[D] Arctosaurus osborni [ncG]
Describer
Adams, 1875
Classification
Not considered dinosaur
Fossilsite
Heiberg Formation, Bathurst Group, Cameron Island, Nunavut, NW Territories, Canada
Info
Genus - Typespecies
Holotype: NMI 62 1971, cervical vertebra.
The species Arctosaurus osborni is based on a vertebra that was once considered to be theropodan (once supposedly the first dino ever described from Canada) but is presently thought to be either chelonian or trilophosaurid.
Taxonomic placement by Nesbitt, S.J., Irmis, R.B. and Parker, W.G. (2007): Archosauriformes indet. of a brevis fossa would represent the retention of the plesiomorphic state in some basal saurischians.
Originally described as a reptile of unknown affinities (Adams 1875). Subsequently it was considered to represent an anchisaurid sauropodomorph (Lydekker 1889), a chelonian (Huene 1906; White 1973), a melanorosaurid sauropodomorph (Huene 1956), or a thecodontosaurid (Romer 1966). Galton & Cluver (1976) demonstrated that Arctosaurus was not a sauropodomorph and provisionally referred it to the Theropoda following Steel (1970).
Remarks by Nesbitt, S.J., Irmis, R.B. and Parker, W.G. (2007): Whereas the overall morphology of the vertebrae along with the presence of epipophyses suggests placement in the Theropoda, these characters have a much wider distribution among archosaurs. Therefore, Arctosaurus can only be considered Archosauriformes indet. at this time.
Adams, 1875
Classification
Not considered dinosaur
Fossilsite
Heiberg Formation, Bathurst Group, Cameron Island, Nunavut, NW Territories, Canada
Info
Genus - Typespecies
Holotype: NMI 62 1971, cervical vertebra.
The species Arctosaurus osborni is based on a vertebra that was once considered to be theropodan (once supposedly the first dino ever described from Canada) but is presently thought to be either chelonian or trilophosaurid.
Taxonomic placement by Nesbitt, S.J., Irmis, R.B. and Parker, W.G. (2007): Archosauriformes indet. of a brevis fossa would represent the retention of the plesiomorphic state in some basal saurischians.
Originally described as a reptile of unknown affinities (Adams 1875). Subsequently it was considered to represent an anchisaurid sauropodomorph (Lydekker 1889), a chelonian (Huene 1906; White 1973), a melanorosaurid sauropodomorph (Huene 1956), or a thecodontosaurid (Romer 1966). Galton & Cluver (1976) demonstrated that Arctosaurus was not a sauropodomorph and provisionally referred it to the Theropoda following Steel (1970).
Remarks by Nesbitt, S.J., Irmis, R.B. and Parker, W.G. (2007): Whereas the overall morphology of the vertebrae along with the presence of epipophyses suggests placement in the Theropoda, these characters have a much wider distribution among archosaurs. Therefore, Arctosaurus can only be considered Archosauriformes indet. at this time.