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Journal
of Vertebrate Paleontology 23,
556-574 (2003) Jerzy Dzik Abstract.
An
accumulation of skeletons of the pre-dinosaur Silesaurus opolensis
gen. et sp. n. is described from the Keuper (Late Triassic) claystone of
Krasiejów in southern Poland. The strata are correlated with the late Carnian
Lehrberg Beds and contain a diverse assemblage of tetrapods, including the
phytosaur Paleorhinus, which in other regions of the world co-occurs
with the oldest dinosaurs. A narrow pelvis with long pubes and the extensive
development of laminae in the cervical vertebrae place S. opolensis
close to the origin of the clade Dinosauria above Pseudolagosuchus,
which agrees with its geological age. Among the advanced characters is the
beak on the dentaries, and the relatively low tooth count. The teeth have low
crowns and wear facets, which are suggestive of herbivory. The elongate, but
weak, front limbs are probably a derived feature. |