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Macrophagous teleosaurid crocodylomorphs in Late Jurassic of UK

Ben Creisler

A new paper:

Davide Foffa, Mark T. Young & Stephen L. Brusatte (2015)
Evidence of macrophagous teleosaurid crocodylomorphs in the Corallian
Group (Oxfordian, Late Jurassic) of the UK.
PeerJ 3:e1497
doi:  https://doi.org/10.7717/peerj.1497

Teleosaurids were a group of semi-aquatic crocodylomorphs with a
fossil record that spanned the Jurassic Period. In the UK, abundant
specimens are known from the Oxford Clay Formation (OCF, Callovian to
lower Oxfordian), but are very rare in the Kimmeridge Clay Formation
(KCF, Kimmeridgian to lower Tithonian), despite their abundance in
some contemporaneous deposits in continental Europe. Unfortunately,
due to the paucity of material from the intermediate ‘Corallian Gap’
(middle to upper Oxfordian), we lack an understanding of how and why
teleosaurid taxic abundance and diversity declined from the OCF to the
KCF. The recognition of an incomplete teleosaurid lower jaw from the
Corallian of Weymouth (Dorset, UK) begins to rectify this. The
vertically oriented dentition, blunt tooth apices, intense enamel
ornamentation that shifts to an anastomosed pattern apically, and deep
reception pits on the dentary unambiguously demonstrates the affinity
of this specimen with an unnamed sub-clade of macrophagous/durophagous
teleosaurids (‘Steneosaurus’ obtusidens + Machimosaurus). The high
symphyseal tooth count allows us to exclude the specimen from M. hugii
and M. mosae, but in absence of more diagnostic material we cannot
unambiguously assign DORCM G.3939 to a more specific level.
Nevertheless, this specimen represents the first mandibular material
referable to Teleosauridae from the poorly sampled middle-upper
Oxfordian time-span in the UK.