Palaeovaranus sp.

Palaeovaranus sp.

Figures 20 View Fig , 21 View Fig , 22 View Fig

Material. One left maxilla ( UM-BFI 3055); one trunk vertebra ( UM-BFI 3131); and eight caudal vertebrae ( UM-BFI 3133, UM-BFI 3138, UM-BFI 3140, UM-BFI 3149, UM-BFI 3184, UM-BFI 3195, UM-BFI 3199, and UM-BFI 3203).

Description

Maxilla: UM-BFI 3055 is a left maxilla missing most of its posterior medial portions ( Fig. 20a–c View Fig ). Te two preserved teeth have a mesiodistally broad base, and their shafts are curved posteriorly ( Fig. 19a View Fig ). Plicidentine folds are well developed ( Fig. 20a View Fig ). Te nasal process gradually increases in height posteriorly ( Fig. 20a View Fig ). Te supradental shelf is thin and projects lingually ( Fig. 19a View Fig ). Anterodorsal to the supradental shelf, the basal torus ( Georgalis et al., 2021a) is visible medially ( Fig. 20a, b View Fig ). Posterior to the basal torus, the anterior region of the lacrimal recess is shallow and pierced by an open foramen ( Fig. 20b View Fig ). Tere seems to be an articulation facet, perhaps for the vomer (“oblique internasal lamella” in Georgalis et al., 2021a, 2021b, 2021c; this feature could be taxonomically informative, but a broader comparison to maxillae of other anguimorphs is needed). Te labial surface of the maxilla is pierced by two labial foramina, approximately at the level of the supradental shelf ( Fig. 20c View Fig ).

Trunk vertebra: Te single available trunk vertebra (UM-BFI 3131) is rather large (7 mm centrum length). Te centrum is procoelous, longer than the neural arch and widens anteriorly ( Fig. 21 View Fig ). Te cotyle is very depressed ( Fig. 21a View Fig ). Te neural arch is slightly vaulted, and the neural spine is broken near its base ( Fig. 21e View Fig ). Te ventral surface of the centrum bears two distinct ridges ( Fig. 21d View Fig ).

Caudal vertebrae: Te description is based on the best-preserved vertebra, UM-BFI 3133, as the other six are rather incomplete ( Fig. 22 View Fig ). Te vertebra is very elongated anteroposteriorly and slender ( Fig. 22c, d, e View Fig ). Te cotyle is not depressed and is wider than tall ( Fig. 22a View Fig ). Te prezygapophyses are strongly inclined dorsomedially, with an articular facet extending dorsolaterally

( Fig. 22a, c View Fig ). Te neural spine is tall and found at the posterior end of the neural arch only ( Fig. 22c, e View Fig ). However, it does extend up to the anterior margin of the neural arch as a thin and low neural ridge ( Fig. 22c View Fig ). No autotomic septum is present ( Fig. 22d View Fig ). On the ventral surface of the centrum, an hourglass-shaped groove extends medially on the entire length of the centrum, flanked by two lateral ridges ( Fig. 22d View Fig ). On the posterior margin of the ventral surface, two thick pedicellate facets for the chevrons are visible ( Fig. 22d View Fig ).

Attribution and remarks. Te dentition, consisting of large, subpleurodont, curved teeth is reminiscent of three large lizards from the Eocene of the Quercy, Eurheloderma , Palaeovaranus , and Saniwa (see Augé, 2005; Georgalis & Scheyer, 2019; Georgalis et al., 2021a; Čerňanský et al., 2024). Two of them, Eurheloderma and Palaeovaranus , have been mentioned from this locality ( Augé, 2005; Georgalis et al., 2021a). In Palaeovaranus , the nasal process moderately increases in height posteriorly and bears a distinctly developed nasal crest on its dorsomedial surface ( Georgalis et al., 2021a). UM-BFI 3055 does not preserve the dorsal region of the maxilla, so the first character cannot be assessed. However, it does exhibit a moderate increase in height of the nasal process (i.e., exhibits a low angle of rise of the nasal process). Tis is indeed more consistent with Palaeovaranus , unlike Saniwa orsmaelensis Dollo, 1923 , where the increase is less steep, and Eurheloderma gallicum , where the increase is very steep; different degrees of the rise of the nasal process are also observed in the two Eocene German palaeovaranids, Eosaniwa Haubold, 1977 , from Geiseltal and Paranecrosaurus Smith & Habersetzer, 2021 , from Messel (see Hoffstetter, 1957; Haubold, 1977; Augé, 2005; Georgalis et al., 2021a; Smith & Habersetzer, 2021; Augé et al., 2022). Te widely spaced infoldings of the tooth bases have also been considered a distinctive feature of palaeovaranids, compared to Saniwa and other varanids (see Čerňanský et al., 2024), with palaeovaranids possessing fewer infoldings per tooth compared to varanids ( Smith & Habersetzer, 2021). Tus, UM-BFI 3055 is assigned to Palaeovaranus sp. Te trunk vertebra UM-BFI 3131 does resemble vertebrae assigned to both Glyptosauridae and Palaeovaranus but is matches more to the palaeovaranid morphology in being more anteroposteriorly elongated ( Georgalis et al., 2021a; see also Smith & Habersetzer, 2021). Te seven caudal vertebrae are assigned to Palaeovaranus based on the following characters: (1) elongated and slender vertebra; (2) high neural spine on the posterior region of the neural arch; (3) presence of a medial groove and two lateral ridges on the ventral surface of the centrum; and (4) presence of a pedicellate facet for the chevrons ( Georgalis & Scheyer, 2019; Georgalis et al., 2021a).

