[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

New Mesozoic bird stuff (Canada & China)



From: Ben Creisler
bh480@scn.org

A couple of new papers about Mesozoic birds I don't think have been
mentioned on the DML:


Gareth Dyke, Xia Wang, & Gary Kaiser (2011) 
Large fossil birds from a Late Cretaceous marine turbidite sequence on
Hornby Island (British Columbia).
Canadian Journal of Earth Sciences (advance online publication)
doi: 10.1139/e11-050
http://www.nrcresearchpress.com/doi/abs/10.1139/e11-050


Few fossil birds and non-avian dinosaurs are known from Mesozoic sediments
bordering the eastern margin of the Pacific Ocean. Here, we describe
additional remains of Late Cretaceous birds from a deep-water marine
turbidite sequence of the Northumberland Formation exposed on Hornby
Island, British Columbia. The bones described here are referable (based on
hypothesized autapomorphies) to the Cretaceous avian lineages
Enantiornithes and Ornithurae and fall into at least two size classes
within either lineage. This suggests the presence of multiple taxa
occurring within the Northumberland Formation.

===
Barden, H.E., Wogelius, R.A., Li D., Manning, P.L., Edwards, N.P., et al.
(2011)
Morphological and Geochemical Evidence of Eumelanin Preservation in the
Feathers of the Early Cretaceous Bird, Gansus yumenensis. 
PLoS ONE 6(10): e25494. 
doi:10.1371/journal.pone.0025494
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0025494

Recent studies have shown evidence for the preservation of colour in
fossilized soft tissues by imaging melanosomes, melanin pigment containing
organelles. This study combines geochemical analyses with morphological
observations to investigate the preservation of melanosomes and melanin
within feathers of the Early Cretaceous bird, Gansus yumenensis. Scanning
electron microscopy reveals structures concordant with those previously
identified as eumelanosomes within visually dark areas of the feathers but
not in lighter areas or sedimentary matrices. Fourier transform infrared
analyses show different spectra for the feathers and their matrices;
melanic functional groups appear in the feather including carboxylic acid
and ketone groups that are not seen in the matrix. When mapped, the
carboxylic acid group absorption faithfully replicates the visually dark
areas of the feathers. Electron Paramagnetic Resonance spectroscopy of one
specimen demonstrates the presence of organic signals but proved too
insensitive to resolve melanin. Pyrolysis gas chromatography mass
spectrometry shows a similar distribution of aliphatic material within both
feathers that are different from those of their respective matrices. In
combination, these techniques strongly suggest that not only do the
feathers contain endogenous organic material, but that both geochemical and
morphological evidence supports the preservation of original eumelanic
pigment residue.


--------------------------------------------------------------------
myhosting.com - Premium Microsoft® Windows® and Linux web and application
hosting - http://link.myhosting.com/myhosting