Latonia gigantea (Lartet, 1851)

Venczel, Márton & Stiuc, Emanoil, 2008, Late middle Miocene amphibians and squamate reptiles from Taut ,, Romania, Geodiversitas 30 (4), pp. 731-763 : 741-744

publication ID	https://doi.org/ 10.5281/zenodo.4665621
persistent identifier	https://treatment.plazi.org/id/03D08790-FFCF-FFE5-57F5-A225FB175595
treatment provided by	Felipe
scientific name	Latonia gigantea (Lartet, 1851)
status

Treatment

MATERIAL EXAMINED. —Two premaxillae ( ISER Tt-0370/1 and 2), eight maxillae ( ISER Tt-0371/1-8), five frontoparietals ( ISER Tt-0372/1-5), one presacral vertebra ( ISER Tt-0373), one coracoid ( ISER Tt-0374), one humerus ( ISER Tt-0375), two ilia ( ISER Tt-0376/1 and 2).

DESCRIPTION

Premaxilla

The anterior surface of the premaxilla is smooth ( Fig. 6B View FIG , B’). The alary process is relatively wide and convex dorsally. The palatine process is well developed; there are 18 tooth positions preserved

on the premaxilla.

Late middle Miocene amphibians and reptiles from Taut,, Romania

Frontoparietal

The best preserved specimen, representing a posterior half of a frontoparietal, belonged to a relatively large sized individual ( Fig. 6A View FIG , A’). The dorsal surface is broad and covered by a dense secondary sculpture; the tubercules tend to form rows near the posterior and lateral margins. The ventral surface exhibits the posterior part of frontoparietal incrassation, which is roughly circular. The latter structure is bordered laterally by prominent bony laminae diverging posteriorly, which represents the pars contacta ( Roček 1994).

Maxilla

Most specimens are fragmentary and represent different maxillary parts ( Fig. 6 View FIG C-F’). The processus zygomaticomaxillaris was presumably rather high as suggested by ISER Tt-0371/1( Fig.6C View FIG ,C’).The labial surface is covered by secondary sculpture formed by prominent tubercles which stay dispersed or usually constitute confluent rows. The extent of labial sculpture displays a wide ontogenetic variation. In smaller (i.e. younger) individuals the sculpture covers only the posterior maxillary region as seen in ISER Tt-0371/2 ( Fig. 6F View FIG , F’), but in larger (i.e. older) specimens it usually reaches the level of the palatine process. The pterygoid process is prominent and projects posteromedially.The posterior depression is usually shallow and limited anteriorly by a transversal bony ridge at the level of the pterygoid process. The horizontal lamina is rather wide and convex lingually. The tooth row extends posteriorly to the level of the pterygoid process, but in some specimens (e.g. ISER Tt-0371/3) is just finished at that level ( Fig. 6E View FIG ).

Presacral vertebra

The only available specimen(ISER Tt-0373) is opisthocoelous and provided with well-developed interzygapophyseal ridges and a low neural ridge ( Fig. 7A View FIG , A’). However, a distortion is observed: the neural ridge is shifted rightwards,while the right postzygapophysis is positioned more anteriorly with its long axis oriented more laterally than that of the left side.

Coracoid

In the only available fragmentary specimen, the shaft

is slightly curved and provided with a low ridge on

Venczel M. & Ştiucă E.

views; C, E’, right lateral views; C’, D, E, F, medial views; D’, F’, left lateral views. Scale bar: 2 mm.

Late middle Miocene amphibians and reptiles from Taut,, Romania

Tt-0374); D, ilium (ISER Tt-0376/1); A, B, dorsal views; A’, B’, C, ventral views; D, right lateral view. Scale bar: 2 mm. Venczel M. & Ştiucă E.

its posterior surface ( Fig. 7C View FIG ). The pars glenoidalis is strongly dilated with a rounded shape.

Humerus

ISER Tt-0375 represents the fragmentary distal shaft of a humerus which belonged to an extremely large individual ( Fig. 7B View FIG , B’). The distal humeral ball is rounded and is slightly shifted laterally; the

medial epicondyle is rather prominent. Ilium

ISER Tt-0376 lacks the supraacetabular region and most part of preacetabular region ( Fig. 7D View FIG ). A small preacetabular fossa is present. The tuber superior is well defined without a lateral projection. The iliac crest was rather high.

REMARKS

The material of L. gigantea recovered from Tauţ, mostly consisting of skull bones, belonged almost exclusively to specimens of relatively large size. These remains are easily distinguishable from L. ragei Hossini, 1993 , another large discoglossid within the stratigraphic range of L. gigantea ( Böhme & Ilg 2003) , because despite its similarly large size lacks a secondary sculpture. In L. seyfriedi Meyer, 1843 , known from the late middle Miocene (MN 8) of Oehningen ( Germany) only( Roček 1994), the holotype and all the referred specimens are imbedded in the sediment by their dorsal side. Consequently it is not known if its skull bones bear or not a secondary sculpture. However, if the latter character would be present in L. seyfriedi , then L. gigantea will become a junior synonym of the former. Thus, only further investigation of the type material would answer this taxonomic problem.

Family PALAEOBATRACHIDAE Cope, 1865