[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

RE: New Santana theropod



Thanks, Tracy, for alerting us the the paper!
 
Martill et al. questionably refer the material to Compsognathidae, on the basis of the shape of the pubic boot and its fan-shaped  neural spines of the dorsals.
 
The possible postpubic air sac is an vacuity in the matrix extending from the dorsal aspect of the pubic boot and extends half-way to the ischium. It was partially lined with small calcite crystals.  They reject the possibility this structure might represent the mold of a urinary bladder or ovaries, as these would be wholly anterior to the pubis or between the sacrum & the pubis.
 
Unfortunately the authors do not make direct comparisons to _Santanaraptor_ (which may not have been described when this paper was written).
 
In the same issue, a paper on the Jurassic time scale:
Palfy, J., P.L. smith & J.K. Mortensen.  2000.  A U-Pb and 40Ar/39Ar time scale for the Jurassic.  CJES 37: 923-944.
 
Here are their new stage-boundary dates.  Note that the Jurassic as a whole has been shrunk, as has the Late Jurassic relative to the Early & Middle.  Dates given are the lower time boundary for each unit:
Berriasian (J-K boundary):    141.8 +2.5 -1.8
Tithonian:    150 +3.4 -2.8
Kimmeridgian:    154.7 +3.8 -3.3
Oxfordian:    156.5 +3.1 -5.1
Callovian:    160.4 +1.1 -0.5
Bathonian:    166.0 +3.8 -5.6
Bajocian:    174.0 +1.2 -7.9
Aalenian:    178.0 +1.0 -1.5
Toarcian:    183.6 +1.7 -1.1
Pliensbachian:    191.5 +1.9 -4.7
Sinemurian:    196.5 +1.7 -5.7
Hettangian (Tr-J boundary):    199.6 +_0.4
 
Dates in Ma, uncertainty in Myr.
 
 

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742      
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-314-7843

-----Original Message-----
From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of Tracy Ford
Sent: Saturday, August 05, 2000 6:07 PM
To: Dinonet
Subject: New Santana theropod

Well, since no one has mentioned this on the list yet (I think), a new theropod from the Santana Formation (Romualdo Member) from Araripina region (precise locality unknown) is described (not named) by Martill, Frey, Sues and Cruickshank, 2000.

 

It has almost the same material that Santanaraptor has (partial ilium, pubis, ischium, femora, distal ends of fibula and tibia, sacral vertebrae), but the elements aren’t the same shape. Also they believe there might be remnants of a segment of a lithified intestinal tract and a postpubic air sac.

 

More internal guts of dinosaurs.

 

Martill, David M., Eberhard Frey, Hans-Deuter Sues, and Arthur R. I. Cruickshank, 2000. Skeletal remains of a small theropod dinosaur with associated soft structures from the Lower Cretaceous Santana Formation of northeastern Brazil. Can. J. Earth Sci., Volume 37: 891-900.

 

Tracy