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Showing posts from May, 2008

Pelvic muscles for aquatic locomotion in crocs

It is widely known that crocodilians use a unique form of diaphragmatic breathing (Gans and Clark 1976; Farmer and Carrier 2000). Diaphragmatic breathing in crocodilians employs a hepatic piston or the movement of the liver driven by the diaphragmatic muscle. The diaphragmatic muscle attaches to the pelvis and to the liver. Contraction of the diaphragmatic muscle pulls the liver caudally increasing the volume of the pleural cavity. Farmer and Carrier (2000) further showed that the kinetic pelvis also contributes to breathing in crocodilians. Pelvic muscle activities were correlated with both inspiration (with M. ischiopubis and M. ischiotruncus rotating the pubes ventrally increasing abdominal volume) and expiration (with the M. rectus abdominis and M. transversus abdominis rotating the pubes dorsally). Activation of these four pelvic muscles are independent of locomotion and were presumed to be primarily for breathing function. This allows for a strong breathing capability independent

Carnotaurus sastrei

I got a request from Zach to draw Carnotaurus so here is my attempted reconstruction of C. sastrei . Funnily enough I have never drawn or even attempted to draw Carnotaurus previous to this - that is except for the unsatisfactory precursor to this picture...It took me forever to finish but for a first attempt I kinda think it turned out pretty good. There are some really strange things with Carnotaurus , the first obvious being the skull. Staring at Bonaparte et al.'s (1990) skull reconstruction and photos for a prolonged time and reading their description, I noticed that the postorbital region of the skull in Carnotaurus is really strongly deflected ventrally while the sagittal crest is extremely high. This results in the supratemporal fenestrae having their lateral borders ventrally displaced compared to the medial borders. The sagittal crest in reptiles generally serves as the attachment sites for jaw adductor muscles, namely the M. pseudotemporalis superficialis (MPsTs), M.