taxonID	type	description	language	source
03D16C36FFDDFFE64F4CFB207D81F824.taxon	description	(Figs 1; 2)	en	Szyndlar, Olaf Lizak Zbigniew, Delfino, Massimo, Georgalis, Georgios L. (2026): First fossil remains of the extant colubrid Zamenis situla (Linnaeus, 1758) (Serpentes) from the island of Crete, Greece. Comptes Rendus Palevol 25 (7): 125-136, DOI: 10.5852/cr-palevol2026v25a7, URL: https://doi.org/10.5852/cr-palevol2026v25a7
03D16C36FFDDFFE64F4CFB207D81F824.taxon	materials_examined	MATERIAL EXAMINED. — Greece • Two anterior trunk vertebrae (UU RE 408 and UU RE 409); 40 trunk vertebrae (UU RE 406, UU RE 407, UU RE 410, UU RE 411, UU RE 412, UU RE 414, UU RE 417, UU RE 418, UU RE 419, and UU RE 416 [31 vertebrae]); and one caudal vertebra (UU RE 415).	en	Szyndlar, Olaf Lizak Zbigniew, Delfino, Massimo, Georgalis, Georgios L. (2026): First fossil remains of the extant colubrid Zamenis situla (Linnaeus, 1758) (Serpentes) from the island of Crete, Greece. Comptes Rendus Palevol 25 (7): 125-136, DOI: 10.5852/cr-palevol2026v25a7, URL: https://doi.org/10.5852/cr-palevol2026v25a7
03D16C36FFDDFFE64F4CFB207D81F824.taxon	description	DESCRIPTION Several trunk and a single caudal vertebrae are available in our sample. Trunk vertebrae are longer than wide, with a centrum length to neural arch width ratio over 1.0. There are two anterior trunk vertebrae, which are mainly characterized by the presence of hypapophysis instead of haemal keel. Their centrum lengths are equal to 3.4 mm. In the anterior trunk vertebrae UU RE 408 and UU RE 409 (Fig. 1), in anterior view (Fig. 1 A, F), the zygosphene is thin, the prezygapophyseal articular facets are almost horizontal. The cotyle is orbicular in shape. The neural canal is higher than wide. In posterior view (Fig. 1 B, G), the neural arch is vaulted, with a vaulting ratio (sensu Georgalis et al. 2021) equal to 0.45. The condyle is orbicular. In lateral view (Fig. 1 C, H), the neural spine of anterior trunk vertebrae is prominent and of medium height, overhanging both anteriorly and posteriorly. The centrum is wider than it is tall. The interzygapophyseal ridges are very weakly defined. The paradiapophyses are clearly divided into distinct diapophyses and parapophyses. Subcentral ridges extend longitudinally from the parapophyses to the beginning of the condyle. A hypapophysis is present, elongated, somewhat linear in shape, and pointy at the posterior end. It is only slightly flattened ventrally and almost completely straight dorsally. Lateral foramina are present, below the level of the interzygapophyseal ridges. In dorsal view (Fig. 1 D, I), the zygosphene possesses two lateral lobes, although its mid-part is damaged. The prezygapophyseal articular facets are slightly elongated laterally. The neural spine commences posteriorly to the level of the zygosphene, crossing around 3 / 5 of the entire midline’s length. The interzygapophyseal constriction is deep. In ventral view (Fig. 1 E, J), the hypapophysis is thin anteriorly and thickens posteriorly. The postzygapophyseal articular facets are damaged but seem to be more circular than oval in shape and do not extend beyond the level of the condyle. The prezygapophyseal accessory processes are short and point laterally. The subcentral grooves are shallow. It is worth noting that UU RE 408 (Fig. 1 A-E) is a pathological specimen, because of the deformity of the left paradiapophysis. Mid-trunk to posterior trunk vertebrae (e. g., UU RE 406, UU RE 407, UU RE 410, UU RE 414, UU RE 412, UU RE 411, UU RE 417; Figs 1 K-T; 2 A-O) are principally characterized by the presence of haemal keel instead of hypapophysis. Their centrum lengths are between 3.5 mm to 3.9 mm. In anterior view (Figs 1 K, P; 2 A, K) the zygosphene is thin, and the prezygapophyses are almost horizontal, only slightly elevated. Paracotylar foramina are present, situated one on each side of the cotyle; they can be occasionally large. The cotyle is orbicular. The neural canal is more square-like in shape ventrally but circular dorsally. In posterior view (Figs 1 L, Q; 2 B, L), the neural arch is relatively depressed, with a vaulting ratio (sensu Georgalis et al. 2021) equal to around 0.25. The neural arch is more depressed in UU RE 417 (Fig. 2 L), but can be occasionally slightly more vaulted as in UU RE 407 (Fig. 1 Q) or UU RE 410 (Fig. 2 B). The condyle is orbicular. In