New paper (request)

["Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>]

Yesterday, _Eocursor_ and _Gigantotoraptor_. Today, the sauropods are 
represented by:

Schwarz, D., Ikejiri, T., Breithaupt, B. H., Sander, P. M. & Klein, N. 2007. A 
nearly complete skeleton of an early juvenile
diplodocid (Dinosauria: Sauropoda) from the Lower Morrison Formation (Late 
Jurassic) of north central Wyoming and its implications
for early ontogeny and pneumaticity in sauropods. Historical Biology 19, 
225-253.

Abstract
A nearly complete skeleton of a juvenile sauropod from the Lower Morrison 
Formation (Late Jurassic, Kimmeridgian) of the Howe Ranch
in Bighorn County, Wyoming is described. The specimen consists of articulated 
mid-cervical to mid-caudal vertebrae and most
appendicular bones, but cranial and mandibular elements are missing. The 
shoulder height is approximately 67 cm, and the total body
length is estimated to be less than 200 cm. Besides the body size, the 
following morphological features indicate that this specimen
is an early juvenile; (1) unfused centra and neural arches in presacral, sacral 
and first to ninth caudal vertebrae, (2) unfused
coracoid and scapula, (3) open coracoid foramen, and (4) relatively smooth 
articular surfaces on the limb, wrist, and ankle bones. A
large scapula, short neck and tail and elongate forelimb bones relative to 
overall body size demonstrate relative growth. A
thin-section of the mid-shaft of a femur shows a lack of annual growth lines, 
indicating an early juvenile individual possibly
younger than a few years old. Pneumatic structures in the vertebral column of 
the specimen SMA 0009 show that pneumatisation of the
postcranial skeleton had already started in this individual, giving new 
insights in the early ontogenetic development of vertebral
pneumaticity in sauropods.

The specimen exhibits a number of diplodocid features (e.g., very elongate 
slender scapular blade with a gradually dorsoventrally
expanded distal end, a total of nine dorsal vertebrae, presence of the 
posterior centroparapophyseal lamina in the posterior dorsal
vertebrae). Although a few diplodocid taxa, Diplodocus, cf. Apatosaurus, and 
cf. Barosaurus, are known from several fossil sites
near the Howe Ranch, identification of this specimen, even at a generic level, 
is difficult due to a large degree of ontogenetic
variation.

[We don't get Historical Biology here, so if someone would be so kind...? 
Thanks in advance.]

                Thomas R. Holtz, Jr.
        Senior Lecturer, Vertebrate Paleontology
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
        Mailing Address:
                Building 237, Room 1117
                College Park, MD  20742

http://www.geol.umd.edu/~tholtz/
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796