Paralatonia transylvanica, Venczel & Csiki, 2003

Venczel, Márton & Csiki, andZOLTÁN, 2003, New frogs from the latest Cretaceous of Hateg Basin, Romania., Acta Palaeontologica Polonica 48 (4), pp. 609-616 : 612-614

publication ID	https://doi.org/ 10.5281/zenodo.13394058
persistent identifier	https://treatment.plazi.org/id/436E87E6-BB0C-FFFD-FFE2-08B2FAFCF9E9
treatment provided by	Felipe
scientific name	Paralatonia transylvanica
status	sp. nov.

Treatment

Paralatonia transylvanica sp. nov.

Eodiscoglossus sp. ; Grigorescu et al. 1999: 305–308, fig. 3: 3–11.

Etymology: After “ Transsylvania ”, Latin, geographic name of Transylvania, Romania.

Holotype: FGGUB v. 455, partial left ilium missing most of iliac shaft and supraacetabular expansion ( Figs. 1B View Fig , 3A View Fig ).

Holotype locality, horizon, and age: Vălioara−Budurone microvertebrate locality, about 4 km west of the village Vălioara , Haţeg Basin , Romania; middle member of the Densuş−Ciula Formation ( Grigorescu et al. 1999). The sedimentological development indicates the presence of a braided−meandering river system and channels; the microvertebrate bearing sediments are grey−bluish to blackish mudstones of Maastrichtian age (Grigorescu and Csiki 2002).

Referred specimens: FGGUB v. 446 ( Fig. 5D View Fig ), v. 447 ( Fig. 5B View Fig ), v. 448 ( Fig. 5C View Fig ), v. 402, v. 461, v. 462, partial maxillae; FGGUB v. 449 ( Fig. 4E View Fig ), v. 450 ( Fig. 4D View Fig ), v. 403, v. 404, v. 405, partial prearticulars; FGGUB v. 442 ( Fig. 6E View Fig ), v. 443 ( Fig. 6F View Fig ), partial scapulae; FGGUB v. 410 ( Fig.3 View Fig ), v. 439 ( Fig.3D View Fig ), v. 452 ( Fig.3E View Fig ), v. 409, v. 411, partial ilia.

Distribution.—Latest Cretaceous (Maastrichtian), Romania.

Diagnosis.—A small d iscoglossid frog having an inferred snout−vent length of about 40–50 mm. The ilium of Paralatonia differs from Hatzegobatrachus , as well as from Alytinae, Bombinatorinae, and Gobiatinae discoglossids in having prominent iliac crest. Differs from Callobatrachus and Enneabatrachus in having a higher iliac crest. Differs from Discoglossus in having a smaller preacetabular process. Differs from Eodiscoglossus in having a more expanded acetabular rim and by presence of an iliac synchondrosis. Differs from Latoglossus and Latonia in having a comparatively smaller inferred body size and by lack of waisting between the acetabular region andiliac shaft. Differs from Paradiscoglossus in having shallower supraacetabular fossa anda more expandedacetabular rim. Differs from Wealdenbatrachus in the lack of waisting between the acetabular region andthe iliac shaft, andin having smaller iliac synchondrosis.

Description.—The holotype specimen preserves the acetabular region andthe base of iliac shaft ( Figs. 1B View Fig , 3A View Fig ). The supra − acetabular region is relatively wide, with the supraacetabular expansion orientedposterodorsally. The latter structure is bro − ken off, but was strongly developed extending to the dorsal limit of the ischium. The subacetabular region is relatively small, with a short subacetabular expansion. On the medial side of the latter there is an area not coveredby periosteum. The acetabular fossa is nearly circular with a posteriorly widened acetabular rim. The latter is prominent anteroventrally andprojects beyond the ventral margin of the bone. Dorsally the acetabular rim is nearly imperceptible, but near the posterodorsal margin of the acetabular region it is raisedagain delimiting a rather shallow supraacetabular fossa. In the vicinity of the anteroventral margin a small preacetabular fossa is observed. The posterior border of the acetabular fossa is broken off. In posterior view the ilioischiadic junction displays the typical discoglossid pattern, being distinctly widened ventrally. In lateral view there is a relatively high dorsal crest. The dorsal protuberance, formed by the thickened posterodorsal margin of the dorsal crest, is elongated andmoderately prominent. Ventrally to the latter there is a shallow fossette (= dorsal protuberance’s fossette).

bly of moderate height ( Fig. 5C View Fig ), with a distinct palatine process ( Fig. 5D View Fig ), anda somewhat raisedzygomaticomaxillaris process ( Fig. 5B, C View Fig ). The horizontal lamina is rather wide and with a convex lingual surface. The tooth row extends posteriorly to the base of the pterygoidprocess. The tip of the latter structure is not preserved. There is a deep posterior depression ( Fig. 5B, C View Fig ).

