Describer

Dzik vide Mikoluszko, 2002

Time

Triassic Late Carnian

Classification

Not considered dinosaur

Diet

Herbivore

Fossilsite

Keuper claystone, Krasiejów, Opole, Silesia, Poland

Length

2.3 m

Info

Genus - Typespecies

PAN catalogue number not yet available: At least one nearly complete skeleton Hypodigm APK:90/90?: Remains of 20 individuals including the \\\"type\\\" skeleton.

Name of genus and speciesame of genus first appeared in the July 2002 Polish edition of National Geographic and later in late October 2002 issue of Gazeta Wyborcza. 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 Silesaurus 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.

This is a large non-dinosaurian dinosauromorph, It is restored as a long- necked quadruped, with rather gracile forelimbs. Its teeth are conical, grooved, and variably serrated. The sides of the teeth are worn, suggesting herbivory. The tip of the dentary is toothless, and the anatomy suggests it was covered by a beak. However, there is no sign of a predentary. Most of the postcranium is known.

Parts of many individuals are represented. As mentioned previously on this list, the specimen comes from the early Carnian; as recent discoveries seem to indicate the presence of Ladinian dinosaurs, this is not the oldest dinosaur as earlier announced. Furthermore, Dzik does not consider this a dinosaur at all, but instead a dinosauromorph closer to Dinosauria than was Pseudolagosuchus.

It lacks the enlarged deltopectoral crest and epiphyses on the cervical vertebra of Dinosauria. However, it has a brevis shelf, an ischium with a slender shaft, a femur with reduction of the tuberosity that laterally bounds the ligament of the femoral head, a prominent lesser trochanter, an overlap of the ascending process of the astragalus with the tibia, and a concave proximal articular surface for the reception of the distal end of the fibula on the calcaneum: all these were previously discovered to be dinosaurian synapomorphies. Its acetabulum is closed.

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