Gracilisuchus

Desojo, Julia B., Ezcurra, Martin D. & Schultz, Cesar L., 2011, An unusual new archosauriform from the Middle-Late Triassic of southern Brazil and the monophyly of Doswelliidae, Zoological Journal of the Linnean Society 161 (4), pp. 839-871 : 868-869

GRACILISUCHUS

In the following review of the character states of the data matrix of Dilkes & Sues (2009), we only used the holotype of Gracilisuchus (PULR 08) and its referred specimen PVL 4597. The specimen MCZ 4116 was not included in the current review because we are not confident of its assignment to Gracilisuchus . In this regard, the specimen MCZ 4116 differs from the holotype of Gracilisuchus in the presence of an obtuse angle between the anterior and posterior processes of the postorbital, strong anterior development of the iliac preacetabular process, and ilium with downturned iliac blade.

Character 10: in the holotype of Gracilisuchus the presence of a postfrontal cannot be confidently determined ( PULR 08 ). Thus the character state has been rescored as (?) instead of (0) in this taxon .

Character 14: in Gracilisuchus (PVL 4597) the anterior process of the jugal reaches the posteroventral margin of the internal antorbital fenestra. In this regard, this character state has been modified to (0) instead of (1).

Character 16: the dorsal margin of the antorbital fossa is extended along the ascending process of the maxilla and the anterior process of the lacrimal; thus it does not reach the frontal or postorbital (PVL 4612). Accordingly, the character state has been changed to (0) instead of (1).

Character 36: in the available specimens of Gracilisuchus (PULR 08, PVL 4597) this character cannot be confidently assessed. Thus, this character state was modified to (?) instead of (1).

Character 41: in Gracilisuchus the pterygoids contact each at their posterior end, but they diverge anteriorly at a low angle, resulting in an interpterygoid median opening (PULR 08). As a result, the character state has been changed to (1) instead of (0) in Gracilisuchus .

Character 47: in the holotype specimen of Gracilisuchus the centra of the mid-cervical vertebrae are longer than that of the mid-dorsals ( PULR 08 ; Romer, 1972a). In this regard, this character state has been changed to (1) instead of (0) .

Character 52: in the holotype of Gracilisuchus the entire dorsal series with their respective ribs is available. In this specimen the dorsal ribs are dichocephalous ( PULR 08 ), resulting in a rescoring of the character state as (1) instead of (?) .

Character 57: the available pectoral girdle materials of Gracilisuchus belong to the holotype ( PULR 08 ), and in this specimen this condition cannot be confidently assessed. Accordingly, we have modified this character state to (?) instead of (1) .

Character 62: in PVL 4597 the pubic tubercle is poorly developed on the lateral surface of the proximal end of the bone. As a result, this character state has been rescored as (1) instead of (?) in Gracilisuchus .

Character 64: in a recent review of the hindlimb anatomy of Gracilisuchus , the presence of a poorly developed fourth trochanter is described (Lecuona, 2007; A. Lecuona & J.B. Desojo, unpubl. data; PVL 4597) (contra Romer, 1972a). Accordingly, the character state has been changed to (0) instead of (1).

Character 82: Gracilisuchus exhibits a nonreduced first phalanx of digit V (Lecuona, 2007; PVL 4597). In this regard, this character has been rescored as (0) instead of (1).

Character 83: the available phalanx V-1 of Gracilisuchus is a nonreduced element suggesting the presence of more distal phalanges (PVL 4597). In this regard, the total length of the pedal digit V cannot be determined. Thus, the character state (?) has been introduced instead of (1).