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2005's Taxa Still Counting...



  A paper from last year about a Konversat-Lagerstätte from the Cenomanian of
Coahuila, Mexico (near the southern tip of Texas, and part of the Austin
Group). The paper is a largely lithologic study of the region and it's
conserved dating based on forams and suchlike. But they also report on the
fauna associated with the typical dating organisms, and this includes a nearly
complete pterosaur.

  But first, the paper:

  Stinnesbeck, W., C. Ifrim, H. Schmidt, A. Rindfleisch, M.-C.
   Buchy, E. Frey, A. H. González-González, F. J. Vega, L. Cavin,
   G. Keller, and K. T. Smith. 2005. A new lithographic limestone
   deposit in the Upper Cretaceous Austin Group at El Rosario,
   county of Múzquiz, Coahuila, northeastern Mexico. _Revista
   Mexicana de Ciencias Geológicas_ 22(3):401-418.

Abstract:
  "At El Rosario, 170 km WNW of Múzquiz in northern Coahuila,
   Mexico, alternating evenly layered platy limestone and fissile
   marly limestone of late Turonian-early Coniacian age (Late
   Cretaceous) contain vertebrate fossils with exceptionally
   well-preserved anatomical details of their soft tissues, as
   well as abundant ammonoids, inoceramids and other
   invertebrates. Deposition was in an open marine shelf
   environment near the southern opening of the Western Interior
   Seaway, several hundreds of kilometers south of the North
   American coastline, in water depths of at least 50-100 m. The
   present research intends to highlight the enormous
   reservational potential of this new conservation deposit
   (Konservat-Lagerstätte) and to analyze the paleoenvironmental
   conditions present at this locality. Our preliminary data
   suggest that the El Rosario fossil deposit is a combined result
   of anoxic bottom conditions, early diagenetic phosphatization,
   and rapid burial in a soft, micritic lime mud."

  However, the paper goes on to do something that I am sure could have been
avoided if they had either 1) waited for the paper, or 2) ommited the
nomenclature. The latter might have been the easier course, and the safest bet.
On with the quoting:

  Pg. 408:
  "Pterosaurs
   The only known pterosaur specimen is an almost complete and
   articulated nyctosaurid pterosaur, which is under detailed
   study by Frey et al. (in press) and referred to a new genus and
   species, *Muzquizopteryx coahuilensis*. With a wingspan of
   about 2 m, it represents the smallest known adult nyctosaurid
   pterosaur. Due to the fact that the specimen comes from the
   earliest Coniacian (see below), it represents the earliest
   known nyctosaurid. The preservation of soft parts and the in
   situ preservation of the carpus allows the reconstruction of
   some distal arm muscles and a definite conclusion regarding the
   orientation of the pteroid bone."

  Figure 5d-f on page 409 illustrates a caudal series of a mosasaur and also
this new pterosaur:

  "Figure 5. a-d: Undetermined squamate, partial caudal vertebra
   (PAS 337) from El Rosario, in (a) dorsal, (b) ventral), (c)
   right lateral and (d) caudal views. e: Undetermined mosasaur,
   PAS 336, from El Rosario, in right lateral view, ×0.5. f:
   Nyctosaurid pterosaur (UNAM IGM 8621) *Muzquizopteryx
   coahuilensis* n.gen., n.sp., which is currently described by
   Frey et al. (in press). Scale bars 10 mm."

  Normally, I'd be happy if this was a preliminary study and nomenclatural act
with the intent to introduce a new name to the fossil record, but it is clear
they are applying the name to a future act (the "in press" comments).
Unfortunately, the paper is likely available for the use of nomenclature, and
the authors are likely the proud new owners of a nomen nudum, though I am sure
that Dino Frey, recent star of his 3m "wing bone" and the giant tracks from
Mexico on _Sky Monsters_ (which seriously could have been better, though I
enjoyed the parts where Sereno was unveiling his ornithocheiroid wing, and the
Stanford group was assembling their flapper machine with the helpful assistance
of listmember Jim Cunningham, and Padian's answer to a query I had in October,
2004, wherein he has changed his stance on pterosaur posture [forgive the pun]
due to the landing tracks that were presented at the SVP before last).

  Hopefully the paper will whet our appetites for the real study and work by
Frey, which should be out soon. Then I looked at the cite:

  "Frey, E., M.-C. Buchy, W. Stinnesbeck, A. H. González-González,
   and A. di Stefano. in press. *Muzquizopterix coahuilensis*
   n.g., n.sp., first evidence for the presence of nyctosaurid
   pterosaurs in the Coniacian (Late Cretaceous) of northeastern
   Mexico (Coahuila). _Oryctos_."

  _Oryctos_. The same journal whose latest issue has been in press for a number
of years now. Let us hope!

  Cheers,

Jaime A. Headden

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

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