New Papers

["Jerry D. Harris" <jharris@dixie.edu>]

Hi All -

   Some new goodies just emerged:

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   Two newbies from the _Journal of Anatomy_ -- a good, relatively 
high-ranking journal in which we will probably see an increasing number of 
paleo-relevant papers in the future.  Even better, both are available free 
to non-subscribers (via 
http://www.blackwell-synergy.com/toc/joa/208/3;jsessionid=beVVaIWgNPJeU66wLP):

Vickaryous, M.K., and Hall, B.K. 2006. Homology of the reptilian coracoid 
and a reappraisal of the evolution and development of the amniote pectoral 
apparatus. Journal of Anatomy 208(3):263-307. doi: 
10.1111/j.1469-7580.2006.00542.x.

ABSTRACT: As in monotreme mammals, the pectoral apparatus of basal (fossil) 
amniotes includes two coracoid elements, the procoracoid and metacoracoid. 
Among extant reptiles the metacoracoid has long been assumed lost; this 
notion is herein challenged. A comprehensive review of data from numerous 
sources, including the fossil record, experimental embryology, genetic 
manipulations and an analysis of morphology at the level cell condensations, 
supports the conclusion that the metacoracoid gives rise to the majority of 
the reptilian coracoid. By contrast, the reptilian procoracoid remains as a 
rudiment that is incorporated as a process of the (meta)coracoid and/or the 
glenoid region of the scapula early during development, prior to 
skeletogenesis. Application of this integrated approach corroborates and 
enhances previous work describing the evolution of the pectoral apparatus in 
mammals. A revised scenario of amniote coracoid evolution is presented 
emphasizing the importance of considering cell condensations when evaluating 
the homology of a skeletal complex.


Clarke, J.A., Zhou, Z., and Zhang, F. 2006. Insight into the evolution of 
avian flight from a new clade of Early Cretaceous ornithurines from China 
and the morphology of Yixianornis grabaui. Journal of Anatomy 
208(3):287-308. doi: 10.1111/j.1469-7580.2006.00534.x.

ABSTRACT: In studies of the evolution of avian flight there has been a 
singular preoccupation with unravelling its origin. By contrast, the complex 
changes in morphology that occurred between the earliest form of avian 
flapping flight and the emergence of the flight capabilities of extant birds 
remain comparatively little explored. Any such work has been limited by a 
comparative paucity of fossils illuminating bird evolution near the origin 
of the clade of extant (i.e. 'modern') birds (Aves). Here we recognize three 
species from the Early Cretaceous of China as comprising a new lineage of 
basal ornithurine birds. Ornithurae is a clade that includes, approximately, 
comparatively close relatives of crown clade Aves (extant birds) and that 
crown clade. The morphology of the best-preserved specimen from this newly 
recognized Asian diversity, the holotype specimen of Yixianornis grabaui 
Zhou and Zhang 2001, complete with finely preserved wing and tail feather 
impressions, is used to illustrate the new insights offered by recognition 
of this lineage. Hypotheses of avian morphological evolution and 
specifically proposed patterns of change in different avian locomotor 
modules after the origin of flight are impacted by recognition of the new 
lineage. The complete articulated holotype specimen of Yixianornis grabaui, 
from the Early Cretaceous Jiufotang Formation of Liaoning Province, in 
north-eastern China, arguably the best-preserved basal ornithurine specimen 
yet discovered, provides the earliest evidence consistent with the presence 
of extant avian tail feather fanning.

   BTW, to ruin the surprise, the "new lineage" isn't named but includes 
(_Yanornis_ + (_Yixianornis_ + _Songlingornis_)).

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As long as people are talking about _Revista Española de Paleontología_, 
Num. 10 (Extra) has lots of dino papers.  You can view their titles at 
http://sumaris.cbuc.es/cgis/sumari.cgi?issn=02136937&idsumari=A2005N000010V000000[Extra] 
but there are no abstracts or PDFs, or even e-mail addresses for the 
authors.  >>>SIGH<<<

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Lastly, a new paper from _Journal of Morphology_:

Rieppel, O. 2006. 'Type' in morphology and phylogeny. Journal of Morphology 
267(5):528-535. doi: 10.1002/jmor.10424.

ABSTRACT: Comparative morphologists, developmental biologists, as well as 
paleontologists, recognize the existence of 'types,' or 'Baupläne,' in 
nature, marked out by a certain 'sameness' of structure that prevails 
through all variation in shape and function. The 'sameness' that marks out 
'types' is one of structural correspondence (topology and connectivity), 
which is believed to be causally rooted in ontogeny (developmental 
constraints). In an evolutionary context, the structural relations that mark 
out 'types' are explained as relations of homology. The use of concepts such 
as 'type' or 'Bauplan' has been criticized from a 'populational thinking' 
point of view as being incompatible with current evolutionary theory. The 
present article explores the contrasting viewpoints, and concludes that 
current evolutionary theory can accommodate the concept of a 'type' in the 
sense of a 'homeostatic property cluster natural kind.' The 'homeostatic 
property cluster natural kind' is a nonessentialistic concept that allows 
the kind to be historically delimited.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jerry D. Harris
Director of Paleontology
Dixie State College
Science Building
225 South 700 East
St. George, UT  84770   USA
Phone: (435) 652-7758
Fax: (435) 656-4022
E-mail: jharris@dixie.edu
and     dinogami@gmail.com
http://cactus.dixie.edu/jharris/

"Actually, it's a bacteria-run planet, but
mammals are better at public relations."
                                     -- Dave Unwin