Chelotriton sp.

Rage, Jean-Claude & Bailon, Salvador, 2005, Amphibians and squamate reptiles from the late early Miocene (MN 4) of Béon 1 (Montréal-du-Gers, southwestern France), Geodiversitas 27 (3), pp. 413-441 : 415

cf. Chelotriton sp. ( Fig. 1A )

MATERIAL EXAMINED. — 1 incomplete vertebra (Béon 2004 LT 1).

COMMENTS

This opisthocoelous vertebra (centrum length: 3.38 mm) isprovidedwithdivergentand widely separated rib-bearers that are united by a bony lamina up to their lateral tip. Posterior to the prezygapophysis, the anterior zygapophyseal crest dips posteroventrally and it joins the lamina that unites the rib-bearers. Numerous foramina open in the lateral walls of the vertebra. In ventral view, the centrum is c y l i n d r i c a l, p o o r l y d e f i n e d l a t e r a l l y, a n d slightly constricted in the middle of its length. Unfortunately, the neural spine (the morphology of which is characteristic of Chelotriton ) is broken off.

One of the main characteristics of this vertebra is the posteroventral slope of the anterior zygapophyseal crest that joins the lamina connecting the rib-bearers. In salamandrids, this feature occurs in the living Pleurodeles and Tylototriton (but not in Echinotriton , that has been separated from Tylototriton ; N u s s b a u m & B r o d i e 1 9 8 2), a n d i n t h e extinct European genera Chelotriton (middle Eocene-late Pliocene; Bailon 1989) and Brachycormus (late Oligocene and per- haps early Miocene; Estes 1981; Roček 1996). The size and the overall morphology of the available vertebra points to Che- lotriton; however, this single, incomplete specimen cannot permit us to confirm this assignment.

Figures

FIG. 1. — Caudata; A, cf. Chelotriton sp., trunk vertebra (Béon 2004 LT 1); B, Triturus aff. T. helveticus (Razoumowsky, 1789), trunk vertebra (Béon 2004 LT 2); C, Triturus cf. T. marmoratus (Latreille, 1800), trunk vertebra (Béon 2004 LT 5). Dorsal (d), left lateral (l), right lateral (r), and ventral (v) views. Scale bars: 2 mm.