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RE: Pegomastax, new heterodontosaurid from South Africa in new Sereno monograph (free pdf!)
And here I thought Butler was redescribing heterodontosaurids...
In general, this is an excellent paper with numerous useful photographs and
illustrations (well, besides the bobble-headed Tianyulong-
But I can't wrap my head around Sereno's dismissal of Geranosaurus-
"Geranosaurus atavus, nonetheless, differs in several regards from
Heterodontosaurus tucki, which also occurs in the Clarens Formation, and from
heterodontosaurids from the underlying Upper Elliot Formation. The dentary
tooth row in Geranosaurus atavus appears to be composed of eight subequal
postcaniniform teeth arranged along a medially bowed tooth row (Fig. 2B). In
Heterodontosaurus, in contrast, there are 11 or 12 dentary teeth that increase
in size toward the center of a relatively straight tooth row. Abrictosaurus
also has a higher tooth count and size differential along the dentary tooth
row, as well as a relatively smaller caniniform tooth. Unlike Heterodontosaurus
and Lycorhinus, a postcaniniform diastema is not present in Geranosaurus
atavus, as the second tooth positioned adjacent to the caniniform tooth (Fig.
2B). Crompton and Charig (1962) cited the absence of an arched
premaxilla-maxillary diastema in Geranosaurus atavus to differentiate
Geranosaurus atavus, although this portion of the upper jaw does not appear to
have been preserved.
Recently Norman et al. (2011) concluded that Geranosaurus atavus cannot be
distinguished by a “unique combination of characters”. Although not adequate to
justify taxonomic recognition, the features exhibited by Geranosaurus atavus
and discussed above clearly suggest there is a second heterodontosaurid taxon
in the Clarens Formation in addition to Heterodontosaurus tucki."
So it's distinctive from other heterodontosaurids and already has a name, yet
it is "not adequate to justify taxonomic recognition." Er...
> Date: Wed, 3 Oct 2012 09:19:17 -0700
> From: email@example.com
> To: firstname.lastname@example.org
> Subject: Pegomastax, new heterodontosaurid from South Africa in new Sereno
> monograph (free pdf!)
> From: Ben Creisler
> A new taxon in a new monograph at ZooKeys site. The pdf is free!
> Paul Sereno (2012)
> Taxonomy, morphology, masticatory function and phylogeny of
> heterodontosaurid dinosaurs.
> ZooKeys 224: 1-225.
> doi: 10.3897/zookeys.224.2840
> Heterodontosaurids comprise an important early radiation of
> small-bodied herbivores that persisted for approximately 100 My from
> Late Triassic to Early Cretaceous time. Review of available fossils
> unequivocally establishes Echinodon as a very small-bodied,
> late-surviving northern heterodontosaurid similar to the other
> northern genera Fruitadens and Tianyulong. Tianyulong from northern
> China has unusual skeletal proportions, including a relatively large
> skull, short forelimb, and long manual digit II. The southern African
> heterodontosaurid genus Lycorhinus is established as valid, and a new
> taxon from the same formation is named Pegomastax africanus gen. n.,
> sp. n. Tooth replacement and tooth-to-tooth wear is more common than
> previously thought among heterodontosaurids, and in Heterodontosaurus
> the angle of tooth-to-tooth shear is shown to increase markedly during
> maturation. Long-axis rotation of the lower jaw during occlusion is
> identified here as the most likely functional mechanism underlying
> marked tooth wear in mature specimens of Heterodontosaurus. Extensive
> tooth wear and other evidence suggests that all heterodontosaurids
> were predominantly or exclusively herbivores. Basal genera such as
> Echinodon, Fruitadens and Tianyulong with primitive, subtriangular
> crowns currently are known only from northern landmasses. All other
> genera except the enigmatic Pisanosaurus have deeper crown proportions
> and currently are known only from southern landmasses.
> new release with video:
> (NOTE: One glitch in the name : mastax "jaw" is feminine in Greek so
> the name should be Pegomastax africana to follow the letter of the