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Re: Astrodon vs Pleurocoelous

Alan Blake Coulson wrote:

Does anyone know the current status of these taxa? I seem to remember
hearing that someone had consolidated the 3(?) Pleurocoelous species into
1 or 2, and that they were distinct from Astrodon, but I cannot remember
the source.

If Salgado and co are correct, no less than THREE sauropod genera are represented from among the Lower Cretaceous North American material traditionally named "Pleurocoelus". According to recent research (which is still in progress)...

(1) _Pleurocoelus nanus_ (type species, from the Arundel Formation of
Maryland) is a brachiosaurid (or at least outside the Titanosauria); it shows a few titanosauriform synapomorphs (absence of phalangeal articular surfaces on the distal metacarpals; transversely expanded distal tibia), but its anterior caudal vertebrae are amphiplatyan, not procoelous.

(2) _P. altus_ (also from the Arundel Fm) is NOT an adult _P. nanus_; it probably does not even belong in the same genus. _P. altus_ "exhibits an anteroposteriorly expanded distal tibia, a character which is plesiomorphic for sauropods."

(3) The _Pleurocoelus_ material from the Comanche Series of Texas,
definitely does NOT belong in the genus _Pleurocoelus_. Its anterior
caudals are weakly procoelous. Based on this and other features, the Comanche sauropod may be a basal titanosaur, and possibly the same as _Cedarosaurus_.

As for _Astrodon_, its based on teeth that are considered to belong to an undetermined sauropod. Thus _Pleurocoelus_ is probably not referrable to _Astrodon_.

Hope this helps.


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