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Aetosaurs made Brachychirotherium footprints



From: Ben Creisler
bscreisler@yahoo.com

A another new paper:
 
Spencer G. Lucas & Andrew B. Heckert (2011)
Late Triassic Aetosaurs as the Trackmaker of the Tetrapod Footprint Ichnotaxon 
Brachychirotherium. 
Ichnos 8(4): 197-208
DOI:10.1080/10420940.2011.632456
http://www.tandfonline.com/doi/abs/10.1080/10420940.2011.632456

Abstract
Brachychirotherium is the common ichnogenus of Late Triassic chirothere 
footprints well known from western Europe, North America, Argentina and South 
Africa. Although it has long been agreed by most workers that the trackmaker of 
Brachychirotherium was a derived crurotarsan archosaur, the trackmaker has been 
identified as either a rauisuchian or an aetosaur, and some workers attribute 
it to a primitive crocodylomorph (sphenosuchian). New knowledge of the 
osteology of the manus and pes of a large aetosaur, Typothorax coccinarum, 
indicates a close correspondence between the manus and pes structure of 
aetosaurs and the morphology of Brachychirotherium. Furthermore, functional 
analysis of complete skeletons indicates aetosaurs plausibly placed their feet 
in the narrow gauge, nearly the overstepped walk characteristic of 
Brachychirotherium. Brachychirotherium and aetosaurs have matched 
distributions, that is, they were Pangea-wide during the Late Triassic.
 The manus and pes morphology of rauisuchians and early crocodylomorphs 
(sphenosuchians) deviate from Brachychirotherium footprint morphology in key 
features, thus excluding their identification as trackmakers. Aetosaurs made 
Brachychirotherium footprints.