Elaphe sp.

Ivanov, Martin, 2002, The oldest known Miocene snake fauna from Central Europe: Merkur-North locality, Czech Republic, Acta Palaeontologica Polonica 47 (3), pp. 513-534 : 522-523

cf. Elaphe sp.

Type species: Elaphe parreyssii Fitzinger, 1833 = Elaphe quatuorlineata sauromates ( Pallas, 1811) .

Material.—One left dentary (SGDB Ah−168), 50 trunk vertebrae (SGDB Ah−169–215; SGDB Ah−617–619).

Dentary ( Fig. 6A 1 , A 2 ).—The caudal part of this gracile, fragmentary bone is broken off. The rostral part is markedly curved medially. The Meckel’s groove is completely enclosed at the level of the 4 th and 5 th teeth. The rostral termination of the notch for the compound bone occurs at the level of the 13 th tooth. Because of the fragmentary condition of the bone, it is not possible to determine the number of the teeth.

Trunk vertebrae ( Fig. 6B 1 –B 5 ).—In lateral view, the neural spine of the largest vertebra is about 1.5–2 times longer than high and the dorsal margin is not thickened. The cranial margin of the neural spine slightly overhangs anteriorly and the caudal margin overhangs posteriorly. The interzygapophyseal ridges are sharp. The conspicuous lateral foramina are not in depressions. The subcentral ridges are indistinct and slightly arched dorsally. The condyle is situated on a very short neck. The paradiapophyses are distinctly divided and the ventral margin of the parapophyses is rounded with short parapophyseal processes. In dorsal view, the cranial margin of the zygosphene has distinct lateral lobes, a wide median lobe is also prominent in smaller vertebrae and in the largest vertebrae the median lobe can be absent. The prezygapophyseal articular facets are oval to subtriangular and the prezygapophyseal processes are clearly shorter than the prezygapophyseal facets. The epizygapophyseal spines are well developed. In ventral view, the indistinct subcentral grooves are shallow and the subcentral foramina are very small. The haemal keel expands near the cotylar rim and the paracotylar tubercles are lacking. The rounded subrectangular postzygapophyseal articular facets are enlarged laterally. In cranial view, the neural arch is moderately vaulted and the neural canal is approximately circular with short lateral sinuses. The zygosphenal lip is straight to slightly convex. Paracotylar foramina are occur on both sides of the rounded cotyle. Measurements are as follows (n = 20): cl: or = 2.90–4.18 mm; naw: or = 2.31–3.15 mm; cl/naw: or = 1.17–1.43, mean 1.32±0.08.

Comments.—The very fragmentary dentary is identified as probablybelongingtothegenus Elaphe basedontheposition of the rostral closure of Meckel’s groove and the position of the rostral termination of the notch for the compound bone. The mental foramen is very short which is typical for some small representatives of the genus Elaphe . Because of the fragmentary condition of the bone, it is not possible to estimate the precise number of teeth in the ramus, thus the identification remains disputable.

The vertebrae have a relatively long neural spine overhanging both anteriorly and posteriorly, pointed prezygapophyseal processes and a crenate zygosphene (that is convex in cranial view). All of these features are typical for some small extant representatives of the genus Elaphe , especially E. situla . Vertebrae of cf. Elaphe sp. from Merkur−North differ from the majority of the European representatives of the

A1 B 1

B3

B 2

genus Elaphe by having well developed epizygapophyseal spines. The precise determination of small representatives of the subfamily Colubrinae is often very difficult without cranial bones (see above). If the vertebrae actually belong to the genus Elaphe , then this fossil represents the oldest known record of this genus. At present, the oldest probable representative of Elaphe is known from the German Middle Miocene (MN 5/6) Oggenhausen site (“cf. Elaphe sp. ” by Szyndlar and Schleich 1993). The oldest known certain occurrence of the genus Elaphe , Elaphe kansensis ( Gilmore, 1938) is reported from the Middle Miocene of Nebraska ( Gilmore 1938; Holman 1964, 2000).

Figures

Fig. 6. cf. Elaphe sp. from the Early Miocene (MN 3a) of Merkur−North. A1, A2. Left dentary (SGDB Ah−l 68). B1–B5. Mid−trunk vertebra (SGDB Ah−215). In lingual (A1), labial (A2), lateral (B1), dorsal (B2), ventral (B3), cranial (B4), and caudal (B5) views. Scale bar 2 mm.

Fig. 1. The distribution of some Early and Middle Miocene ophidian localities in the areas of Germany, Czech Republic, Slovak Republic, Poland and Austria. 1, Weisenau (MN 1); 2, Hessler (MN 1); 3, Ulm−Westtangente (MN 2); 4, Stubersheim 3 (MN 3); 5, Merkur−North (MN 3a); 6, Dolnice (MN 4); 7, Petersbuch 2 (MN 4); 8, Langenau (MN 4); 9, Oberdorf (MN 4); 10, Randecker Maar (MN 5); 11, Eichstätt (MN 4–6); 12, Ivančice (MN?4–6); 13, Oggenhausen (MN 5/6); 14, Przeworno (MN 5–6); 15, Devínska Nová Ves (MN 6); 16, Vösendorf; 17, Sandelzhausen (MN 6); 18, Rothenstein 13 (MN 6); 19, Opole (MN 7); 20, Öhningen (MN 7+8); 21, Steinheim am Albuch (MN 7+8).

Fig. 2. Bavarioboa sp. from the Early Miocene (MN 3a) of Merkur−North; A1–A4. Cervical vertebra (SGDB Ah−2). B1–B5. Mid−trunk vertebra (SGDB 7408/MI−1). In lateral (A1, B1), dorsal (A2, B2), ventral (A3, B3), cranial (A4, B4), and caudal (B5) views. Scale bar 2 mm.

Fig. 5. Coluber caspioides Szyndlar and Schleich, 1993 from the Early Miocene (MN 3a) of Merkur−North. A1, A2. Left frontal (SGDB Ah−44). B. Right palatine (SGDB Ah−46). C1, C2. Right pterygoid (SGDB Ah−45). D. Right quadrate (SGDB Ah−l 1). E. Left dentary (SGDB Ah−48). F1, F2. Right compound bone (SGDB Ah−49). G1–G5. Cervical vertebra (SGDB Ah−51). H1, H2. Mid−trunk vertebra (SGDB Ah−615). I1–I5. Posterior trunk vertebra (SGDB 7408/MI−37). In dorsal (A1, C1, G2, H2, I2), ventral (A2, B, C2, G3, I3), postero−lateral (D), labial (E, F1), lingual (F2), lateral (G1, H1, I1), cranial (G4, I4), and caudal (G5, I5) views. Scale bar 2 mm.