SVP 2011 Roundup - Crocodylomorph Edition Part 1

General Crocodylomorph Ecology and Evolution

(in order of presentation)

Talks

"Campanian crocodyliforms of Laramidia: new insights from the Kaiparowits Basin of southern Utah." Irmis, R., Sertich, J., Hutchison, J. H., And Titus, A.

• comprehensive survey of Kaiparowits crocodyliforms
• large, goniopholidid-like mesoeucroc.
• basal alligatorids: Deinosuchus hatcheri and Brachychampsa
• small alligatoroid lacking globidont teeth
• clear biogeographic relationship with the San Juan Basin (New Mexico) - some regionality but also endemic taxa
• supports the hypothesis of a distinct southern biogeographic province

"Direct evidence of crocodyliform predation on small dinosaurians from the Kaiparowits Formation of Utah." Drumheller, S. and Boyd, C.

• predation by a small crocodyliform on a juvenile basal ornithopod (new Hypsolophodont)
• several bite marks characteristic of crocs
• partial tooth embeded in femur (distal tip had been broken off previously)

"The myth of the living fossil: basal crown group relationships, reversing polarities, and restoration of the ancestral crocodylian." Brochu, C., Turner, A., Allen, E., and Wilberg, E.

• outgroups of Crocodylia predominantly small bodied (less than 2 meters)
• the crocodylian ancestral condition was likely equivalent to the small durophagous alligatorines of the Paleogene
• living crocodylians are not generalized but independently highly specialized (NOT LIVING FOSSILS!!!!)

Posters

"Freshwater niche competition between choristoderes and crocodiles in the Mesozoic and Paleogene." Matsumoto, R.

• Early Cretaceous of Asia - high diversity of choristoderes, no aquatic crocs
• Middle Jurassic thru Eocene of Europe - only small lizard-like choristoderes, co-occuring with larger crocs
• Cretaceous thru Paleogene of Euramerica - neochoristoderes co-occur with similar sized crocs, but neochoristoderes are the only strongly longirostrine reptiles
• long-snouted crocs diversify in freshwater after the extinction of neochoristoderes (Oligo-Miocene)

"Late Neogene Alligator evolution and a description of specimens from the Gray Fossil Site, southern appalachians, USA." Schubert, B., Mead, J., and Stout, J.

• abundant Alligator material
• osteroderms and other fragmentary material
• mostly complete juvenile
• pathological adult skull
• two adult partial post-cranial skeletons
• Alligator of Gray Fossil Site posses a mixture of characters found in A. olseni, A. mefferdi, and A. mississippiensis

"Crocs not theropods were likely top predators on the Cretaceous dinosaur freeway: implications of a large track census." Lockley, M. and Lucas, S.

• at least 1380 individual trackmakers
• mostly ornithopods (71%)
• only small theropods present (not large enough to prey on ornithopods)
• abundant crocodylian tracks (walking and swimming), including large individual (around 4 meters)

"A taphonomic and paleoecological comparison of isolated crocodyliform teeth from the Woodbine Formation of Texas and the Hell Creek Formation of Montana." Bennett, G., Main, D., Peterson, R., and Anderson, B.

• 4 different crocodyliforms in the Woodbine Formations, including Woodbinesuchus and a new genus
• 2 different crocodyliforms in the Hell Creek (Brachychampsa montana and Borealosuchus sternbergi), showing similar population structure to A. mississippiensis.