Syntarsus Raath, 1969

Rauhut, Oliver W. M., 2003, The interrelationships and evolution of basal theropod dinosaurs, Special papers in palaeontology 69, pp. 1-213 : 19

Syntarsus Raath, 1969

Included taxa. Syntarsus kayentakatae Rowe, 1989 ; Syntarsus rhodesiensis Raath, 1969 .

Temporal range.?Hettangian-Pliensbachian.

Occurrence. Kayenta Formation, Arizona, USA; Forest Sandstone, Matabeleland, Zimbabwe; Upper Elliot Formation, Cape Province, South Africa.

Diagnosis. Presence of a postnasal fenestra between nasal, prefrontal, and frontal.

Remarks. Syntarsus ( Text-fig. 5b ) is among the best-represented taxa of theropod dinosaur. Both species are known from more than 15 specimens (Rowe and Gauthier 1990), but, unfortunately, only the holotypes of the species have been described in detail so far ( Raath 1969; Rowe 1989). Since its original description, Syntarsus has been regarded as a close relative of the Triassic North American theropod Coelophysis (e.g. Raath 1969; Colbert 1989), and has sometimes even been synonymized with the latter genus (Paul 1988 «, 1993). However, according to Colbert (1989), Coelophysis lacks the postnasal fenestra, a character that is diagnostic for Syntarsus . Given this morphological disparity, the stratigraphical difference, and the fact that Coelophysis must be regarded as a metataxon (Padian 1986), it seems best to retain them as different genera.

Figures

text-fig. 5. Skull reconstructions of representatives of Jurassic OTUs in left lateral view, a, Dilophosaurus wetherilli, Early Jurassic (Sinemurian-Pliensbachian), Kayenta Formation, Arizona, USA; based on UCMP V 4214 and V 6468. B, Syntarsus rhodesiensis, Early Jurassic (Hettangian-Sinemurian), Forest Sandstone, Zimbabwe; composite reconstruction based on many isolated skull elements from the National Museum of Natural History in Harare (see Appendix), c, Magnosaurus oxoniensis, Middle Jurassic (Callovian), Oxford Clay, England; based on OUM J 13558, unpreserved elements shaded. D, Monolophosaurus jiangi, Middle Jurassic, Wucaiwan Formation, China; redrawn from Zhao and Currie (1993b). E, Allosaurus fragilis, Late Jurassic (Kimmeridgian-Tithonian), Morrison Formation, USA; based on MOR 693. f, basal bird Archaeopteryx sp., Late Jurassic (Tithonian), lithographic limestones of Solnhofen, Germany; based on Wellnhofer (1974), Elzanowski and Wellnhofer (1996), and the Berlin, Eichstätt, and Munich specimens. G, Ceratosaurus sp., Late Jurassic (Kimmeridgian-Tithonian), Morrison Formation, USA; based on USNM 4735 and UMNH VP 5278. H, Ornitholestes hermanni, Late Jurassic (Kimmeridgian-Tithonian), Morrison Formation, USA, based on AMNH 619. Abbreviations as in Text-figure 4, and: If, lacrimal fenestra; mf, maxillary fenestra; nf, nasal foramen; pmf, promaxillary fenestra. Scale bars represent 10 mm (b, f, h), 50 mm (c) and 100 mm (a, d, e, g).