Re: Lagosuchus/Marasuchus

["Jaime A. Headden" <qilongia@yahoo.com>]

John Conway (john_conway@mac.com) wrote:

<Could anyone advise me on the _Lagosuchus_/_Marasuchus _ situation, and 
the etymology of _Marasuchus_?>

  *Lagosuchus talampayensis* is a taxon based on only hindlimb material
and some pelvic elements. Bonaparte described a new species to Romer's
genus and labelled it *Lagosuchus lilloensis*. However, the material is
that of a nearly complete taxon, and in the early 1990's, Andrea Arcucci
expressed doubts about the relationship of *L. lilloenis* to *Lagosuchus*,
especially in regards to the diagnostic value of the *Lagosuchus
talampayensis* holotype, and in 1994, Sereno and Arcucci redescribed the
species as *Marasuchus lilloensis*, and indicated that the holotype of
*Lagosuchus* (now monotypic) was in fact devoid of apomorphies, and
referred it to a nomen dubium. While this may be true based on present
knowledge, it is more than likely that *Lagosuchus* and *Marasuchus*
represent congeneric taxa; problematically, the type species was not found
to be diagnostic, and any other included (and diagnostic) species must be
renamed to reflect this.

  *Marasuchus* is named for the rodent, called a mara, which resembles a
rabbit, and was intended to retain the "spirit" of Alfred Romer's name
(*Lagus*, a rabbit, from the Latin for "rabbit").

  All restorations of *Lagosuchus* are based on the lilloensis material,
and it would be fair and easy to use this to represent *Marasuchus*. Note,
in 1988, Paul considers *M. lilloensis* con_specific_ with *L.
talampayensis*, though most other authors now separate the two and agree
with Sereno and Arcucci.

 ---

  Note, this is not intended as an evaluation of the type material of
*Lagosuchus talampayensis*.

  Cheers,

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

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