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Re: New *Anchisaurus* paper
Yates, A.M., 2004. *Anchisaurus polyzelus* (Hitchcock): The Smallest Known
Sauropod Dinosaur and the Evolution of Gigantism among Sauropodomorph
Dinosaurs. Postilla 230: 58 pp.
I just read this over the weekend. Nice work by Adam.
A few tidbits that stuck in my memory:
The phylogenetic position of _Herrerasaurus_ flip-flops between inside and
outside the Theropoda, and Yates (2004) suggests that the theropod-like
characters of _H._ (e.g., intramandibular hinge; elongate grasping/raking
manus) may be due to convergence, and associated with a hypercarnivorous
ecology for _H._.
_Mussaurus_ (which has procumbent teeth in the upper and lower jaws) shows
many non-prosauropod-like characters, and so is unlikely to be a
_Ammosaurus_ is sunk into _Anchisaurus_, and the differences previously used
to separate the two genera are attributed to size/ontogeny (e.g.,
"broad-footed" _Ammo_ vs "narrow-footed' _Anchi_) and postmortem damage to
At least two sauropodomorph taxa are known from the Early Jurassic of New
England: the basal sauropod _Anchisaurus polyzelus_ (including _Ammosaurus
major_, _Yaleosaurus colurus_) and another taxon (previously referred to
_colurus_) that differs from _Anchisaurus_ in the morphology of the manus.
This second taxon shows affinities to the Plateosauria, and is therefore a
true prosauropod (sensu Yates).
The _Ammosaurus_ material from the Navajo Sandstone of Arizona does not
belong to _Anchisaurus_, but to a prosauropod that is possibly related to
_Massospondylus_. (Interesting, massospondylid material has been previously
described from Arizona, but from the Kayenta Formation)
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