INVESTIGADORES
MARSICANO Claudia Alicia
artículos
Título:
Dinosaur origins: evidence from the footprints record
Autor/es:
MARSICANO, CLAUDIA; DOMNANOVICH, NADIA; MANCUSO, ADRIANA
Revista:
Historical Biology
Editorial:
Taylor & Francis
Referencias:
Lugar: London; Año: 2007 vol. 19 p. 83 - 91
ISSN:
0891-2963
Resumen:
Triassic tracks and trackways assigned to dinosaur trackmakers or closest relatives have been mentioned from several Middle
to the latest Triassic successions from both northern and southern Pangea. At present, the earliest gondwanan records are
those from the Middle Triassic Los Rastros Formation in west-central Argentina. A reanalysis of Los Rastros ichnites at the
Ischichuca area, including new material, has revealed the presence of a more diverse ichnofauna than previously suspected.
The ichnocoenosis includes several tracks and trackways of bipeds with functionally tridactyl digitigrade pes, well developed
claws, and a parasagittal posture of the hindlimbs. Previously, some large tridactyl footprints from the Ischichuca area were
allied to theropod dinosaurs, although no synapomophies are preserved in the three-toed footprints that might discriminate
among theropods, basal saurischians and basal ornithischian groups as their possible trackmakers. If the Ischichuca
trackmakers are referred to a dinosaur taxon and/or to a close dinosaur sister-taxon, their presence in the Los Rastros levels
suggests that derived dinosauriforms (including dinosaurs) had diverged and acquired their characteristic functionally
tridactyl pes by at least the Middle Triassic, something that the body-fossil record has failed to document to date.