New Acta Palaeontologica Polonica issue: Archaeopteryx shoulders and Oligocene Passeriformes

[gerarus@westnet.com.au]

The new edition of Acta Palaeontologica Polonica has just appeared,
and as well as some very interesting looking stuff on Lower Cambrian
fossils (Cambrian thylacocephalans! Basal lobopods! Hyolithelminths
and chancelloriids!) it also includes the following:

Senter, P. 2006. Scapular orientation in theropods and basal birds,
and the origin of flapping flight. Acta Palaeontologica Polonica
51(2): 305-313.
"Basal birds such as Archaeopteryx  and Confuciusornis are typically
portrayed as flapping fliers. However, here I show that shoulder
joint orientation in these animals prevented elevation of the humerus
above the dorsum, thereby preventing use of the recovery stroke, an
important part of flapping flight. In members of the clade
Ornithothoraces, which includes extant birds and the extinct avian
clade Enantiornithes, the shoulder joint is reoriented to permit
elevation of the humerus above the dorsum, permitting flapping
flight. Although basal birds may have glided, flapping flight began
significantly later in avian evolution than has been thought."

Also, the Oligocene European basal passeriform of Mayr and Manegold
(2004) has received a name and a better description:

Mayr, G., & A. Manegold. 2006.  New specimens of the earliest
European passeriform bird. Acta Palaeontologica Polonica 51 (2):
315-323.
"We describe new specimens of the oldest European passeriform bird
from the early Oligocene of Germany. This bird has hitherto been
known only from a poorly preserved skeleton and we report here a
second slab of the same specimen and an additional fragmentary skull.
The new specimens allow the description of a new species, Wieslochia
weissi gen. et. sp. nov., which lacks apomorphies of crown group
Oscines, the taxon including most extant and all European passeriform
species. In overall osteology, Wieslochia  most closely resembles
extant Suboscines but these similarities may be plesiomorphic for
Passeriformes. W. weissi differs from the stem species pattern
hypothesized for Eupasseres in the morphology of the distal
carpometacarpus, the absence of a hooked processus acrocoracoideus
(coracoid), and the presence of furrows instead of certain canals on
the hypotarsus, and may even be outside crown group Eupasseres, the
clade including Oscines and Suboscines. Because the earliest European
fossil record of oscine passerines is from the late Oligocene,
passerines outside crown group Oscines may have colonized Europe
before the arrival of Oscines from the Australian continental plate."

    To deconstruct: _Wieslochia_ is "suboscine-grade", but not enough
characters are preserved or free from homoplasy to suggest a more
specific position in Passeriformes other than definitely not Oscines.
Funnily enough, a number of characters are apparently shared with
_Phytotoma_, but as the latter is a derived cotingid, I hardly think
it's a likely option for closest relative.

    Cheers,

        Christopher Taylor