Lissotriton sp.

Fig. 4

Material.

Six vertebrae, HLMD-Ez 2047-2050.

Description.

The preserved small-sized trunk vertebrae have opistocoelous centra measuring up to 2 mm in length. The condyle is shorter and slightly smaller than the cotyle. The pericondylar constriction is well pronounced. The anteriorly oriented prezygapophyses have an oval outline. In dorsal view, the neural arch has a weakly-pronounced sandglass shape, where the narrowest part is located behind the prezygapophyses. The posterior margin of the neural arch is either flat or slightly bifurcated. The posterior notch is well preserved and visible on HLMD-Ez 2047 (Fig. 4E). The neural spine starts behind the anterior margin of the neural arch and reaches the posterior tip of the latter (Fig. 4B, G). The neural spine is always missing; however, where it is preserved, no ornamentation can be observed on it, and its rather large height can be suggested. The pre- and postzygapophyses are connected by a well-pronounced (nearly) horizontal interzygapophyseal crest, which covers slightly the proximal part of the transverse process (Fig. 4B). The transverse process is composed of the dia- and parapophysis, which in turn are connected by an osseous lamina along their length. In ventral view, the anterior and poster processes form a distinct ventral lamina of triangular to irregular rhomboidal shape (Fig. 4C, H). It is pierced by two smaller subcentral foramina near the center of the vertebra centrum. The anterior alar process is larger than the posterior one. The opening of the spinal nerve is visible behind the transverse process at the base of the neural arch. In anterior view, the neural canal is large (larger than the diameter of the condyle) and has a round or slightly expressed pentagonal outline (Fig. 4D, I). In posterior view, the neural canal is also large and has a round or slightly elliptical outline (Fig. 4E, J).

Remarks.

The remains can be clearly assigned to the genus Lissotriton considering their small sizes; the lack of the dorsal widening or any structures on the neural spine; the presence of a well-pronounced rhomboid/triangular ventral lamina on the vertebral centrum (Ivanov 2008; Georgalis et al. 2019). On the one hand, poor and partial preservation of vertebrae and, on the other hand, not adequate knowledge of the osteology of the Lissotriton genus does not allow any further allocation at species or species group levels.

Salamandra Garsault et al., 1764