Re: Where to put *Scleromochlus*?

["Mickey Mortimer" <Mickey_Mortimer11@msn.com>]

David Marjanovic wrote-

> Now that pterosaurs have been moved away, *Scleromochlus taylori* finds
> itself in Dinosauromorpha... but where exactly? Suggestions?

It would be the most basal form, if it is a member.  Scleromochlus lacks two
Lagerpeton+Dinosauriformes synapomorphies- metatarsal V with articular
surface for distal tarsal IV oriented parallel to shaft axis; mid-shaft
diameters of metatarsals I and V less than those of II-IV.  It also lacks
three dinosauriform synapomorphies- cerivical column following strong
sigmoid curve; anterior trochantor present; trochanteric shelf present.  It
does have one dinosauriform character though- distal tibia quadrangular,
with medial and posterior surfaces forming obtuse angle distally.  Finally,
it lacks a pubis more then 70% of femoral length, excluding it from the
Pseudolagosuchus-Dinosauria clade.  Remember though, Scleromochlus has
several characters in common with pterosaurs.  Assuming pterosaurs are not
archosaurs, could Scleromochlus be close to Cosesaurus, Sharovipteryx and
such?  Any thoughts from Dave Peters?

Mickey Mortimer