Re: FW: Turtles in the Tree of Life

["David Marjanovic" <david.marjanovic@gmx.at>]

This was evidently supposed to go to the list.

Also, I'm already familiar with the paper, having helped referee it. :-)

----- Original Message -----
From: "Augusto Haro" <augustoharo@gmail.com>
To: "David Marjanovic" <david.marjanovic@gmx.at>
Sent: Thursday, May 14, 2009 7:07 PM
Subject: Fwd: FW: Turtles in the Tree of Life

---------- Forwarded message ----------
From: John Scanlon <riversleigh@outbackatisa.com.au>
Date: 2009/5/13
Subject: FW: Turtles in the Tree of Life
To: VRTPALEO@usc.edu

This will be of interest to many here, I expect; and something else for
David Marjanovic to deal with in his thesis.

The direct link to the paper is
http://www.cnah.org/pdf_files/1217.pdf

-----Original Message-----
From: CNAH [mailto:jcollins@ku.edu]
Sent: 14 May, 2009 12:01 AM
To: undisclosed-recipients:
Subject: Turtles in the Tree of Life

CNAH ANNOUNCEMENT
The Center for North American Herpetology
Lawrence, Kansas
http://www.cnah.org
13 May 2009

TIME OF ORGANOGENESIS SUPPORT BASAL SAUROPSID POSITION OF TURTLES IN THE
AMNIOTE TREE OF LIFE

Ingmar Werneburg & Marcelo R. Sánchez-Villagra

2009. BMC Evolutionary Biology 9:82 (9 pages)

Abstract: The phylogenetic position of turtles is the most disputed aspect 
in the reconstruction of the land vertebrate tree of life. This controversy 
has arisen after many different kinds and revisions of investigations of 
molecular and morphological data. Three main hypotheses of living 
sister-groups of turtles have resulted from them: all reptiles, crocodiles + 
birds or squamates + tuatara. Although embryology has played a major role in 
morphological studies of vertebrate phylogeny, data on developmental timing 
have never been examined to explore and test the alternative phylogenetic 
hypotheses. We conducted a comprehensive study of published and new 
embryological data comprising 15 turtle and eight tetrapod species belonging 
to other taxa, integrating for the first time data on the sideneck turtle 
clade. The timing of events in organogenesis of diverse character complexes 
in all body regions is not uniform across amniotes and can be analysed using 
a parsimony-based method. Changes in the relative timing of particular 
events diagnose many clades of amniotes and include a phylogenetic signal. A 
basal position of turtles to the living saurian clades is clearly supported 
by timing of organogenesis data. The clear signal of a basal position of 
turtles provided by heterochronic data implies significant convergence in 
either molecular, adult morphological or developmental timing characters, as 
only one of the alternative solutions to the phylogenetic conundrum can be 
right. The development of a standard reference series of embryological 
events in amniotes as presented here should enable future improvements and 
expansion of sampling and thus the examination of other hypotheses about 
phylogeny and patterns of the evolution of land vertebrate development.

*****

A gratis PDF of this article is available from the CNAH PDF Library at

http://www.cnah.org/cnah_pdf.asp