A single palaeovaranid species, Palaeovaranus lismonimenos Georgalis et al., 2021a , has been previously described from La Bouffie ( Georgalis et al., 2021a). Nevertheless, the species-level identification among the two, so far, known valid species of Palaeovaranus is principally based on parietal morphology (see Georgalis et al., 2021a). Tus, we assign all these new elements from La Bouffie to Palaeovaranus sp.

Anguimorpha indet.

Figures 23 View Fig , 24 View Fig

Material. One dentary ( UM-BFI 3075); one tooth bearing fragment ( UM-BFI 3099); nine trunk vertebrae ( UM-BFI 3134, UM-BFI 3139, UM-BFI 3180– UM BFI 3183, UM-BFI 3186, UM-BFI 3191, and UM-BFI 3206); and nine caudal vertebrae ( UM-BFI 3143, UM-BFI 3144, UM-BFI 3148, UM-BFI 3186– UM BFI 3188, UM-BFI 3190, and UM-BFI 3204).

Description

Dentary: UM-BFI 3075 is a left dentary preserving most of its median region ( Fig. 23a–c View Fig ). Two recurved caniniform teeth with developed plicidentine folds are preserved ( Fig. 23a, b View Fig ). Te sulcus Meckeli is open ventrolingually ( Fig. 23a View Fig ).

Trunk vertebrae: Te vertebra UM-BFI 3134 is large (6 mm centrum length). Te centrum widens anteriorly

( Fig. 23d, e, g View Fig ). Te cotyle is depressed and wider than the neural canal ( Fig. 23d View Fig ), Te prezygapophyses are strongly inclined dorsally in anterior view ( Fig. 23d View Fig ) and anterolaterally in dorsal view ( Fig. 23f View Fig ). Te neural arch is vaulted

( Fig. 23h View Fig ). Te neural spine extends on the entire length of the neural arch, and overhangs past the posterior margin of the neural arch ( Fig. 23f, h View Fig ). Te ventral surface of the centrum bears a wide and shallow medial keel on its anterior portion ( Fig. 23g View Fig ). UM-BFI 3182, UM-BFI 3183, UM-BFI 3191, and UM-BFI 3206 ( Fig. 23i–m View Fig ) resemble UM-BFI 3134.

UM-BFI 3139 and UM-BFI 3186 differ from UM-BFI 3134 in: (1) having a taller and wider neural canal, as wide as the cotyle ( Fig. 23s–w View Fig ); (2) a centrum wider anteriorly (twice the posterior width; Fig. 23v View Fig ); and (3) a thin, well-marked medial keel on the entire ventral surface length

( Fig. 23v View Fig ). UM-BFI 3181 differs from all other vertebrae in having a broad well marked medial keel on its ventral surface ( Fig. 24a–e View Fig ).

Caudal vertebrae: All vertebrae are anteroposteriorly elongated, with a short neural spine projecting posteriorly ( Fig. 24f–o View Fig ). Teir prezygapophyses are slightly expanded anterolaterally ( Fig. 24h, m View Fig ). Te cotyle is flattened dorsoventrally, and the neural canal is not very high (Fig. h, m). Apart from UM-BFI 3143, remnants of fused neural arches are present on the ventral surface of all vertebrae, and an autotomy septum is present anteriorly ( Fig. 24i, n View Fig ). Some vertebrae ( Fig. 24i View Fig ) also exhibit a median keel on their ventral surface.

Attribution and remarks. Te dentary UM-BFI 3075 exhibits teeth with the same condition as UM-BFI 3055 ( Palaeovaranus ) and UM-BFI 3087 (cf. Eurheloderma ). It lacks any diagnostic characters for either genus, thus can only be assigned to Anguimorpha indet.

