Lacerta Linnaeus, 1758

Lacerta Linnaeus, 1758

cf. Lacerta sp.

Figure 35 View Fig

Material. Spilia 1: one dentary ( UU SP1 1002); Spilia 3: one premaxilla ( UU SP3 677), two maxillae ( UU SP3 606 and UU SP3 609), and two dentaries ( UU SP3 602 and UU SP3 603).

Description.

Te premaxilla (UU SP3 677) from Spilia 3 is moderately large-sized ( Fig. 35a, b View Fig ): the preserved width of the broken dental shelf is at least 2.5 mm. It has a rather short and leaf-shaped ascending nasal process. On the external surface, a strong dermal sculpturing covers the distal half of the process. On the internal surface, the septonasal crest is rather sharp; it reaches the dorsal end of the process. Te alveolar portion bears at least five pleurodont, cylindrical and slender teeth, none of which is well preserved. Te palatal processes are well separated by a middle V-shaped notch, in which the incisive process is lodged.

Te fragmentary maxillae from Spilia 3 ( Fig. 35c–f View Fig ) preserve only a small part of the midventral portion of the bone, which is about 3.2 mm in length in UU SP3 609

( Fig. 35e, f View Fig ) and about 3.7 mm in UU SP3 606 ( Fig. 35c, d View Fig ). Tey carry pleurodont, closely-spaced, cylindrical, and not expanded teeth, with mono- and bicuspid crowns. On the medial surface of the preserved portion of the facial process of UU SP3 609 ( Fig. 35e View Fig ), a small structure located by the anterodorsal corner of the fragment is most likely the remain of a well-developed carina maxillaris (sensu Müller, 1996). In both specimens, the lateral surface displays two medium-sized ventrolateral foramina and the base of a strong dermal sculpturing cover.

Te dentaries from Spilia 1 and Spilia 3 are also medium sized, even though poorly preserved ( Fig. 35g – l View Fig ). Te preserved portion, which represents either part of the middle portion of the bone (UU SP1 1002; Fig. 35g, h View Fig ) or its anterior end (other specimens), is 7 mm (UU SP1 1002), 5.4 mm (UU SP3 602; Fig. 35i, j View Fig ) or about 6.2 mm (UU SP3 603; Fig. 35k, l View Fig ). A moderately high subdental shelf is present medially, showing a subdental ridge and a shallow sulcus dentalis dorsally. Te shelf narrows posteriorly in UU SP1 1002 ( Fig. 35i View Fig ). Anteriorly, the subdental shelf ends in a narrow and subhorizontal mandibular symphysis. Te Meckelian fossa is narrow anteriorly, but enlarges posteriorly. Te ventral margin of the dentary is convex. Te teeth are pleurodont, cylindrical, closely spaced and not expanded. Te most preserved teeth display either a mono- or a bicuspid crown. Te lateral surface of the dentary is smooth, with few mental foramina.

Remarks. Te morphological features displayed by these fossil remains from Spilia allow their attribution to a lacertid lizard, the size of which is comparable with that of a medium-sized taxon. Significant features supporting the lacertid nature of these remains are (Augé, 2005; Černanský & Syromyatnikova, 2019; Čerňanský et al., 2016; Villa & Delfino, 2019a): the V-shaped notch of the premaxilla; the presence of a subdental ridge associated with a sulcus dentalis; the wide and open Meckelian fossa; the convex ventral margin of the dentaries; and the heterodont dentition composed of pleurodont and either mono- or bicuspid teeth. Te short and leaf-shaped nasal process of the premaxilla is found in Lacerta , Timon Tschudi, 1836 , and Zootoca Wagler, 1830 , among extant European lacertids (Barahona & Barbadillo, 1997; Villa & Delfino, 2019a). Premaxillae of Zootoca are generally smaller than the one from Spilia, whereas those of adult Timon are distinctly larger. UU SP3 677 fits on the other hand within the size range of Lacerta (Villa & Delfino, 2019a) , to which the herein-described medium-sized fossils could therefore be related. It has to be noted, however, that an identification based mainly on size should be treated with caution and considered only as tentative. Čerňanský and Syromyatnikova (2019) reported a very wide nasal process in Lacerta agilis Linnaeus, 1758 , and a less wide process in other species of Lacerta . If the Spilia premaxilla indeed belonged to Lacerta , the moderate width of its nasal process would suggest that it does not pertain to the former taxon.

Lacertidae indet. (small-sized)

Figure 36 View Fig

Material. Spilia 4: one coronoid ( UU SP4 704).

Description.

Tis coronoid (UU SP4 704) from Spilia 4 is very small

( Fig. 36 View Fig ). Both the anterior and posterior tips are broken. Te anterior half is clearly divided into an anteromedial and a labial processes. Te latter is smaller than the former, but not reduced. Te coronoid process is well developed and dorsally directed, with a rounded distal end. Te posteromedial process is wide. A short and rounded posterior process is present, thus defining a distinct notch on the posterior margin of the coronoid. A well-developed coronoid ridge stands out on the medial side of the bone. In dorsal view, a clear medial concavity is recognizable.

