Tuesday, July 26, 2016

[Paleontology • 2016] Phosphotriton sigei • Synchrotron Analysis of A ‘Mummified’ Salamander (Vertebrata: Caudata) from the Eocene of Quercy, France


Figure 4. Three-dimensional reconstruction of the skeleton of Phosphotriton sigei gen. et sp. nov. (B), scaled to the same length as other Eurasian urodeles: a European plethodontid, Hydromantes italicus Dunn, 1923 (A), and two salamandrids, Hypselotriton orientalis (David, 1873) (C) and Salamandra salamandra (Linnaeus, 1758) (D).   

Abstract
An incomplete ‘mummy’ from the Phosphorites du Quercy (presumed Eocene) was identified as a salamander during the 19th century. The specimen has now been computed tomography (CT) scanned, and this revealed the incomplete skeleton (with perfectly preserved bones) and soft tissues (lung). The fossil represents a new, well-characterized taxon. Despite the absence of the skull, several features allow a phylogenetic analysis. The fossil belongs to pseudosaurian caudates; it is tentatively assigned to the Salamandridae, although affinities with Plethodontidae cannot be definitely ruled out.

Keywords: exceptional preservation; Lissamphibia; Phosphorites du Quercy; phylogeny; Salamandridae; skeleton; tomography; Urodela


Systematic Paleontology

Caudata Fischer von Waldheim, 1813
Pseudosauria Blainville, 1816
?Treptobranchia Frost, Grant, Faivovich et al., 2006
?Salamandridae Goldfuss, 1820

Phosphotriton gen. nov.

Etymology: Greek ϕωσϕόροςphosphorus, in reference to the nature of the sediment; triton, a frequent suffix in the genus names of salamanders.

Phosphotriton sigei sp. nov.

Holotype: An incomplete ‘mummified’ body of a salamander (MNHN.F.QU17755).


Diagnosis: A non-elongate, lunged caudate amphibian referred to Pseudosauria, based on the presence of a median process on the ischium, clearly separated para- and diapophyses on trunk vertebrae, spinal nerves exiting intravertebrally in caudal vertebrae, and in lacking articulated ribs in the caudal region. Tentatively referred to Salamandridae on the basis of having a paired sacral rib, a median notch in the posterior border of the neural arch, neural spines low on trunk vertebrae, neural spines present on caudal vertebrae, a bony lamina connecting para- and diapophyses, and spinal nerves exiting intravertebrally in posterior trunk vertebrae. Differs from other Pseudosauria by the presence of an anterior interzygapophyseal ridge, a dorsal alar process extending between the parapophysis and prezygapophysis and amphicoely of centrum, an association of characters that is unique within the clade.



Figure 4. Three-dimensional reconstruction of the skeleton of Phosphotriton sigei gen. et sp. nov. (B),
scaled to the same length as other Eurasian urodeles: a European plethodontid, Hydromantes italicus Dunn, 1923 (A), and two salamandrids, Hypselotriton orientalis (David, 1873) (C) and Salamandra salamandra (Linnaeus, 1758) (D).

Type locality: Unknown locality of the Phosphorites du Quercy, south-western France.
Horizon: Likely Eocene (late Middle or Late Eocene).

Etymology: After Bernard Sigé, one of the main contributors of the Quercy campaigns.

......

Jérémy Tissier, Jean-Claude Rage, Renaud Boistel, Vincent Fernandez, Nicolas Pollet, Géraldine Garcia andMichel Laurin. 2015. Synchrotron Analysis of A ‘Mummified’ Salamander (Vertebrata: Caudata) from the Eocene of Quercy, France. Zoological Journal of the Linnean Society. 177(1); 147–164.   DOI:   10.1111/zoj.12341


No comments:

Post a Comment