Destiny of the New Papers

[Tim Williams <twilliams_alpha@hotmail.com>]

I haven't clapped eyes on any of these papers yet...

Schwarz, D., Ikejiri, T., Breithaupt, B.H., Sander, P.M., and 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."


And for the choristodere fans...

Ke-Qin Gao, Ksepka, D., Hou Lianhai, Duan Ye, and Hu Dongyu (2007).  Cranial 
morphology of an Early Cretaceous monjurosuchid (Reptilia: Diapsida) from 
Liaoning Province of China and evolution of the choristoderan palate.  
Historical Biology 19: 215-224.

Abstract: "A new specimen of _Philydrosaurus proseilus_ from the Early 
Cretaceous Chiufotang (Jiufotang) Formation preserves the first complete 
palate of a monjurosuchid choristodere.  As in other choristoderes, the 
palate of _Philydrosaurus_ is akinetic, extended by a broad contact between 
the vomer and maxilla, and equipped with multiple batteries of palatal 
teeth.  This specimen provides phylogenetically significant information and 
clarifies the distribution of many apomorphies within Choristodera.  
_Philydrosaurus_ is primitive relative to the Neochoristodera in that it 
exhibits only a moderate degree of posterior displacement of the choanae and 
retains a relatively large interpterygoid vacuity.  However, 
_Philydrosaurus_ also exhibits several derived features previously 
considered diagnostic of the Neochoristodera, including establishment of a 
long midline contact of the pterygoids and development of a distinct 
nasopalatal trough extending from the choana.  The choristodere palate 
exhibits significant modification of the primitive diapsid condition, 
including elongation of the vomers, establishment of a vomer-maxilla 
contact, posterior displacement of the choanae, development of the 
nasopalatal trough, and reduction of the interpterygoid vacuity."


Katsura, Y. (2007).  Fusion of sacrals and anatomy in _Champsosaurus_ 
(Diapsida, Choristodera).  Historical Biology 19: 263-271.

Abstract: "Sacral centra are occasionally fused with or without severe 
deformation in _Champsosaurus_ (Diapsida, Choristodera).  The sympatrical 
occurrence of fusion and non-fusion of sacra in adults through their 
evolution questions that sacral fusion represents the final form of a simple 
ontogenetic change or specific variation.  Females are proposed to possess 
more robust limb bones than males because they are considered to have been 
more terrestrial due to the nesting behaviour on land.  The coincidental 
occurrence of fusion of sacral centra without severe deformation and more 
robust limb bones in same individuals suggests that sacral fusion is a 
phenomenon occurring in females as a result of terrestrial adaptation for 
reproductive activities.  Sacral fusion associated with severe deformation 
is considered a pathological condition although its etiology and factors 
remain undefined."

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