Vertebrae UM-BFI 3134, UM-BFI 3181, UM-BFI 3182, UM-BFI 3183, UM-BFI 3191, and UM-BFI 3206 resemble the above vertebrae assigned to Anguinae indet. in: (1) having a depressed centrum but differ in: (1) having a vaulted neural arch; and (2) having a wide and shallow medial keel on its ventral surface. Furthermore, given the high intracolumnar variation observed in vertebrae of modern anguimorphs (e.g., for Anguinae , see Čerňanský et al., 2019), these vertebrae cannot be excluded from glyptosaurids or palaeovaranids. Tus, these are also assigned to an indeterminate anguimorph.

UM-BFI 3139 are interesting. Te presence of a very large neural canal, a very wide centrum anteriorly and a thin medial keel, are reminiscent of “melanosaurine” and helodermatid vertebrae ( Augé, 2005; Georgalis et al., 2021a). Tey do seem to differ from known vertebrae of Eurheloderma in having a thin medial keel on the ventral surface of the centrum and lacking the comma-shaped parapophyses present in Eurheloderma (see Hoffstetter, 1957; Augé, 2005). Te poorly preserved neural spine prevents an assignment to “Melanosaurinae”, and UM-BFI 3139 is thus assigned to an indeterminate anguimorph. It nevertheless seems to represent a further distinct taxon, other than the above-mentioned anguimorphs.

Te caudal vertebrae present a mosaic of several features present in various anguimorph families: (1) cotyle compressed dorsoventrally; (2) haemal arches fused to the centrum; (3) short neural spine projecting posteriorly; (4) presence of an autotomy septum; and (5) presence of a median keel on the ventral surface of the centrum. Although some of these caudal vertebrae are reminiscent of palaeovaranids, the presence of an autotomic septum, precludes such taxonomic assignment, as these are absent from this group ( Georgalis & Scheyer, 2019; Georgalis et al., 2021a; Smith & Habersetzer, 2021). On the other hand, autotomic septa have been documented in caudal vertebrae of glyptosaurids ( Georgalis et al., 2021a, 2021b, 2021c; Rage, 1978), though still there are documented exceptions (e.g., Sullivan, 1979a). Tus,

we are reluctant to assign these specimens to a more precise taxonomic rank within Anguimorpha, and we cannot exclude they (or at least part of them) pertain to some of the above-described anguimorph taxa.

Squamata indet.

Figure 25 View Fig

Material. Four left dentaries ( UM-BFI 3062, UM-BFI 3179, UM-BFI 3084, and UM-BFI 3200); three right dentaries ( MHNT.PAL. 2023.0.31.120, UM-BFI 3071, and UM-BFI 3093); one left lower jaw ( UM-BFI 3205); two left maxillae ( UM-BFI 3091, and UM-BFI 3150); two right maxillae ( UM-BFI 3074, and UM-BFI 3092); three premaxillae ( UM-BFI 3059, UM-BFI 3067, and UM-BFI 3086); and one trunk vertebra ( UM-BFI 3137).

Description and attribution

Dentaries and lower jaw: Te dentary UM-BFI 3093 preserves six teeth ( Fig. 25a–c View Fig ). Teir crown is bicuspid with a small anterior accessory cusp and faint striations

( Fig. 25a, b View Fig ). Biscupid teeth are often present in Eocene lacertids, but this specimen from La Bouffie is too poorly preserved to warrant a more precise assignment. In UM-BFI 3179 ( Fig. 25d–e View Fig ), the dentition resembles a bicuspid condition, but this might also be linked to poor preservation. UM-BFI 3084 seems to have slender straight tricuspid teeth ( Fig. 24f View Fig ) but it cannot be more precisely assigned. Te remaining dentaries ( Fig. 25g –j View Fig ) do not preserve any diagnostic characters that would warrant a more precise assignment within Squamata. Te lower jaw (UM-BFI 3205) is very damaged ( Fig. 25k, l View Fig ). Te lingual view does show the sulcus Meckeli opens ventrolingually, narrowing anteriorly ( Fig. 25k View Fig ). On its anterior region, the sulcus Meckeli opens lingually ( Fig. 25k View Fig ). Tis specimen cannot be more precisely assigned to any squamate group.

Maxillae: UM-BFI 3091 preserves three monocuspid teeth ( Fig. 25m, n View Fig ). UM-BFI 3092 preserves eight teeth, all broken before their apex ( Fig. 25o–q View Fig ). Te teeth are slender and straight with resorption pits at their base

( Fig. 25o View Fig ). UM-BFI 3150 preserves two tricuspid teeth, with faint accessory cusps ( Fig. 25r View Fig ). UM-BFI 3150 resembles maxillae traditionally assigned to pleurodontans (see e.g., Augé, 2005), but is too incomplete to warrant an assignment to a squamate group.

