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Lunge-feeding early marine reptiles + Oligokyphus from Upper Triassic of Nova Scotia



Ben Creisler
bcreisler@gmail.com


Two recent papers not yet mentioned:


Ryosuke Motani, Xiao-hong Chen, Da-yong Jiang, Long Cheng, Andrea
Tintori & Olivier Rieppel (2015)
Lunge feeding in early marine reptiles and fast evolution of marine
tetrapod feeding guilds.
Scientific Reports 5, Article number: 8900
doi:10.1038/srep08900
http://www.nature.com/srep/2015/150310/srep08900/full/srep08900.html

Free pdf:
http://www.nature.com/srep/2015/150310/srep08900/pdf/srep08900.pdf


Traditional wisdom holds that biotic recovery from the end-Permian
extinction was slow and gradual, and was not complete until the Middle
Triassic. Here, we report that the evolution of marine predator
feeding guilds, and their trophic structure, proceeded faster. Marine
reptile lineages with unique feeding adaptations emerged during the
Early Triassic (about 248 million years ago), including the enigmatic
Hupehsuchus that possessed an unusually slender mandible. A new
specimen of this genus reveals a well-preserved palate and mandible,
which suggest that it was a rare lunge feeder as also occurs in
rorqual whales and pelicans. The diversity of feeding strategies among
Triassic marine tetrapods reached their peak in the Early Triassic,
soon after their first appearance in the fossil record. The diet of
these early marine tetrapods most likely included soft-bodied animals
that are not preserved as fossils. Early marine tetrapods most likely
introduced a new trophic mechanism to redistribute nutrients to the
top 10 m of the sea, where the primary productivity is highest.
Therefore, a simple recovery to a Permian-like trophic structure does
not explain the biotic changes seen after the Early Triassic.


==


Tim J Fedak, Hans-Dieter Sues & Paul P.E. Olsen (2015)
First record of the tritylodontid cynodont Oligokyphus and cynodont
postcranial bones from the McCoy Brook Formation of Nova Scotia,
Canada.
Canadian Journal of Earth Sciences (advance online publication)
doi: 10.1139/cjes-2014-0220
http://www.nrcresearchpress.com/doi/abs/10.1139/cjes-2014-0220?src=recsys#.VQbs9I7F_To

A fragment of a right dentary with one postcanine tooth from the Upper
Triassic (Rhaetian) Scots Bay Member of the McCoy Brook Formation at
Wasson Bluff, Nova Scotia (Canada), represents the first record of the
tritylodontid cynodont Oligokyphus from the early Mesozoic of eastern
North America. In addition, three dissociated postcranial bones from
the same horizon and locality are referable to derived cynodont
therapsids. One of these elements, a nearly complete right humerus,
can be assigned to Tritylodontidae. Two other bones, an ulna and
incomplete ischium, belong to indeterminate derived cynodonts but show
no features allowing more precise taxonomic identification. The
presence of Oligokyphus in the McCoy Brook Formation provides
additional evidence for the remarkably wide geographic distribution of
many latest Triassic and Early Jurassic continental tetrapods.