Lagosuchus (was RE: PDF-request: Original description of Lagosuchus and/or Marasuchus)

[Tim Williams <tijawi@yahoo.com>]

Jaime Headden <qi_leong@hotmail.com> wrote:

> It was the argument of Sereno and Arcucci that
> *Lagosuchus chanarensis* lacked apomorphies which would
> allow any other species/specimen to be attributed to
> *Lagosuchus*, prompting the move. This argument has been
> followed, but not tested, in print since it's conception.


As mentioned, Jaime meant to say _Lagosuchus talampayensis_ here (_L. 
talampayensis_ being the type species for _Lagosuchus_).  But I agree that we 
shouldn't give up on _Lagosuchus_.


Sereno and Arcucci (1994) regarded _Lagosuchus_ as a nomen dubium, because the 
holotype (UPLR 09) is a fragmentary (but largely articulated) postcranium that 
lacks autapomorphies.  


However, it is possible that _Lagosuchus_ can be diagnosed by a unique 
combination of characters.  The _Lagosuchus_ holotype (UPLR 09) can certainly 
be distinguished from _Marasuchus_, especially in the shape of the scapula.  
(This assumes that the referred forelimb material indeed belongs to the 
holotype; but this seems highly likely based on its size, morphology, and 
preserved position relative to the rest of the skeleton; see Sereno and 
Arcucci, 1994 Fig. 1).


So maybe all is not lost for _Lagosuchus_.   Although it appears to have no 
unique characters, I'd like to see if it can be diagnosed based on a unique 
*combination* of characters.

 
Cheers

Tim