Aquatic ceratopsians and such

[Christopher Taylor <gerarus@westnet.com.au>]

My apologies if these have already been mentioned, Iâve only just rejoined 
the list:

Balanoff, A. M., M. A. Norell, G. Grellet-Tinner & M. R. Lewin. 2008. Digital 
preparation of a probable neoceratopsian preserved within an egg, with comments 
on microstructural anatomy of ornithischian eggshells. _Naturwissenschaften_ 95 
(6): 493-500. (http://dx.doi.org/10.1007/s00114-008-0347-2)

"We describe the first known embryo of a neoceratopsian dinosaur, perhaps the 
most ubiquitous Laurasian group of Cretaceous dinosaurs, which is preserved 
completely enclosed within an egg. This specimen was collected from Late 
Cretaceous beds of southern Mongolia, which commonly preserve fossils of the 
neoceratopsian, Yamaceratops dorngobiensis. The small egg was scanned using 
high-resolution X-ray computed tomography and digitally prepared from the 
matrix. The preserved and imaged elements support a diagnosis of the embryo to 
Neoceratopsia and allow preliminary observations of ontogenetic transformations 
within this group. The addition of an embryo also adds another important data 
point to the already impressive postnatal ontogenetic series that are available 
for this clade."

Li L., Hu D.-Y., Duan Y., Gong E.-P. & Hou L.-H. 2007. Alethoalaornithidae fam. 
nov., a new family of enantiornithine bird from the Lower Cretaceous of western 
Liaoning. _Acta Palaeontologica Sinica_ 46 (3): 365-372. 
(http://www.cqvip.com/qk/90074X/200703/25642898.html) [in Chinese]

"In this paper we report a new family of enantiornithiness from the Early 
Cretaceous of western Liaoning. Alethoalaornithidae Fam. nov. The new family is 
assigned to Cathayornithiformes based on similar length of trochlea at the 
distal end of tarsometatarsus. The main features of Alethoalaornithidae are 
listed belowï sharp beak; few and rudimentary teeth; carpometacarpus 
developed basically ;coracoid broad at the distal end; obvious foramina at the 
proximal end of humerus; long pygostyle; three digits of tarsometatarsus being 
the same in length with trochlea at the same height;and long claws,with no 
curves. The birds of the new family can be compared with enantiornithine birds 
in general morphology. It is important for us to understanding the evolution of 
the enantiornithine birds. Besides, we can infer that the their extinction is 
not only because of the conservative morphological structure itself but also 
the frequent changes of their living environment. Description of new genus
 and species Class Aves Linnaeus, 1758 Subclass Enantiornithes Walker, 1981 
Order Cathayornithiformes Zhou et al., 1992 Family Alethoalaornithidae fam. 
nov. Diagnosis: Long and sharper beak, a few teeth, general two pairs, at last 
three pairs; cervical heterocoelous; furcula process thin and long, its length 
equal to clavicles ramus; sternum carina processes well developed; humerus 
pneumatic foramina well preserved, having deep capital groove; metacarpal 
formed; with rudimentary manual digit claws, small and weak, two only; trochlea 
having same length at the distal end of tarsometatarsus; claw of digit very 
long, and longer than any pedal phalange. Genus Alethoalaornis gen. nov. Type 
species Alethoalaornis agitornis gen. et sp. nov. Etymology ï Alethoï 
Latin, means true; ï-aloï Latin, wing. Diagnosis Same as the family. 
Alethoalaornis agitornis gen. et sp. nov.ïText-fig. 2, figs. 1-5ï Holotype 
LPM ïLiaoning Palaeontologic Museumï 00009, a complete individual ïP I
 ï The specimen stored in Shenyang Normal Un!
iversity.
specimens LPM 00032; LPM 00040 and LPM 00053. Type locality Yuanjiawa, 
Dapingfan, Chaoyang County, western Liaoning. Etymology ï agitoï Latin, 
agile; ï-rnis ï bird suffix. Diagnosis As for the family. Comparison and 
discussion Comparing Alethoalaornis with other early enantiornithines birds 
from western Liaoning, we noticed that the pectoral girdle, coracaid, scapula 
and pelvis of the enantiornithine birds are the same as Enantiornis from the 
Upper Cretaceous of Argentina except the much changed of furcula shape. In 
other words, Enantiornith occurred ranging from Late Jurassic to Early 
Cretaceous, which did not become extinct until Late Cretaceous. The pectoral 
girdle pelvis shape had not beer distinctly changed during several tens of 
million years. These features may be main factors that enantiornithine birds 
could not continue to live in the Cenozoic. Besides ,frequent environment 
changes are also one of important factors. In the irmonograph entitled 
ãStandard Sections of
 Tuchengzi Stage and Yixian Stage and their Stratigraphy, Palaeontology and 
Tectonic- Volcanic Actionsã, Wang Wu-li et al. ï2004ï also investigated 
the relation between fossil organismus and environment, we agree with their 
ecological interpretations of the Late Jurassic to Early Cretaeous in western 
Liaoning-northern Hebei, and that the volcanic activities might have effected 
greatly the occurrence, development and extinction of biotas. They could either 
couse organisms suddenly death, or provide favourable environment for 
organismsï living and developing. The birds of the ïJehol Biotaï would 
have lived and multiplied in such dynamic environment. Stratigraphic horizon 
The lower part of the Jiufotang Formation, Lower Cretaceous."

I'm afraid that anything really informative in this paper appears to be 
concealed in the Chinese section.

Tereschenko, V. S. 2008. Adaptive features of protoceratopoids (Ornithischia: 
Neoceratopsia). _Paleontological Journal_ 42 (3): 273-286.

"The analysis of some morphological characteristics of protoceratopoid 
skeletons, the extent of mobility of the vertebral column, and the probable 
adaptive significance of these features suggest that Bagaceratops had a mostly 
aquatic mode of life, Protoceratops was semiaquatic, Udanoceratops was 
facultatively aquatic, and Leptoceratops was predominantly terrestrial. 
Protoceratopoids were quadrupeds, with the prevalence of hind limbs, probably 
using slow or rapid trotlike gait. An asymmetrical locomotion was most likely 
impossible. On dry land, Bagaceratops and Protoceratops moved slowly. 
Udanoceratops and Leptoceratops approximately equally used rapid and slow 
locomotor modes, although the second could run for a longer time than the 
first."

I don't have access to this last paper, but I wish I did. Anyone out there able 
to send it to me?

    Cheers,

        Christopher Taylor

Christopher Taylor
Dept of Environmental Biology
Curtin University of Technology
GPO Box U1987
Perth
WA 6845
Australia
 
http://catalogue-of-organisms.blogspot.com
 


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