ilium, pubes lacking distal ends, the proximal region of the right ischia, and other fragmentary remains. In figure 6 of Coria et al. 2006 the name Bayosaurus is mentioned.
Locality and horizon
Cerro Bayo Mesa, 30 km south of Plaza Huincul, Neuquen Province, Argentina. Lisandro Formation (Turonian?), Rio Limay Subgroup, Neuquen Group, Neuquen Basin.
Description
Probably an adult because of the fusion of the posterior dorsal neural arch to its centrum, and of the sacral vertebrae to the ilium. The almost complete, lacking only the neural spine and the distal end of the right transverse process, dorsal vertebrae was found close to the anterior end of the sacrum. The parapophysis is potioned high, almost at the level of the diapophysis. The anterior centro-parapophyseal lamina is thin and curves gently ventrally at its distal end.
The first three sacral vertebrae are partially preserved. The centra are strongly compressed laterally, as in Carnotaurus and Aucasaurus (Bonaparte et al. 1990; MCF-PVPH-236, Coria et al. 2002) The preserved parts of the neural arches are solidy fused to the ilium.The ilia had been alomost completely washed away when the specimen was found. The right ilium is the least damaged and has preserved enough information to allow to estimate its size. Only a small fragment of the preacetabular blade of the left ilium is preserved.
The supra-acetabular crest is very sharp and the acetabulum itself seems to be anteroposteriorly long and transversely narrow. On the lateral side of the preserved right ilia blade, a conspicious ridge, can be seen parallel to the dorsal edge and palced approximately 15 mm away from it. This ridge would have run all along the dorsal border of the ilium. The same feature is present in the fragmented left iliac blade.
The ilium seems to have been rather elongate and low, like those of Carnotaurus, Majungatholus and Aucasaurus. The thickened anterior, dorsal, and posterior margins of the iliac blade define a shallowly depressed lateral surface. Both pubes are almost complete and lack only the distal boots. The proximal end is firmly fused to the ilium, with no evident sutural contact. The obtutator foramen is completely serrounded by bone, as in Carnotaurus, Masiakasaurus and Aucasaurus.
Coria et al. 2006
Coria, Currie and Carabajal 2006
Time
Cretaceous Late ?Turonian
Classification
Saurischia Theropoda Abelisauridae Nomen Nudem
Diet
Carnivore
Length
4 meter
Fossilsite
Lisandro Formation, Patagonia, Argentina
Info
Holotype
MCF-PVPH-237 collected in 2000 from the middle section of the Lisandro Formation at Cerro Bayo Mesa, Neuquén Province, Argentina, a partial skeleton of a small-sized abelisauroid theropod that includes the last presacral vertebrae, a partial sacrum, an incomplete right ilium, fragmants of the left ilium, pubes lacking distal ends, the proximal region of the right ischia, and other fragmentary remains. In figure 6 of Coria et al. 2006 the name Bayosaurus is mentioned.
Locality and horizon
Cerro Bayo Mesa, 30 km south of Plaza Huincul, Neuquen Province, Argentina. Lisandro Formation (Turonian?), Rio Limay Subgroup, Neuquen Group, Neuquen Basin.
Description
Probably an adult because of the fusion of the posterior dorsal neural arch to its centrum, and of the sacral vertebrae to the ilium. The almost complete, lacking only the neural spine and the distal end of the right transverse process, dorsal vertebrae was found close to the anterior end of the sacrum. The parapophysis is potioned high, almost at the level of the diapophysis. The anterior centro-parapophyseal lamina is thin and curves gently ventrally at its distal end.
The first three sacral vertebrae are partially preserved. The centra are strongly compressed laterally, as in Carnotaurus and Aucasaurus (Bonaparte et al. 1990; MCF-PVPH-236, Coria et al. 2002) The preserved parts of the neural arches are solidy fused to the ilium.The ilia had been alomost completely washed away when the specimen was found. The right ilium is the least damaged and has preserved enough information to allow to estimate its size. Only a small fragment of the preacetabular blade of the left ilium is preserved.
The supra-acetabular crest is very sharp and the acetabulum itself seems to be anteroposteriorly long and transversely narrow. On the lateral side of the preserved right ilia blade, a conspicious ridge, can be seen parallel to the dorsal edge and palced approximately 15 mm away from it. This ridge would have run all along the dorsal border of the ilium. The same feature is present in the fragmented left iliac blade.
The ilium seems to have been rather elongate and low, like those of Carnotaurus, Majungatholus and Aucasaurus. The thickened anterior, dorsal, and posterior margins of the iliac blade define a shallowly depressed lateral surface. Both pubes are almost complete and lack only the distal boots. The proximal end is firmly fused to the ilium, with no evident sutural contact. The obtutator foramen is completely serrounded by bone, as in Carnotaurus, Masiakasaurus and Aucasaurus.
Coria et al. 2006