lateral view (Figs 1 M, R; 2 C, H, I, M), the neural spine is shorter and more elongated than in anterior trunk vertebrae, although it still overhangs anteriorly and posteriorly. The interzygapophyseal ridges are prominent. The subcentral ridges are thick and raised. The haemal keel is well-defined ventrally, with a “ step ” of varying degree that can be observed in the material: it is absent in UU RE 407 (Fig. 1 R), visible in UU RE 406 and UU RE 411 (Figs 1 M; 2 I), and very deep in UU RE 410, UU RE 412, and UU RE 417 (Fig. 2 C, H, M). Lateral foramina are visible. The paradiapophyses form distinct parapophyseal and diapophyseal portions. The diapophyses are oriented slightly posteriorly, whereas the parapophyses are oriented more ventrally rather than anteriorly or posteriorly, and are either almost the same size as the diapophyses like in UU RE 407 (Fig. 1 Q) or only slightly larger like in UU RE 406 (Fig. 1 R). In dorsal view (Figs 1 N, S; 2 G, N), the prezygapophyseal articular facets are oval in shape and elongated laterally. The neural spine covers around two-thirds of the entire midline length of the neural arch, similarly to the preceding anterior trunk vertebrae, though it is somehow anteroposteriorly longer. The zygosphene is triangular and possesses two lateral lobes and a median one. The prezygapophyseal accessory processes are more pronounced and longer than in the anterior trunk vertebrae, but not longer than half the greatest length of the prezygapophyseal articular facets. Their tips can be more obtuse like in UU RE 406 (Fig. 1 N), or acute like in UU RE 407 (Fig. 1 S). The interzygapophyseal constriction is deeper than in the anterior trunk vertebrae. The posterior median notch of the neural arch is deep. In ventral view (Figs 1 O, T; 2 D, E, F, J, O), the centrum is wider than long. The haemal keel is relatively thick. It is thicker in its posterior portion but narrows slightly in its anterior section; its maximum width is observed near both its anteriormost and posteriormost margins. This narrowing of the haemal keel is more prominent in UU RE 407, UU RE 414, and UU RE 411 (Figs 1 T; 2 E, J) than in UU RE 406, UU RE 410, and UU RE 417 (Figs 1 O; 2 D, O). The postzygapophyseal articular facets are oval in shape, elongated laterally, and do not extend beyond the level of the condyle. The subcentral grooves are deep. Posterior trunk vertebrae are very similar to mid-trunk vertebrae, but can be differentiated from the preceding mid-trunk vertebrae by a relatively more depressed neural arch, the prominent and very wide haemal keel, and relatively deeper subcentral grooves (Fig. 2 K-O). A single caudal vertebra, UU RE 415 (Fig. 2 P-T), is available in our fossil sample. Its centrum length is equal to 1.7 mm. In anterior view (Fig. 2 P), the zygosphene is thinly built. Paracotylar foramina are present. The neural canal is still flattened laterally and circular dorsally. The cotyle is orbicular. The pleurapophyses and haemapophyses are mostly broken off, though it still can be seen that the pleurapophyses are ventrally oriented with wide gap between them and the prezygapophyses. In posterior view (Fig. 2 Q), the neural arch is relatively vaulted and almost semicircular in shape, with a vaulting ratio (sensu Georgalis et al. 2021) equal to 0.38. The condyle is orbicular. In lateral view (Fig. 2 R), the neural spine is higher than in the mid-trunk vertebrae and overhangs only anteriorly. The interzygapophyseal ridges are still visible; the subcentral ridges are not easily distinguishable. Lateral foramina are present. In dorsal view (Fig. 2 S), the prezygapophyseal articular facets are oval in shape and elongated anteriorly. The neural spine covers, again, around 3 / 5 of the entire midline length of the neural arch. The interzygapophyseal constriction is deep. The zygosphene is triangular with three prominent lobes. The prezygapophyseal accessory processes are short and point anteriorly. In ventral view (Fig. 2 T), the prezygapophyseal accessory processes are still recognisable but much less pronounced. The prezygapophyses are very short laterally, and the prezygapophyseal accessory processes only slightly go beyond the length of the prezygapophyseal articular facets. The pleurapophyses have a wide base, covering around half of the ventral surface of the centrum. The postzygapophyseal articular