Premaxillae: UM-BFI 3067 is a premaxilla missing the dorsal portion of its nasal process and the right region of the bone ( Fig. 25u–x View Fig ). Te element is unpaired (i.e., both premaxillae fused), with three teeth and one tooth position preserved ( Fig. 25u, v View Fig ). Te teeth are straight and slightly broader at their base ( Fig. 25u, v View Fig ). Tey bear a slightly pointed, unicuspid apex, with striations

( Fig. 25v View Fig ). Te nasal process is broad and has a straight lateral margin ( Fig. 25u–w View Fig ). Te process is triangular in cross-section ( Fig. 25x View Fig ). A small notch is present at its base, delimiting a groove leading to two ethmoidal foramina (opening laterally; Fig. 25w View Fig ); anterior premaxillary foramina are absent. Te posterior surface of the nasal process bears the base of a broad ridge that likely delimits the nasal articulations ( Fig. 25w View Fig ). Interestingly, the broad nasal process has been considered as a diagnostic feature of the genus Geiseltaliellus , however, it is now known that this character is more widespread within Pleurodonta (e.g., in in Suzanniwana and some other Corytophanidae ; see Smith, 2009a). Te supradental shelf is divided into two sections, separated by a deep groove medially ( Fig. 25v View Fig ). Te incisive processes are unfused (i.e., left and right processes separated by a deep groove medially; Fig. 25v View Fig ) and moderately developed ( Fig. 25v View Fig ). Te maxillary process is small, with a well-marked maxillary articulation facet dorsally ( Fig. 25u, w View Fig ). As a further note, if the left premaxillary process of UM-BFI 3067 is complete, it would seem to indicate an unusually complicated articulation with the maxilla, which could be taxonomically informative. Smith (2006, 2011a) documented an unusual articulation of the premaxilla with the maxilla in the extant polychrotid pleurodontan Polychrus Cuvier, 1817 , and its fossil stem, in which the premaxilla overlaps the maxilla; it is not though certain whether something similar could happen in the La Bouffie premaxilla. Tese being said, it is possible that UM-BFI 3067 pertains to pleurodontans, but this taxonomic determination cannot be certain. UM-BFI 3059 ( Fig. 25s, t View Fig ) has a somehow similar morphology as UM-BFI 3067 but is very fragmentary.

UM-BFI 3086 is a very fragmentary premaxilla, with only part of the right region preserved ( Fig. 25y View Fig –aa). Two teeth and one additional tooth position are preserved ( Fig. 25y View Fig –aa). Te teeth are small with a rounded apex ( Fig. 25y View Fig ), without any striations. Te supradental shelf does not protrude posteriorly ( Fig. 25z View Fig ). Although broken, the vomerine and incisive processes are present

( Fig. 25 View Fig aa). Te base of the nasal process is preserved and seems to widen dorsally ( Fig. 25y View Fig ). A small notch suggests an ethmoidal foramen is present ( Fig. 25z View Fig ). A small but well delimited maxillary facet is preserved on the dorsal surface. Tese three premaxillae represent two distinct taxa but cannot be securely assigned to a precise squamate group.

Trunk vertebra: Te last specimen, UM-BFI 3137, is a small trunk vertebra ( Fig. 25 View Fig ab–af). Te prezygapophyseal articular facets are small and circular ( Fig. 25 View Fig ab). A developed zygosphene and zygantrum are present

( Fig. 25 View Fig ac, ae). Te neural arch is not very vaulted, and the neural spine is broken near its base ( Fig. 25 View Fig ad). Te latter structure does extend on the entire length of the neural arch and overhang past the posterior margin of the neural arch ( Fig. 25 View Fig ab, ad). Te centrum widens anteriorly, and the cotyle extends ventrally on the ventral surface of the centrum ( Fig. 25 View Fig ac). A developed median ridge is present on the ventral surface of the centrum ( Fig. 25 View Fig ac). UM-BFI 3137 is also interesting. Te presence of a true zygosphene-zygantrum complex is known in several lizard families (e.g., Pleurodonta, Teiidae , some large Lacertidae , and of course, snakes; Hoffstetter & Gasc, 1969; Szyndlar & Georgalis, 2023; Bourque & Stanley, 2025) present in La Bouffie. UM-BFI 3137 differs from the only trunk vertebra assigned to Tupinambinae from Quercy (specimen MNHN.F.PRR2006 from the MP 17 locality of Perrière; see Augé & Brizuela, 2020: fig. 5) in having a well-developed median ridge on the ventral surface of the centrum (vs. flattened centrum in MNHN.F.PRR2006) and being more elongated anteroposteriorly, however, it should be noted that both these features can be observed in extant tupinambines (see Bourque & Stanley, 2025).