[N] 2006 Does Procompsognathus have a head?
Knoll, F. & Schoch, R. (2006) Does Procompsognathus have a head? Systematic of an enigmatic Triassic taxon. JVP 26(3) Abstracts pp.86
Procompsognathus triassicus is a taxon from the Stubensandstein of Pfaffenhofen, near Heilbronn (Baden-Württemberg, Germany), which has been the subject of persistent controversies. In order to provide clarification of the status of SMNS material ascribed to this enigmatic archosaur (SMNS 12591, 12591a, 12352, and 12352a), additional preparing as well as high-resolution X-ray CT analyses have been conducted. From a global morphological point of view, the type material, SMNS 12591, shows strong similarities with Coelophysis.
A supertree analysis suggests that Dilophosaurus, Liliensternus, Coelophysis, and Segisaurus may be successively closer sister-taxa to Procompsognathus. SMNS 12591a shows a mosaic of characters difficult to decipher in terms of phylogenetic affinities, but it is tentatively suggested that it is from an early and very plesiomorphic tetanuran based on the presence of an assumed maxillary fenestra. SMNS 12352 likely pertains to a crocodylomorph in part due to the separation between the nasal and the antorbital fossa.
SMNS 12352 has been attributed to Saltoposuchus connectens but there are some differences between SMNS 12352 and 12596 (regarding the outline of the antorbital fenestra and the depth of the maxilla at the level of the rostral part of the antorbital fenestra) that cast serious doubt on this identification. Finally, SMNS 12352a shows a definitive primitive Bauplan in being pentadactyl with no obvious differential development of the digit II. Yet, a long and powerful three-fingered hand arose in the earliest theropods whereas the hand of “thecodonts” is generally crocodile-like.
Therefore, though it cannot be definitely attested so far, the pertaining of SMNS 12352a to a crocodylomorph is substantiated. The carnivorous guild that dwelled southern Germany prior to the Tr-J boundary events was remarkably diverse and strengthens the hypothesis according to which fundamental evolution within the clade Theropoda was under way well before the Tr-J boundary events.