Elapidae, Boie, 1827

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 : 581-582

Elapidae A

Elapidae A – Ivanov 1997a: 134-135, fig. 62.

MATERIAL EXAMINED. — 2 trunk vertebrae ( FSL 369197, FSL 369198).

DESCRIPTION

Trunk vertebrae

In lateral view, the neural spine is very low with vertical margins. The interzygapophyseal ridges are prominently developed, the lateral foramina are situated in deep depressions. The para- and the diapophyses are clearly separated, the diapophysis is strikingly smaller than the parapophysis. The parapophyseal processes are short. The subcentral ridges are strongly developed and arched dorsally. The hypapophysis is very short, its distal tip is situated closely near the proximal margin of the condyle; in the posteriormost vertebrae the hypapophysis can be bifurcated (FSL 369198). The condyle is borne by a short neck. In dorsal view, the cranial margin of the zygosphene has distinct lateral lobes, the strongly damaged median lobe was originally distinct and wide. The prezygapophyseal articular surfaces are obovate, the short prezygapophyseal processes are pointed. Epizygapophyseal spines are missing. In ventral view, both the subcentral ridges and grooves are noticeable developed. The subcentral foramina are shifted anteriorly at the basis of wide hypapophysis. The minute subcotylar tubercles are developed in one vertebra (FSL 369197). The postzygapophyseal articular surfaces are obovate. In cranial view, the neural arch is vaulted, the neural canal is circular with lateral sinuses at the ventral margin; the zygosphenal lip is convex. Distinct nerve foramina may be seen at the bases of the prezygapophyseal processes. The large paracotylar foramina are situated in depressions on either side of the round- ed cotyle.

DISCUSSION

The vertebrae of the morphotype Elapidae A are characterised by the following features: 1) the very small dimensions; 2) the very low neural spine; 3) the vaulted neural arch; 4) short parapophyseal processes directed anteriorly. The vertebrae belong most likely to small representatives of cobras. The morphotype Elapidae A resembles extinct species Micrurus gallicus Rage & Holman, 1984 because of the elongated centra of vertebrae, the shape of the zygosphene and the rela- tively shallow caudal notch. The hypapophysis is directed caudally, however, in M. gallicus the hypapophysis is shorter. The most visible difference is the very low and indistinct neural spine in the morphotype Elapidae A; in the case of M. gallicus the low neural spine is distinctly developed (Szyndlar & Schleich 1993). Moreover, Elapidae A is characterised by shorter prezygapophyseal processes.