facets are oval in shape and elongated posteriorly. SKELETAL ANATOMY OF ZAMENIS SITULA Even though Zamenis situla is a ubiquitous element of Greek and many other European herpetofaunas, its skeletal morphology has not been so far comprehensively investigated, for example only a few works have so far dealt with some parts of its skull (e. g., Szunyoghy 1932; Bogert 1947). We therefore take this opportunity to provide some observations on the skull and vertebral column morphology of this species, though a complete bone by bone cranial documentation is beyond the scope of this paper. The intranasal (Fig. 3 A, B, C) is slightly curved, widens laterally and ventrally at around mid-length. This expansion bears the ascendens nasal process that is directed dorsolaterally. The intranasal is convex dorsally and concave ventrally, and at its posterior end a frontal process is located, that points laterally. The vomer (Fig. 3 D) possesses well-pronounced premaxillary and posterior-inferior processes, but the postero-superior process is less developed; the lamina spheroidea palatina is shifted posteriorly. The vomerine foramen is relatively large and oval in shape. The basiparasphenoid (Fig. 3 E, F) has a central area, that is distinct from the lateral area. The basisphenoid crest is well-developed, with suborbital flanges being distinct. The parasphenoid process possesses a deep groove on the ventral side, that culminates in width just before the suborbital flanges. The basipterygoid processes are very subtle. The pterygoid crests project ventrally and are inclined along half of their length, making the central area bridge-like in appearance. Above the midpoint of each pterygoid crest, and approximately in the centre of the lateral area, the anterior orifices of the Vidian canals are located. The openings of the anterior orifices of the Vidian canals are oriented anteriorly. The basisphenoid crest is well pronounced only in its anterior part, diminishing posteriorly and ending well before the posterior edge of the bone. The postpterygoid area shows a visible constriction on its surface due to the presence of the posterior orifices of the Vidian canals, whose openings are oriented posterolaterally. The frontal crest, located on the dorsal surface of the bone, has a pointed base that ends beyond the anterior edge of the parasphenoid process, which also has a pointed end. The frontal crest is located just below half of the length of the parasphenoid process. The palatine (Fig. 3 G, H) possesses 12 teeth, distributed almost throughout its entire length. The maxillary process points posterolaterally; the choanal process runs anteromedially but is relatively curved at the end, pointing laterally. The maxilla (Fig. 3 I) possesses 19 tooth positions along its length. The prefrontal process is present at approximately the level of the 8 th- 9 th tooth position and points posteromedially. The ectopterygoid process is present at the level of the 17 th tooth position and points anteromedially. The frontal (Fig. 3 J, K) is almost straight, widening at its distal part. The prefrontal (Fig. 3 L) has a lacrimal foramen, with another foramen also visible on its lateral surface. On its mediodorsal side, where it is connected with the frontal, there is a process that points posterodistally. The pterygoid (Fig. 3 M, N) has a spatula-like shape. It is broad in its posterior portion but narrow in the anterior one. The anterior portion has 14 teeth and is terminated into two branched processes, of which the medial one is longer. The ectopterygoid (Fig. 3 O) is Y-shaped and elongated posteriorly. Anteriorly it bears two branches: the medial one is pointed, while the lateral one is broad. The parietal (Fig. 3 P) has an anterior border forming a broad U-shape. The parietal crests converge just before the posterior border, which is almost semicircular. This part of the parietal connects to the supraoccipital, which features a well-developed sagittal crest and occipital crests. Supraoccipital foramina are present. The prootic (Fig. 3 Q) has anterior and posterior trigeminal foramina that have irregular shapes; a small facial nerve foramen can be seen. The exoccipital (Fig. 3 R, S) has not a well-developed occipital crest. The parotic process and protuberantia postoccipitalis are clearly visible but not well developed. The vagus-hypoglossal nerve