Contrarian View: Did Pterosaurs NOT Breathe Like Birds?

Breathing in a box: Constraints on lung ventilation in giant pterosaurs

Authors:

Giest et al

Abstract:

Pterosaurs were the first vertebrates to achieve active flight, with some derived forms reaching enormous size. Accumulating fossil evidence confirms earlier indications that selection for large size in these flying forms resulted in a light, yet strong skeleton characterized by fusion of many bones of the trunk. However, this process also added mechanical constraints on the mobility of the thorax of large pterosaurs that likely limited the options available for lung ventilation. We present an alternative hypothesis to recent suggestions of an avian-like mechanism of costosternal pumping as the primary means of aspiration. An analysis of the joints among the vertebrae, ribs, sternum, and pectoral girdle of large pterosaurs indicates limited mobility of the ribcage and sternum. Comparisons with modes of lung ventilation in extant amniotes suggests that the stiffened thorax, coupled with mobile gastralia and prepubic bones, may be most consistent with an extracostal mechanism for lung ventilation in large pterodactyloids, perhaps similar to a crocodile-like visceral displacement system.

Two bits.  I thought crocs did breathe like birds?  And given iguanas and monitors are supposed to as well, that strikes me as the likelihood is the bird-breathing scheme is basal to diapsids.  I am waiting to see what Mark and Darren state about this...