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Theropod teeth from Middle Jurassic of Niger

Ben Creisler

A new paper:

Alejandro Serrano-Martínez, Daniel Vidal, Lara Scisio, Francisco
Ortega, and Fabien Knoll (2015)
Isolated theropod teeth from the Middle Jurassic of Niger and the
early dental evolution of Spinosauridae.
Acta Palaeontologica Polonica (in press)

Four isolated theropod teeth from the ?Bathonian “Argiles de
l’Irhazer” in Niger are described. The teeth were  found in
association with the holotype of the basal sauropod Spinophorosaurus
nigerensis. These specimens have been assigned to two different taxa
by independent analyses, such as direct comparison with teeth
previously described in the literature, discriminant and morphometric
analyses from metric characters, and cladistic and cluster analyses
from discrete characters. The results suggest that three teeth share
affinities with those of  Megalosauridae and Allosauridae, belonging
most likely to the former. The fourth tooth might be from a member of
the stem group Spinosauridae. If so, this would be the oldest
representative of this clade. This tooth shows a combination of
characters that are unusual in typical spinosaurid teeth (crown
moderately compressed labiolingually and curved distally with minute
denticles on the carina and a deeply veined enamel surface texture
without apicobasal ridges), which could shed light on the
morphological transition from the plesiomorphic ziphodont dental
pattern to that of Spinosauridae. This tooth would also allow a better
understanding of the origin of the spinosaurids, supporting a
Gondwanan origin for the group.