Falseryx neervelpensis Szyndlar, Smith & Rage, 2008

Venczel, Márton, Codrea, Vlad A., Solomon, Alexandru A., Fărcaș, Cristina & Bordeianu, Marian, 2025, Late Eocene-early Oligocene snakes from the Transylvanian Basin (Romania), Comptes Rendus Palevol 24 (13), pp. 229-240 : 232

Falseryx neervelpensis Szyndlar, Smith & Rage, 2008

Falseryx cf. neervelpensis

( Fig. 2)

MATERIAL. — Suceag 1: 11 trunk vertebrae ( UBB V 1042 /1-2 ; UBB V 1043 /1-9 ) .

DESCRIPTION

UBB V 1042 /1, is the largest available specimen representing a middle trunk vertebra, lacking its prezygapophyseal areas and the right posterolateral side of its neural arch. In dorsal view, the vertebra appears slightly longer than wide featuring a relatively deep interzygapophyseal constriction, whereas the posterior notch of the neural arch is also deep, bordered by the nearly straight posteromedian margins of the neural arch ( Fig. 2A). The neural spine, representing about one third of the length of the neural arch, is extremely low and widened, and without an anterior or posterior overhang; tiny tubercles are present on its dorsal anterior limit. The anterior margin of the zygosphene is slightly convex, with two protruding lateral lobes (the left one is damaged). In ventral view, the centrum is longer than wide (centrum length (CL) ≈ 3.85 mm; centrum width (CW) ≈ 3.26 mm; CL/CW ≈ 1.18), whereas the haemal keel is prominent, somewhat broadened anteriorly and posteriorly, but tapers near the condylar neck; on the right side a distinct subcotylar tubercle is preserved. The subcentral grooves are indistinct, whereas the subcentral foramina are present; on the right side a distinctly large subcentral foramen is preserved. Only the right paradiapophysis is preserved; it strongly projects laterally and features a well-developed tubercle on the anterior margin of the prezygapophyseal buttress ( Fig. 2B). The surface of the left postzygapophysis preserves numerous lines of arrested growths (LAGs) (for their interpretation, see Venczel et al. 2015), of which six are more discernible, considered as indication of intermittent seasonal growths ( Venczel et al. 2015; Venczel 2023). In lateral view, the haemal keel is prominent and its ventral margin is relatively straight, whereas the subcentral ridges are weakly defined ( Fig. 2C). In anterior view, the roof of the zygosphene is straight with the lateral lobes tilting upward; the cotylar rim is damaged ( Fig. 2D). In posterior view, the neural arch is depressed, slightly convex dorsally and preserves on the left dorsal side of the postzygapophysis a low bony ridge extending anteroposteriorly. No parazygantral foramen is preserved ( Fig. 2E).

The remaining trunk vertebrae are smaller and fragmentary, exhibiting some morphological variation compared to the UBB V 1042 / 1 specimen. The neural spine is consistently low and strongly broadened and with either parallel lateral margins ( Fig. 2F), or distinct posterior widening ( Fig. 2G). Some specimens feature a well-developed median lobe on the zygosphene ( Fig. 2F, G). In the UBB V 1042 / 2 specimen, the paradiapophyses are well-preserved and somewhat differentiated into diapophyseal and parapophyseal portions. The portions of prezygapophyseal buttresses between the paradiapophyses and prezygapophyseal processes, as seen in Falseryx neervelpensis (see Szyndlar et al. 2008), are developed into prominent, anteriorly facing tubercles ( Fig. 2H). In anterior view, the outline of the cotyle appears circular, without paracotylar foramina ( Fig. 2I). In UBB V 1043 /1, representing an anterior trunk vertebra ( Fig. 2J, K), the neural arch appears more vaulted and less elongated, whereas the haemal keel is more prominent and extends posteriorly beyond the condylar neck.

REMARKS

The size and morphology of the above-described vertebrae from Suceag 1 are closely resemble those of Falseryx neervelpensis known from the early Oligocene (MP 21) locality of Boutersem TGV, Belgium. In particular, the prominent tubercles protruding anteriorly on the prezygapophyseal buttresses are highly similar to those observed in this species ( Szyndlar et al. 2008: figs 1, 2). The vertebrae of the type species of the genus (i.e., Falseryx petersbuchi Szyndlar & Rage, 2003 ), known from the Early Miocene (MN 4) localities of Petersbuch 2, Germany and Dolnice, Czech Republic ( Szyndlar & Rage 2003), also bear resemblance to the specimens from Suceag 1. However, they lack the tubercles developed on the prezygapophyseal buttresses, which are considered diagnostic of F. neervelpensis (see Szyndlar et al. 2008).