Remarks. UU SP4 704 clearly pertains to a lacertid lizard due to the following combination of features (Villa & Delfino, 2019a): not reduced labial process; wide posteromedial process; clear medial concavity in dorsal view; presence of the posterior process. Te dorsally-directed coronoid process is a widely distributed feature in lacertids, thus not allowing a precise identification of this isolated element. However, it is indicative of an adult condition (Villa & Delfino, 2019a). Given its very small size, UU SP4 704 is therefore evidence for the presence in the Spilia 4 assemblage of a second lacertid taxon, the adults of which were small in size.

Lacertidae indet.

Figures 37 View Fig , 38 View Fig

Material. Spilia 1: one dentary ( UU SP1 1001); Spilia 3: two dentaries ( UU SP3 608 and UU SP3 610) and one fragment of indeterminate tooth bearing bone ( UU SP3 607); Spilia 4: one maxilla ( UU SP4 638), five dentaries ( UU SP4 603, UU SP4 604, UU SP4 611, UU SP4 636, and UU SP4 637), and two fragments of indeterminate tooth bearing bones ( UU SP4 504 and UU SP4 650); Rema Marmara : two dentaries ( UU RMA 302 and UU RMA 303).

Description.

Te fragment of a left maxilla (UU SP4 638) from Spilia 4 is small and poorly preserved ( Fig. 37a, b View Fig ). It carries pleurodont, cylindrical, closely-spaced and bicuspid teeth. A wide and posteriorly directed supradental foramen is preserved. Te preserved portion of the lateral surface is smooth, with few moderately large, ventrolateral foramina.

Te dentaries from the Spilia localities ( Fig. 37c–h View Fig ) are small and very fragmentary, with the exception of UU SP4 603 that preserves most of the tooth row ( Fig. 37g, h View Fig ). Teir teeth are similar to those of the maxilla, but they can be either bi- or tricuspid. Tey bear a narrow subdental shelf with a distinct subdental ridge. Te mandibular symphysis, preserved in UU SP4 603 ( Fig. 37g, h View Fig ) and UU SP4 636, is narrow and subhorizontal. Te Meckelian fossa is wide and medially open. When preserved, the ventral margin of the bone is convex. Te lateral surface is smooth, with few mental foramina. UU SP4 603 bears five mental foramina (the posteriormost one being slightly larger than the others) and at least 24 tooth positions ( Fig. 37g, h View Fig ). Te alveolar foramen is located roughly between the 22nd and the 23rd tooth positions.

Other tooth bearing bones from Spilia carry pleurodont, cylindrical and closely-spaced teeth, which are bicuspid. Tooth bases are not swollen. Te fragments are rather small and not so robustly built.

Te two small fragments of dentaries from Rema Marmara are very poorly preserved ( Fig. 38 View Fig ). Both represent only a small portion of the middle part of the bone, likely originally located close to the anterior end. Medially, the Meckelian fossa is open. Te opening faces medially in UU RMA 302 ( Fig. 38b View Fig ) and more ventrally in UU RMA 303

( Fig. 38c View Fig ), indicating that the latter fragment was located more anteriorly than the former one in origin. Tis is also supported by the height of the subdental shelf, which is proportionally high in both fragments, but to a higher degree in UU RMA 303 ( Fig. 38c View Fig ). Te shelf clearly narrows posteriorly in UU RMA 302 ( Fig. 38b View Fig ). Dorsally, the subdental shelf bears a subdental ridge and a sulcus dentalis. Te ventral margin of the bone is convex. Te lateral surface is smooth, with few small mental foramina. Both fragments preserve a few teeth, together with empty tooth positions. UU RMA 302 displays four well-preserved teeth, plus a single empty tooth position ( Fig. 38a, b View Fig ). On the other hand, UU RMA 303 hosts only one well-preserved tooth (even though the crown is rather worn), two fragments of tooth bases, as well as two empty tooth positions ( Fig. 38c View Fig ). Te preserved teeth are closely spaced, pleurodont, slender, and cylindrical. Te tooth bases are not expanded. In all teeth, the crowns bear a large main cusp and a smaller accessory cusp located mesially. Tis accessory cusp is less evident in the posteriormost tooth of UU RMA 302 ( Fig. 38a, b View Fig ) and in the single well-preserved one of UU RMA 303 ( Fig. 38c View Fig ), either because of lower development of the cusp itself or wearing. Striae are visible on the lingual side of the crown, but not on the labial one. In both specimens, about one third of tooth height is laterally exposed.

Remarks. Te fossil remains from Spilia all share lacertid features, particularly in the tooth morphology. However, their preservational status does not allow a clear identification. Te smallest specimens may pertain to the above-mentioned small taxon that was present at Spilia, but it is not possible to confidently exclude that these elements are juveniles of the larger one and so they are here identified only as indeterminate lacertids. Te two dentary fragments from Rema Marmara clearly belong to indeterminate lacertids, due to their tooth morphology, the presence of an open Meckelian fossa and a subdental ridge, and the convex ventral margin (Augé, 2005; Černanský & Syromyatnikova, 2019; Villa & Delfino, 2019a). Te very poor preservation of the specimen hinders any further identification.