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Apatosuchus, new pseudosuchian from Upper Triassic of Germany



From: Ben Creisler
bcreisler@gmail.com


A new paper that revises a "theropod" as a pseudosuchian:

Hans-Dieter Sues & Rainer R. Schoch (2013)
Reassessment of cf. Halticosaurus orbitoangulatus from the Upper
Triassic (Norian) of Germany – a pseudosuchian, not a dinosaur.
Zoological Journal of the Linnean Society 168(4): 859–872
DOI: 10.1111/zoj.12038
http://onlinelibrary.wiley.com/doi/10.1111/zoj.12038/abstract


The holotype of cf. Halticosaurus orbitoangulatus Huene, 1932,
comprises an incomplete and macerated but associated skull of an
archosaurian reptile from the middle (second) Stubensandstein (middle
Löwenstein Formation; Upper Triassic: Norian) of Baden-Württemberg,
Germany. It was originally interpreted as a theropod dinosaur but more
recently it has been suggested that this taxon has crocodylomorph
affinities. Detailed preparation of the holotype of cf. H.
orbitoangulatus has revealed much new anatomical information and
permitted reassessment of its affinities. The maxilla lacks both a
distinct antorbital fossa and a medial bony lamina bordering the
antorbital fenestra. The lateral surface of the dentary bears a
pronounced horizontal ridge. The squamosal differs from that of basal
crocodylomorphs in being L-shaped rather than arcuate in dorsal view,
lacking a dorsolateral overhang, and lacking an interlocking contact
with the paroccipital process as, for example, in the basal
crocodylomorph Saltoposuchus connectens from the same horizon and
locality. Phylogenetic analysis placed cf. H. orbitoangulatus amongst
loricatan pseudosuchians (but not amongst Crocodylomorpha) rather than
amongst theropod dinosaurs. The holotype of cf. H. orbitoangulatus
represents a previously unrecognized taxon of loricatan pseudosuchian,
which is here named Apatosuchus orbitoangulatus and set apart from
other known Norian-age non-crocodylomorph loricatans by its apparently
much smaller size.