foramen is clearly visible. The exoccipital condyle is triangular in shape in lateral view. The basioccipital (Fig. 3 T) is somewhat pentagonal in shape with a flattening at its anterior border. The crests on the basioccipital are clearly visible. The quadrate (Fig. 3 U, V, W) possesses a dorsal crest and is not highly tilted, remaining almost horizontal with a slight curvature, giving it an almost T-shape. The quadrate crest is visible, and the stapedial process is well-pronounced. The dentary (Fig. 3 X, Y) possesses 21 tooth positions. An elongated mental foramen is present at the level of 9 th- 10 th tooth, and the compound notch closes at approximately the level of 13 th tooth. The dorsal and ventral processes at the posterior end of the dentary are prominent. The compound bone (Fig. 3 Z, ZA, ZB) features an angular retroarticular process that points ventrally. Its posterior articular facet is not very deep. The prearticular crest is clearly separated from the base of the bone. The mandibular fossa is deep, with a foramen visible in dorsal view. The supraangular foramen (sensu Szyndlar 1984) is present in lateral view, and another foramen is visible on the retroarticular process in medial view. The axis of Zamenis situla has a typical colubrid morphology (Fig. 4 A). In anterior view, the transverse processes are short. The neural canal is considerably wider than in other parts of the column. In dorsal view, the zygosphene is rather wide and concave. The neural spine is high. In lateral view, the neural spine overhangs both anteriorly and posteriorly, with the anterior overhanging being shorter than the posterior. The hypapophysis is projecting anteroventrally in similar fashion to the anterior trunk vertebrae. As in all colubrids, anterior trunk vertebrae are characterized by the presence of a hypapophysis (Fig. 4 B). These vertebrae have also an anteroposteriorly shorter centrum, smaller prezygapophyseal articular facets, and a more vaulted neural arch (Fig. 4 B). In succeeding trunk vertebrae, the hypapophysis is substituted by a haemal keel (Fig. 4 C). This haemal keel becomes progressively wider in ventral view, towards the posterior mid- and posterior portion of the trunk column. The neural spine in these vertebrae is shorter and the neural arch becomes gradually more depressed. These vertebrae are more elongated when compared with anterior trunk vertebrae. The prezygapophyseal accessory processes are more pronounced. As typical for snakes, cloacal vertebrae are characterised primarily by the presence of lymphapophyses (Fig. 4 D). The lymphapophyses possess a relatively wide gap, with clear separation of dorsal and ventral branches, that are running ventrolaterally. Progressing in posterior direction, the vertebrae become shortened and relatively wider. In this part of the vertebral column, the neural spine overhangs primarily posteriorly, with this trend persisting across succeeding caudal vertebrae. The prezygapophyseal accessory processes are shorter in this part of the column. A prominent (but not so thick) haemal keel is present on the ventral surface of the centrum of the cloacal vertebrae. Caudal vertebrae (Fig. 4 E, F) are characterized primarily by the presence of pleurapophyses and haemapophyses. In anterior view, pleurapophyses are elongated and ventrolaterally oriented (Fig. 4 E) but they shorten and gradually become more ventrally oriented in succeeding caudal vertebrae (Fig. 4 F). The gap between prezygapophyses and pleurapophyses successively widens, in the posterior portion of the tail. The neural arch gets more vaulted. The prezygapophyseal and postzygapophyseal articular facets progressively become more oval in shape (in dorsal and ventral views respectively) and oriented more anterodorsally than laterally. Paired haemapophyses emerge from the ventral surface of the centrum; these are more or less parallel to each other in anterior caudal vertebrae (Fig. 4 E) but towards the posterior caudal series, their distal ends approach closer to each other (Fig. 4 F).	en	Szyndlar, Olaf Lizak Zbigniew, Delfino, Massimo, Georgalis, Georgios L. (2026): First fossil remains of the extant colubrid Zamenis situla (Linnaeus, 1758) (Serpentes) from the island of Crete, Greece. Comptes Rendus Palevol 25 (7): 125-136, DOI: 10.5852/cr-palevol2026v25a7, URL: https://doi.org/10.5852/cr-palevol2026v25a7
