Diagnoza

Rauisuchid rauisuchian archosaur with the following combination of characters: thick and swollen rim delimiting the antorbital fossa on the maxilla, which continues caudally onto the jugal; absence of rostral ramus of maxilla; rugose ridge on the lateral surface of the skull roof (nasals, lacrimal, palpebral, postorbital, squamosal); large triangular palpebral ossification dorsal to the orbit (previously identified by Sulej 2005 as an enlarged prefrontal, but clearly a separate ossification); deep pit on the caudodorsal corner of the lateral surface of the squamosal; subdivided lower tempo ral fenestra. Differentiated from Teratosaurus by: a medial groove for the dental lamina that is subtle and entirely absent in some places; groove for the dental lamina (and associated tooth replacement foramina) oriented in a straight line across its entire length; first maxillary alveolus approximately equal in size to subsequent alveoli; ventralmargin of the maxilla sinuous and highly convex in outline; the caudoventral groove on medial surface of the palatal process short and poorly defined; a prominent and sharply defined caudodorsally arched ridge extending from the base of the palatal process; and a deep fossa present dorsal to the palatal process. Differentiated from Postosuchus kirkpatricki by: ventralmargin of the maxilla sinuous and highly convex in outline; first maxillary alveolus approximately equal in size to subsequent alveoli; absence of fossa on the dorsal surface of the nasal; absence of dorsoventral expansion of the rostral end of the dentary.

Porównanie

The entire preserved skeleton of the holotype specimen of Polonosuchus silesiacus, including the maxilla, was described in detail by Sulej (2005) and does not warrant redescription here. Overall, the maxilla of Polonosuchus is very similar to that of T. suevicus, but several differences are apparent (see above). Although Polonosuchus has been separated from Teratosaurus, it is possible that further discoveries of Teratosaurus material may reveal characters shared by the two genera, thus supporting a sister taxon relationship. If this is the case, then Polonosuchus could be transferred back to Teratosaurus, although this is a subjective decision if the two are sister taxa. A detailed description of all previously described material of Polonosuchus silesiacus, as well as and new cranial and postrcranial bones, is in preparation by the authors.

Autekologia

Terrestrial predator, prey: aetosaurs, silesaurs

Występowanie geograficzne

Poland

Zasięg czasowy

Late Carnian

Materiały muzealne

One incomplete articulated skeleton. 

Literatura

Brusatte, S.L., Butler, R.J., Sulej, T. and Niedźwiedzki, G. 2009. The taxonomy and anatomy of rauisuchian archosaurs from the Late Triassic of Germany and Poland. Acta Palaeontologica Polonica 54, 221–230.

Dzik, J. & Sulej, T. 2004. Pierwszy polski dinozaur. 80 pp, Śląskie Wydawnictwo ADAN, Opole.

Dzik, J. & Sulej, T. 2007. A review of the early Late Triassic Krasiejów biota from Silesia, Poland. Palaeontologia Polonica 64, 1-27.

Sulej, T. 2005 A new rauisuchian reptile (Diapsida: Archosauria) from the Late Triassic of Poland. Journal of Vertebrate Paleontology, 25, 78–86.