[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Dyrosaurid (Crocodyliformes) feeding apparatus



From: Ben Creisler
bcreisler@gmail.com


A new online paper:

Daniela Schwarz-Wings (2013)
The feeding apparatus of dyrosaurids (Crocodyliformes).
Geological Magazine (advance online publication)
DOI: http://dx.doi.org/10.1017/S0016756813000460
http://128.232.233.5/action/displayAbstract?fromPage=online&aid=8976904&fulltextType=RA&fileId=S0016756813000460



Reconstructed soft-tissues of the craniocervical region of dyrosaurids
are analysed under functional aspects to determine their prey-catching
capabilities. Jaw adductors and jaw abductors are enlarged and possess
longer muscle fibres that are increased by a long retroarticular
process. This muscle enlargement resulted in a more forceful and
quicker contraction, effective for movement of the long rostrum. The
occipital joint and the cervical ribs, the long retroarticular process
and the high cervical neural spines of dyrosaurids suggest a higher
dorsoventral flexibility of the craniocervical region, whereas
lateromedial flexibility was reduced. The epaxial muscles of the neck
and scapular muscles were enlarged, and the supraspinal ligament most
likely fanned out into a nuchal ligament. Suspension of the neck and
skull of dyrosaurids was achieved by the scapular muscles, dorsal neck
ligaments and epaxial muscles, whereas ventral bracing was reduced.
>From the reconstructed specializations of the feeding apparatus, an
enhanced capability for movements in the vertical plane is postulated
for dyrosaurids, together with reduced lateral movements of the
craniocervical region. Besides laterally directed strokes for
fish-catching, behaviours such as poking in the substrate, bottom
feeding, multidirectional prey-catching strokes and improvement of
diving skills were options for dyrosaurids and suggest a possible
expansion of their diet. The longirostrine skull limited prey size,
but the dentition allowed shelly prey items. The specialization of the
food-capturing system in dyrosaurids and the resulting expansion of
their food spectrum is one possible explanation for their evolutionary
success, including their undisturbed transition of the
Cretaceous–Palaeogene boundary.