Tag Archives: Turtles

A Middle Triassic stem-turtle and the evolution of the turtle body plan

A new stem-turtle, Pappochelys rosinae, is structurally and chronologically intermediate between the stem-turtles Eunotosaurus and Odontochelys and is from the late Middle Triassic of Germany (Ladinian; ∼240 million years ago). The three taxa share anteroposteriorly broad trunk ribs that are T-shaped in cross-section and bear sculpturing, elongate dorsal vertebrae, and modified limb girdles. Pappochelys closely resembles Odontochelys in various features of the limb girdles. Unlike Odontochelys, it has a cuirass of robust paired gastralia in place of a plastron. Pappochelys provides new evidence that the plastron partly formed through serial fusion of gastralia. The skull of Pappochelys has small upper and ventrally open lower temporal fenestrae, supporting the hypothesis of diapsid affinities of turtles.


Life reconstruction:


JEZ Special Issue on Turtle Origins and Evolution, freely available

Dear colleagues:

The new Journal of Experimental Zoology Part B: Molecular and Developmental Evolution 324(3): 169–314 is a Special Issue on Turtle Origins and Evolution that I have edited.

This issue is inspired by a symposium that was held at the 10th International Congress of Vertebrate Morphology, and many participants from that symposium have contributed papers here. All articles are “Freely Available” for the next three months.


The dawn of chelonian research: Turtles between comparative anatomy and embryology in the 19th century (pages 169–180)
Kate MacCord, Guido Caniglia, Jacqueline E. Moustakas-Verho and Ann C. Burke
DOI: 10.1002/jez.b.22587

The origin of turtles: A paleontological perspective (pages 181–193)
Walter G. Joyce
DOI: 10.1002/jez.b.22609

The evolutionary origin of the turtle shell and its dependence on the axial arrest of the embryonic rib cage (pages 194–207)
Tatsuya Hirasawa, Juan Pascual-Anaya, Naoki Kamezaki, Mari Taniguchi, Kanako Mine and Shigeru Kuratani
DOI: 10.1002/jez.b.22579

Emerging from the rib: Resolving the turtle controversies (pages 208–220)
Ritva Rice, Paul Riccio, Scott F. Gilbert and Judith Cebra-Thomas
DOI: 10.1002/jez.b.22600

The integumental appendages of the turtle shell: An evo-devo perspective (pages 221–229)
Jacqueline E. Moustakas-Verho and Gennadii O. Cherepanov
DOI: 10.1002/jez.b.22619

Modeling neck mobility in fossil turtles (pages 230–243)
Ingmar Werneburg, Juliane K. Hinz, Michaela Gumpenberger, Virginie Volpato, Nikolay Natchev and Walter G. Joyce
DOI: 10.1002/jez.b.22557

On the homology of the shoulder girdle in turtles (pages 244–254)
Hiroshi Nagashima, Fumiaki Sugahara, Masaki Takechi, Noboru Sato and Shigeru Kuratani
DOI: 10.1002/jez.b.22584

A comparative examination of odontogenic gene expression in both toothed and toothless amniotes (pages 255–269)
Alexis J. Lainoff, Jacqueline E. Moustakas-Verho, Diane Hu, Aki Kallonen, Ralph S. Marcucio and Leslea J. Hlusko
DOI: 10.1002/jez.b.22594

Do turtles follow the rules? Latitudinal gradients in species richness, body size, and geographic range area of the world’s turtles (pages 270–294)
Kenneth D. Angielczyk, Robert W. Burroughs and Chris. R. Feldman
DOI: 10.1002/jez.b.22602

Loggerhead sea turtle environmental sex determination: Implications of moisture and temperature for climate change based predictions for species survival (pages 295–314)
Jeanette Wyneken and Alexandra Lolavar
DOI: 10.1002/jez.b.22620
Wiley has published a version of this article without corrections following review, and we are currently waiting for them to publish the finished article as an erratum.


Evolutionary origin of turtle shell

Tyler R. Lyson, Gabe S. Bever, Torsten M. Scheyer, Allison Y. Hsiang & Jacques

A. Gauthier (2013) Evolutionary Origin of the Turtle Shell.
Current Biology (advance online publication)
doi: http://dx.doi.org/10.1016/j.cub.2013.05.003

The origin of the turtle shell has perplexed biologists for more than two
centuries. It was not until Odontochelys semitestacea was discovered,
however, that the fossil and developmental data could be synthesized into
a model of shell assembly that makes predictions for the as-yet
unestablished history of the turtle stem group. We build on this model by
integrating novel data for Eunotosaurus africanus-a Late Guadalupian
(~260 mya) Permian reptile inferred to be an early stem turtle. Eunotosaurus
expresses a number of relevant characters, including a reduced number of
elongate trunk vertebrae (nine), nine pairs of T-shaped ribs, inferred loss of
intercostal muscles, reorganization of respiratory muscles to the ventral side
of the ribs, (sub)dermal outgrowth of bone from the developing perichondral
collar of the ribs, and paired gastralia that lack both lateral and median elements.
These features conform to the predicted sequence of character acquisition
and provide further support that E. africanus, O. semitestacea, and
Proganochelys quenstedti represent successive divergences from the turtle
stem lineage. The initial transformations of the model thus occurred by the Middle
Permian, which is congruent with molecular-based divergence estimates for the
lineage, and remain viable whether turtles originated inside or outside crown Diapsida.

Latest attempt on turtle affinities…

… although without fossils this time.

A Phylogenomic Approach to Vertebrate Phylogeny Supports a Turtle-Archosaur Affinity and a Possible Paraphyletic Lissamphibia

Fong JJ, Brown JM, Fujita MK, Boussau B

PLoS ONE 7(11): e48990. doi:10.1371/journal.pone.0048990

In resolving the vertebrate tree of life, two fundamental questions remain: 1) what is the phylogenetic position of turtles within amniotes, and 2) what are the relationships between the three major lissamphibian (extant amphibian) groups? These relationships have historically been difficult to resolve, with five different hypotheses proposed for turtle placement, and four proposed branching patterns within Lissamphibia. We compiled a large cDNA/EST dataset for vertebrates (75 genes for 129 taxa) to address these outstanding questions. Gene-specific phylogenetic analyses revealed a great deal of variation in preferred topology, resulting in topologically ambiguous conclusions from the combined dataset. Due to consistent preferences for the same divergent topologies across genes, we suspected systematic phylogenetic error as a cause of some variation. Accordingly, we developed and tested a novel statistical method that identifies sites that have a high probability of containing biased signal for a specific phylogenetic relationship. After removing putatively biased sites, support emerged for a sister relationship between turtles and either crocodilians or archosaurs, as well as for a caecilian- salamander sister relationship within Lissamphibia, with Lissamphibia potentially paraphyletic.



Carbonemys cofrinii

This is what happens when you don’t subscribe to Journal of Systematic Paleontology and you don’t check in with twitter!

“New pelomedusoid turtles from the late Palaeocene Cerrejon Formation of Colombia and their implications for phylogeny and body size evolution”

Authors: Edwin Cadena, Dan Ksepka, North Carolina State University; Carlos Jaramillo, Smithsonian Tropical Research Institute, Panama; Jonathan Bloch, Florida Museum of Natural History

Published: In the Journal of Systematic Palaeontology



Kurtén Club 30.11.

Dear all,

next Tuesday, Jaqcueline Moustakas will give a talk (a practice for the SICB meeting) about

How the Turtle Got its Spots.

Time & Loc.:
16.00, 30.11.2010, C108 Physicum