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Re: FW: Turtles in the Tree of Life

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

-----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

The Center for North American Herpetology
Lawrence, Kansas
13 May 2009


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