A new paper:
The attachments of jaw muscles are typically implicated in the evolution and shape of the dorsotemporal fenestra on the skull roof of amniotes. However, the dorsotemporal fenestrae of many archosaurian reptiles possess smooth excavations rostral and dorsal to the dorsotemporal fossa which closely neighbors the dorsotemporal fenestra and jaw muscle attachments. Previous research has typically identified this region, here termed the frontoparietal fossa, to also have been attachment surfaces for jawâclosing muscles. However, numerous observations of extant and extinct archosaurs described here suggest that other tissues are instead responsible for the size and shape of the frontoparietal fossa. This study reviewed the anatomical evidence that support softâtissue hypotheses of the frontoparietal fossa and its phylogenetic distribution among sauropsids. Softâtissue hypotheses (i.e., muscle, pneumatic sinus, vascular tissues) were analyzed using anatomical, imaging and in vivo thermography techniques within a phylogenetic framework using extant and extinct taxa to determine the inferential power underlying the reconstruction of the soft tissues in the skull roofs of dinosaurs, pseudosuchians and other reptiles. Relevant anatomical features argue for rejection of the default hypothesis--that the fossa was muscular--due to a complete lack of osteological correlates reflective of muscle attachment. The mostâsupported inference of soft tissues is that the frontoparietal fossa contained a large vascular structure and adipose tissue. Despite the large sizes and diverse morphologies of these fossae found among dinosaur taxa, these data suggest that nonâavian dinosaurs had the anatomical foundation to support physiologicallyâsignificant vascular devices and/or vascular integumentary structures on their skull roofs.