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Oldest avian eggshell from Japan + other avian papers



Ben Creisler
bcreisler@gmail.com

A number of recent papers:


Takuya Imai & Yoichi Azuma (2014)
The oldest known avian eggshell, Plagioolithus fukuiensis, from the
Lower Cretaceous (upper Barremian) Kitadani Formation, Fukui, Japan.
Historical Biology (advance online publication)
DOI:10.1080/08912963.2014.934232
http://www.tandfonline.com/doi/full/10.1080/08912963.2014.934232#.U8_OePldXTo



Fossil record of Early Cretaceous birds may be geographically biased,
and eggs and eggshells predating the Late Cretaceous were unknown.
Here, we report the oldest known bird eggshell (FPDM-V-0009175)
collected from the upper Barremian Kitadani Formation in Katsuyama
City, Fukui, Japan. The Kitadani Formation likely represents fluvial
environments. Thin-section and scanning electron microscope analyses
revealed diagnostic characters of FPDM-V-0009175, including thin (0.44
mm) shell, smooth external surface, non-branching and narrow pore
canals with relatively constant width, three structural layers,
oblique crystal orientation from vertical in the external layer, and
mammillary to continuous to external layer thickness ratio of
1:1:0.44. These characters allow assignment of FPDM-V-0009175 to a new
oogenus and oospecies, Plagioolithus fukuiensis, and suggest it
belonging to a bird. The three-layered eggshell structure is seen in
extant and extinct birds, Plagioolithus fukuiensis, and non-avian
theropods. Therefore, such structure may be plesiomorphic among
theropods, appearing in the late Barremian or earlier. As the first
bird body fossil from the Mesozoic of Japan, Plagioohlithus fukuiensis
suggests extensive distribution and abundance of birds in the
Barremian East Asia. Plagioolithus fukuiensis indicates that the
late-Barremian birds inhabited and reproduced in the fluvial
environments within a basin located along the eastern margin of the
Asian continent.


http://www.zoobank.org/urn:lsid:zoobank.org:pub:90A8CCE8-57F7-473C-855C-B2CCE2BBD1A2
==


Lucas J. Legendre, Estelle Bourdon, R. Paul Scofield, Alan J. D.
Tennyson, Hayat Lamrous, Armand de Ricqlès and Jorge Cubo (2014)
Bone histology, phylogeny, and palaeognathous birds (Aves: Palaeognathae).
Biological Journal of the Linnean Society 112(4): 688–700)
DOI: 10.1111/bij.12312
http://onlinelibrary.wiley.com/doi/10.1111/bij.12312/abstract

The presence of a phylogenetic signal in the variation of
osteohistological features has been recently debated in the
literature. Previous studies have found a significant signal for some
features, but these results were obtained on a small amount of
characters and a reduced sample. Here we perform a comprehensive study
in which we quantify the phylogenetic signal on 62 osteohistological
features in an exhaustive sample of palaeognathous birds. We used four
different estimators to measure phylogenetic signal – Pagel's lambda,
Abouheif's Cmean, Blomberg's K, and Diniz-Filho's phylogenetic
eigenvector regressions PVR – and four topologies taken from the
literature. Bone size and bone vascular density exhibit a strong
phylogenetic signal, whereas all but four of the remaining features
measured at the histological level – cellular size in caudal and
medial transects of femora, and proportion of oblique vascular canals
in rostral and caudal transects of tibiotarsi – exhibit a weaker
signal. We also found that the impact of the topologies used in the
analyses is very low compared with that of sample size. We conclude
that the analysis of a comprehensive sample is crucial to obtain
reliable quantifications of the phylogenetic signal.

======

Georgina H. Allan, Phillip Cassey, Edward P. Snelling, Shane K.
Maloney and Roger S. Seymour (2014)
Blood flow for bone remodelling correlates with locomotion in living
and extinct birds.
Journal of Experimental Biology (advance online publication)
doi: 10.1242/jeb.102889
http://jeb.biologists.org/content/early/2014/06/03/jeb.102889.abstract


Nutrient arteries enter limb bones through discrete foramina on the
shafts. They are required for bone remodelling in response to
mechanical loading and dynamic forces imposed by locomotion. The
cross-sectional area of the nutrient foramen of the femur represents
an index of blood flow rate to the shaft and thus provides insight
into the animal's level of activity. Morphometric data on femoral
length, mass and foramen size from 100 extant bird species and eight
extinct moa species were analysed allometrically and phylogenetically.
The nutrient foramen blood flow index (Qi) and femur mass (Mf)
increase with body mass (Mb). At 1 kg body mass, cursorial species
have approximately 2.1 times higher Qi and 1.9 times heavier Mf than
volant species. The scaling of Qi on Mf is independent of the primary
mode of locomotion, but the ratio Qi/Mf decreases significantly in
larger birds, although absolute Qi increases. The overall avian
equation for Qi on Mb is not significantly different from previous
data from mammals, but when differences in blood pressure are
accounted for, estimated blood flow to the femur is about 1.9 times
higher in cursorial birds than in mammals, possibly in relation to
bipedalism and quadrupedalism, respectively. Femoral bone blood flow
in both endothermic groups is estimated to be 50-100 times higher than
in ectothermic reptiles.

News story:

http://phys.org/news/2014-07-blood-insights-bird-flight-motion.html