Re: Alwalkeria

["Mickey Mortimer" <Mickey_Mortimer111@msn.com>]

ekaterina A wrote-

> Thanks to Mortimer for his excellent discourse. So the
> original claim that Guaibasaurus was a basal
> saurischian does not seem to hold anymore. That honor
> seems to have gone to Hererrasaurids and Eoraptor.

Well, that original claim was made without the benefit of a cladistic
analysis.  Also, I forced Guaibasaurus to be a basal theropod in the study I
posted, so that doesn't tell us anything about its relationships.  However,
I later ran that analysis without constraints (5544 mpt's; 655 steps) and
Guaibasaurus was still a basal theropod (although as in Rauhut's original
analysis, herrerasaurids and Eoraptor were also basal theropods, each
successively more basal than Guaibasaurus).  So that does support Langer's
analysis, at least in regard to Guaibasaurus.

> Just to clarify something called "Zupaysaurus" was not
> a mispronounciation of Guaibasaurus, but something
> else shielded from public vision.

Correct.  "Zupaysaurus" lived later and differs in having a fused
astragalocalcaneum with taller ascending process at least.  It's supposedly
a tetanurine, while Guaibasaurus seems to be a basal theropod.

"Zupaysaurus"
Late Norian-Rhaetian, Late Triassic
Los Colorados Formation, Argentina
Material- (3-4 m) skull (450 mm), lower jaws, cervical vertebrae, dorsal
vertebrae, ilium, distal tibia, distal fibula, astragalus, calcaneum

Guaibasaurus Bonaparte, Ferigolo and Ribeiro 1999
= "Guaibasaurus" Bonaparte and Ferigolo 1998
G. candelariensis Bonaparte, Ferigolo and Ribeiro 1999
= "Guaibasaurus candelariai" Bonaparte and Ferigolo 1998
Late Carnian, Late Triassic
Santa Maria (=Caturitta) Formation, Brazil
Holotype- (MCN-PV 2355) five incomplete dorsal centra (22 mm), three
incomplete dorsal neural arches, five incomplete dorsal ribs, two incomplete
sacral centra (29, 19 mm), ten caudal vertebrae (51 mm), chevrons,
incomplete scapula, incomplete coracoid, incomplete ilium (~87 mm), pubes
(136 mm), incomplete ischia (131 mm), incomplete femora (~214 mm), tibiae
(~212 mm), fibulae (~207 mm), astragalus (40x22 mm), calcaneum, metatarsal I
(57 mm), phalanx I-1, ungual I, metatarsal II (85 mm), phalanx II-1, phalanx
II-2, ungual II, metatarsal III (95 mm), phalanx III-1, phalanx III-2,
phalanx III-3, ungual III, metatarsal IV (83 mm), phalanx IV-1, phalanx
IV-2, phalanx IV-3, phalanx IV-4, ungual IV, metatarsal V (41 mm)

Mickey Mortimer