Prearticular ( Fig. 4D View Fig 1 View Fig , D 2 View Fig , E 1 View Fig , E 2 View Fig ). —The specimens belonged to various sized individuals. In all the specimens the dorsal surface of the coronoid process is concave and projects lingually, with the lingual margin slightly bent dorsally. The paracoronoidcrest is better developedposteriorly. Meckel’s groove is well markedandis slightly constrictedat the level of the coronoidprocess. In specimen FGGUB V. 403 (see Grigorescu et al. 1999: fig. 3: 4), a moderately wide, deep spatulate extremity is preserved. The labial surface above the external mandibular crest is concave, the latter structure ending posteriorly in a small tubercle.

Scapula ( Fig. 6E, F View Fig ).—The bone is relatively short andcleft, with a deeply concave posterior margin. The acromial part of scapula projects well beyond the glenoid margin.

paracoronoid crest Meckel’s groove

Maxilla ( Fig. 5B–D View Fig ).—All the available specimens are fragmentary, preserving various parts of the maxilla. The labial surface is smooth without secondary bony ornament; there are few small nutritive foramina. The facial part of maxilla was probaIlium ( Fig. 3C–E View Fig ).—Part of the material was already described under the generic name Eodiscoglossus ( Grigorescu et al. 1999: fig. 3: 7–11). The FGGUB v. 439 ( Fig. 3D View Fig ), representing a partial right ilium, preserves a relatively large supraacetabular expansion, projecting posterodorsally. The supraacetabular fossa is rather shallow and extends parallel to the dorsal acetabular rim. The dorsal protuberance is elongatedandbarely swollen along the posterodorsal margin of the iliac shaft. In FGGUB v. 452 ( Fig. 3E View Fig ), the acetabular rim is prominent anteriorly andthere is a small preacetabular fossa. The dorsolateral surface of the iliac shaft shows clear signs of anomaly. Laterally there are several grooves andpits, while part of the muscular insertion surface on the dorsal protuberance is shifted medially. FGGUB V.410 ( Fig. 3C View Fig ), figuredin Grigorescu et al. 1999 (fig. 3: 9–11), preserves a right iliac shaft provided with a moderately high andstrongly medially inclineddorsal crest.

Remarks.—The ilium in Paralatonia shows a combination of derivedfeatures (well−developedandstrongly medially bent dorsal crest, crest−like dorsal protuberance, anteroventrally expandedacetabular rim, andsmall interiliac synchondrosis), that morphologically approaches the condition seen in Latonia ( Fig. 3B View Fig ). In posterior view, the shape of ilioischiadic junction of Paralatonia closely resembles that of Discoglossus and Latonia ( Hodrova 1987: text−fig. 1: 6; Bailon 1999: pl. 19A).

The coronoidprocess of prearticular in Paralatonia is more derived than that of Eodiscoglossus , approaching the condition seen in Discoglossus , in which the coronoidprocess is elongatedandhas a concave surface (see Bailon 1999: pl.

9A). In Latoglossus the coronoidprocess has a nearly flat dor − sal surface andforms a rather thick sub−rectangular lamina ( Hossini 2000: fig. 1A, B). To the contrary, the prearticular in Latonia is providedwith two coronoidprocesses ( Hodrova 1987; Roček 1994).

The maxilla lacks a labial sculpture, condition similar to other discoglossids, except some members of Latonia (e.g., Latoniagigantea) and Gobiates (Špinar andTatarinov 1986). The well−developed pterygoidal process of maxilla, as well as the presence of a posterior depression and a relatively high zygomaticomaxillaris process is reminiscent of Discoglossus , Latoglossus and Latonia (see Bailon 1999: pl. 2G–I; Hossini 2000: fig. 1C, D; Roček 1994: fig. 9). In the maxilla of Eodiscoglossus there is no prominent pterygoidal process, andthe posterior depression is lacking ( Evans et al. 1990; Sanchíz 1998: fig. 39D).

The scapula assignedto Paralatonia is short andcleft, similarly to most members of Discoglossidae . According to Borsuk−Białynicka andEvans (2002), the cleft scapula of many primitive anurans (including Prosalirus , Notobatrachus , some Leiopelma , and Eodiscoglossusoxoniensis) represents the basal anuran condition. In Wealdenbatrachus , contrary to other discoglossine frogs, there is a long Leiopelma − like scapula ( Sanchíz 1998).

Considering all the above features, Paralatonia appears as a transitional form between primitive ( Eodiscoglossus −like) and more derived discoglossids (e.g., Latonia ).