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Jurassic teleosaurid with denticulated dentition

From: Ben Creisler

A new online paper:

Mark T. Young, Brian L. Beatty, Stephen L. Brusatte, and Lorna Steel (2013)
First evidence of denticulated dentition in teleosaurid crocodylomorphs
Acta Palaeontologica Polonica (in press)

Teleosauridae was a group of largely marine Mesozoic crocodylomorphs,
typically considered as akin to “marine gavials” due to their
elongate, tubular, polydont rostra that are indicative of a
piscivorous diet. We here show that these extinct crocodylomorphs were
more anatomically, and perhaps ecologically, varied than previously
thought. We report the first evidence of denticles in a teleosaurid
tooth, revealed by scanning electron microscopic (SEM) analysis of a
tooth from the holotype of "Steneosaurus" obtusidens. These denticles
are cryptic, because they are microscopic, not contiguous along the
carinae (instead forming short series), and are detectable only using
SEM. This incipient denticle morphology is similar to that recently
discovered in a closely related group of marine crocodylomorphs, the
Metriorhynchidae. In particular, the denticulation morphology of
"Steneosaurus" is similar to that of the geosaurin metriorhynchid
Torvoneustes, indicating that these two taxa may have employed similar
feeding styles and that "S."obtusidens may have been a nearshore
ecological analogue to the more offshore, fast-swimming geosaurins.
Previous authors have considered "S." obtusidens and Machimosaurus to
be durophagous, but the discovery of denticulated teeth indicates that
they had a more varied diet and feeding style, and included flesh
slicing as part of their feeding toolkit. It is currently unknown how
extensive denticulate carinae may be in Teleosauridae, and we
hypothesise that cryptic denticles may also be present in other marine
crocodylomorphs once they are subjected to SEM study.