Pseudopus sp.

Pseudopus sp.

Figure 43 View Fig

Material. Spilia 4: eight trunk vertebrae ( UU SP4 569– UU SP4 571, UU SP4 590, UU SP4 591, UU SP4 627, UU SP4 632, and UU SP4 633), one cloacal vertebra ( UU SP4 584), and 14 caudal vertebrae ( UU SP4 581– UU SP4 583, UU SP4 585– UU SP4 589, UU SP4 634, and UU SP4 635).

Description.

A few trunk vertebrae are present in the sample from Spilia 4 ( Fig. 43 View Fig ). UU SP4 570 is a rather complete trunk vertebra of medium size and with a robustly-built aspect

( Fig. 43f–j View Fig ). Te vertebral centrum is procoelous, dorsoventrally compressed and 5 mm long. Te ventral surface is flat and the lateral margins are oblique and straight in ventral view. In anterior view, the neural canal is roughly as high as the cotyle. Te synapophyses are dorsoventrally elongated. Te zygapophyses are wide, elliptical and dorsally inclined of slightly less than 45°. Te dorsal surface of the neural arch carries a well-developed neural spine, running for the entire length of the arch and ending posteriorly with a slightly expanded area. UU SP4 569 ( Fig. 43a–e View Fig ) and UU SP4 632 are slightly less preserved, but they share with UU SP4 570 both the same morphology and size. UU SP4 571, UU SP4 590, UU SP4 591, and UU SP4 627 are also similar, with the single exception of slightly concave lateral margins in ventral view.

Te morphology of the cloacal vertebra (UU SP4 584) recalls that of the trunk vertebrae ( Fig. 43k, l View Fig ). It has a centrum length of 4 mm.

Te caudal vertebrae from Spilia 4 are robustly built and medium sized ( Fig. 43m –p View Fig ). Tey are procoelous and have a dorsoventrally compressed centrum, provided with fused and narrow haemapophyses on the ventral side. Te latter are not preserved in any of the fossil remains, however, their bases are still visible. Tere is no precondylar constriction and no complete autotomy plane is generally visible. Only few specimens still present an unfused plane on the ventral side of the vertebra. Te caudal vertebrae are provided with wide zygapophyses, which are elliptical and dorsally inclined of slightly less than 45°. Dorsally , there is a laminar neural spine that expands posteriorly. In no case the transverse processes are completely preserved, but a small foramen passing through their bases is visible in at least some of the specimens .

Remarks. Te presence of Pseudopus in the Spilia assemblage is testified by anguid trunk vertebrae with a robust morphological construction, straight and posteriorly convergent lateral margins of the centrum, and neural canal that is not higher than the cotyle in anterior view (Čerňanský et al., 2019; Klembara, 1981). Te caudal vertebrae are attributed to the same taxon because of the similar robustness and the partial or complete fusion of the autotomy plane (Etheridge, 1967; Loréal et al., 2023). A specific attribution of the material is not possible in the absence of cranial elements, but trunk vertebrae with concave margins of the centrum can be recognized as juveniles (Čerňanský et al., 2019; Klembara, 1981).

(non- Anguis ) Anguinae indet.

Figures 44 View Fig , 45 View Fig

Material. Chalicorrema: six osteoderms ( UU RA 421– UU RA 426); Spilia 4: 25 osteoderms ( UU SP4 502, UU

SP4 503, UU SP4 592– UU SP4 602, and UU SP4 647– UU SP4 649) and one caudal vertebra ( UU SP4 705).

Description.

Te osteoderms from Spilia 4 are small- to medium-sized, squared and only moderately robust ( Fig. 44 View Fig ). Tey display a smooth gliding surface, a vermicular sculpturing, and most of them also a low longitudinal keel on the external side.

Te six osteoderms from Chalicorrema are large-sized and robust, with either a subrectangular or subpentagonal shape ( Fig. 45 View Fig ). Te external surface is covered with a vermicular sculpturing except for the smooth surface where the osteoderms were covered by the preceding ones. A low longitudinal keel is visible on at least some of the osteoderms.

UU SP4 705 from Spilia 4 represents only the posterior condyle of a caudal vertebra. Te condyle is dorsoventrally compressed, with no precondylar constriction. Te bases of the fused and narrow haemapophyses are visible.

Remarks. Squared and robust osteoderms, sometimes provided with a keel, are confidently referred to non- Anguis anguine lizards, as osteoderms of the genus Anguis Linnaeus, 1758 , are characterized by an oval or irregular shape and bear no keels (Delfino et al., 2011; Hoffstetter, 1962; Holman, 1998; Klembara & Green, 2010). As such, these osteoderms are evidence of the presence in Chalicorrema and Spilia 4 of a non- Anguis taxon. Accordingly, they could potentially pertain to either the genera Pseudopus described above or Ophisaurus Daudin, 1803 , but in any case, a more precise determination is not possible. Particularly for the case of the osteoderms from Spilia 4, it seems most likely that they pertain to Pseudopus , as that taxon is well documented in that locality by the above-described vertebral material.

As for the fragmentary caudal vertebra UU SP4 705 from Spilia 4, the fused and narrow haemapophyses, the dorsoventral compression, and the absence of a precondylar constriction allow its assignment to an indeterminate anguid, but the very poor preservation hinders any further comment. Tis is also here referred to non- Anguis anguines and most likely to Pseudopus , as this is the only anguid known from that locality.