[D] Iguanacolossus fortis [sG] [T]
Describer
McDonald, Kirkland, DeBlieux, Madsen, Cavin, Milner & Panza 2010
Time
Cretaceous Early ?Barremian
Classification
Ornithischia Ornithopoda Iguanodontia
Diet
Herbivore
Fossilsite
Cedar Mountain Formation, Yellow Cat Member, Utah, US
Info
Abstract
Background:Basal iguanodontian dinosaurs were extremely successful animals, found in great abundance and diversity almost worldwide during the Early Cretaceous. In contrast to Europe and Asia, the North American record of Early Cretaceous basal iguanodonts has until recently been limited largely to skulls and skeletons of Tenontosaurus tilletti. Methodology/PrincipalFindings: Herein we describe two new basal iguanodonts from the Yellow Cat Member of the Cedar Mountain Formation of eastern Utah, each known from a partial skull and skeleton. Iguanacolossus fortis gen. et sp. nov. and Hippodraco scutodens gen. et sp. nov. are each diagnosed by a single autapomorphy and a unique combination of characters. Conclusions/Significance: Iguanacolossus and Hippodraco add greatly to our knowledge of North American basal iguanodonts and prompt a new comprehensive phylogenetic analysis of basal iguanodont relationships. This analysis indicates that North American Early Cretaceous basal iguanodonts are more basal than their contemporaries in Europe and Asia.
Holotype
UMNH VP 20205, the associated partial skeleton of a single individual.
Diagnosis
Basal styracosternan diagnosed by a single autapomorphy: contact surface for supraoccipital on caudomedial process of squamosal is sinuous in caudal view. Also distinguished by a unique combination of characters: postorbital process of the squamosal mediolaterally compressed and blade-like; axial neural spine blade-like and semi-circular in profile; cranial extremity of preacetabular process of ilium modified into orizontal boot; dorsal margin of ilium straight; cranial pubic process with concave dorsal margin but little expansion of its cranial end (dorsal and ventral margins both curve dorsally); pubis tapers to a blunt point.
Locality and Horizon
Don’s Ridge (discovered by DDD in 2005), UMNH VP locality 1206, near Green River, Grand County, Utah; exact locality information is on file at the Utah Geological Survey and Utah Museum of Natural History. Collected in the lower portion of the Yellow Cat Member of the Cedar Mountain Formation (? lower Barremian, Lower Cretaceous).
Etymology
Iguanacolossus, a combination of Iguana and the Latin colossus, in reference to the herbivorous lizards of the genus Iguana, the teeth of which have been historically compared to those of basal iguanodonts, and to the large size of the holotype skeleton; fortis from the Latin (mighty). The gender of the genus is masculine. The intended meaning of the binomen is ‘‘mighty iguana colossus’’.
McDonald, Kirkland, DeBlieux, Madsen, Cavin, Milner & Panza 2010
Time
Cretaceous Early ?Barremian
Classification
Ornithischia Ornithopoda Iguanodontia
Diet
Herbivore
Fossilsite
Cedar Mountain Formation, Yellow Cat Member, Utah, US
Info
Abstract
Background:Basal iguanodontian dinosaurs were extremely successful animals, found in great abundance and diversity almost worldwide during the Early Cretaceous. In contrast to Europe and Asia, the North American record of Early Cretaceous basal iguanodonts has until recently been limited largely to skulls and skeletons of Tenontosaurus tilletti. Methodology/PrincipalFindings: Herein we describe two new basal iguanodonts from the Yellow Cat Member of the Cedar Mountain Formation of eastern Utah, each known from a partial skull and skeleton. Iguanacolossus fortis gen. et sp. nov. and Hippodraco scutodens gen. et sp. nov. are each diagnosed by a single autapomorphy and a unique combination of characters. Conclusions/Significance: Iguanacolossus and Hippodraco add greatly to our knowledge of North American basal iguanodonts and prompt a new comprehensive phylogenetic analysis of basal iguanodont relationships. This analysis indicates that North American Early Cretaceous basal iguanodonts are more basal than their contemporaries in Europe and Asia.
Holotype
UMNH VP 20205, the associated partial skeleton of a single individual.
Diagnosis
Basal styracosternan diagnosed by a single autapomorphy: contact surface for supraoccipital on caudomedial process of squamosal is sinuous in caudal view. Also distinguished by a unique combination of characters: postorbital process of the squamosal mediolaterally compressed and blade-like; axial neural spine blade-like and semi-circular in profile; cranial extremity of preacetabular process of ilium modified into orizontal boot; dorsal margin of ilium straight; cranial pubic process with concave dorsal margin but little expansion of its cranial end (dorsal and ventral margins both curve dorsally); pubis tapers to a blunt point.
Locality and Horizon
Don’s Ridge (discovered by DDD in 2005), UMNH VP locality 1206, near Green River, Grand County, Utah; exact locality information is on file at the Utah Geological Survey and Utah Museum of Natural History. Collected in the lower portion of the Yellow Cat Member of the Cedar Mountain Formation (? lower Barremian, Lower Cretaceous).
Etymology
Iguanacolossus, a combination of Iguana and the Latin colossus, in reference to the herbivorous lizards of the genus Iguana, the teeth of which have been historically compared to those of basal iguanodonts, and to the large size of the holotype skeleton; fortis from the Latin (mighty). The gender of the genus is masculine. The intended meaning of the binomen is ‘‘mighty iguana colossus’’.