Naja, Laurenti, 1768

Ivanov, Martin, 2000, Snakes of the lower / middle Miocene transition at Vieux Collonges (Rhône, France), with comments on the colonisation of western Europe by colubroids, Geodiversitas 22 (4), pp. 559-588 : 579-580

Naja sp. 1

Part – Palaeonaja romani Hoffstetter, 1939 . — Rage 1984: 54.

Part – Naja cf. N. romani (Hoffstetter, 1939) . — Szyndlar & Rage 1990: 387, fig. 1.

Naja sp. 2 – Ivanov 1997a: 132-134, fig. 61.

MATERIAL EXAMINED. — 4 cervical vertebrae ( FSL 369141- FSL 369144), 52 trunk vertebrae ( FSL 369145- FSL 369177, FSL 369178- FSL 369196).

DESCRIPTION

Cervical vertebrae ( Fig. 13 A-D)

In lateral view, the neural spine is lower than long, both its cranial and caudal margins are inclined posteriorly. A dorsal expansion of the neural spine is not observed. The distal tip of the hypapophyses is broken off; fragmentary hypapophyses are directed postero-ventrally. The interzygapophyseal ridges are short but distinct. The lateral foramina situated in relatively deep depressions are well visible. In dorsal view, the vertebral centrum is narrow, the cranial margin of the damaged zygosphene exhibits originally weakly developed lateral lobes and the median lobe. The prezygapophyseal articular surfaces are oval to subtriangular. Epizygapophyseal spines are well-developed. In ventral view, both the subcentral ridges and grooves are relatively welldeveloped, the subcentral foramina are distinct. The postzygapophyseal articular surfaces are irregularly shaped. In cranial view, the zygosphenal lip is considerably convex, the neural canal is circular with small lateral sinuses. Small subcotylar tubercles occur under the ventral margin of the cotyle. The paracotylar foramina, situated in marked depressions, are distinct and close to the lateral margins of the cotyle. In caudal view, the zygantral area is gracile, the condyle is rounded.

Trunk vertebrae ( Fig. 14 E-I)

The vertebrae are characterised by the relatively short and wide vertebral centra, similar feature exhibit representatives of the large colubrids. In lateral view, the neural spine is about two to three times lower than long. The cranial margin of the neural spine overhangs anteriorly, the caudal margin is inclined posteriorly. The interzygapophyseal ridges are mostly well-developed. The lateral foramina occur in wide and sometimes deep depressions, the subcentral ridges are distinct, rounded and often almost straight. The para- and diapophyses are well-separated from each other, the relatively long parapophyseal processes are directed anteriorly. The parapophyses and postero-laterally directed diapophyses are comparative in size. In dorsal view, the zygosphenal lip has prominent lateral lobes, while the median lobe is wide. The prezygapophyseal articular surfaces are roughly oval, the prezygapophyseal processes are long and weakly pointed. Epizygapophyseal spines are missing or under-developed. In ventral view, the subcentral ridges are rounded, the subcentral grooves are distinct (in the posterior trunk vertebrae they are very deep). The subcentral foramina are minute and hardly visible. The anterior keel of the hypapophysis expands in the vicinity of the ventral margin of the cotyle, occasionally it can be developed as distinct subcotylar tubercles. The postzygapophyseal articular surfaces are damaged. In cranial view, the neural arch is often weakly vaulted, the neural canal is subcircular with short lateral sinuses. The parapophyseal processes are separated from the lateral margins of the cotyle by narrow furrows. The paracotylar foramina are situated mostly in deep depressions. The metrical measurements are as follows (n = 10): cl: or = 5.87-7.32; naw: or = 4.37-6.25; cl/naw: or = 1.04-1.49, mean 1.29 + 0.13.

DISCUSSION

The vertebrae belong to large representatives of the family Elapidae . The vertebrae have low ratio cl/naw and the trunk vertebrae have low neural spine which distinguishes Naja sp. 1 from the recent representatives of the genus Naja . Moreover, the lateral foramina occur in deep and wide depressions. Naja sp. 1 resembles N. romani from Kohfidisch (Bachmayer & Szyndlar 1985: fig. 5) in the shape and the length of the prezygapophyseal processes and resembles N. romani from Petersbuch 2 (Szyndlar & Schleich 1993: fig. 7F) in the shape of the zygosphenal lip; in N. depereti the lateral lobes of the zygosphene are under-developed (Bachmayer & Szyndlar 1985). Naja sp. 1 resembles N. iberica in the ratio cl/naw (in N. iberica the vertebrae are relatively narrower than in N. romani [Szyndlar 1985]) and the length of the prezygapophyseal processes; however, the processes in Naja sp. 1 seem to be somewhat longer. Naja sp. 1 differs from Naja romani in the following features: 1) the relatively narrow- er vertebrae in Naja sp. 1; 2) the anterior margin of the neural spine is clearly inclined anteriorly in Naja sp. 1 while in Naja romani it is almost vertical. Concerning the recent representatives of the genus Naja , the Asiatic members of this genus are characterised by the relatively narrower vertebral centres, especially N. sputatrix (ZZSiD 470), in contrast to the African members – N. haje (Linnaeus, 1758) (ZZSiD 491) and N. nigricollis Reinhardt, 1843 (ZZSiD 492).

Figures

FIG. 13. — Naja sp. 1 from the lower/middle (MN 4/5) Miocene of Vieux Collonges; A-D, cervical vertebra (FSL 369144); A, lateral view; B, dorsal view; C, ventral view; D, cranial view; E-I, trunk vertebra (FSL 369178); E, lateral view; F, dorsal view; G, ventral view; H, cranial view; I, caudal view. Scale bars: 2 mm.

FIG. 14. — Elapidae B from the lower/middle (MN 4/5) Miocene of Vieux Collonges, trunk vertebra (FSL 369214); A, lateral view; B, dorsal view; C, ventral view; D, cranial view; E, caudal view. Scale bar: 2 mm.