Vipera cf. latastei Boscá, 1878

Marquina-Blasco, Rafael, Fagoaga, Ana, Crespo, Vicente D., Martínez-Ortí, Alberto, Bailon, Salvador, Sánchez-Marco, Antonio, Gracia-Monferrer, Daniel, Santisteban, Carlos de & Ruiz-Sánchez, Francisco Javier, 2023, Squamates, rodents, and birds from Holocene deposits of the Illa Grossa Island (Columbretes Islands, Castellón, Spain): an unexpected diverse assemblage, Comptes Rendus Palevol 22 (18), pp. 409-438 : 418-419

Vipera cf. latastei Boscá, 1878

( Fig. 4)

Vipera latastei Boscá, 1878: 121 (original description of the species). — Boscá 1879: 30.

Vipera berus aspis var. latastei – Camerano 1889: 231.

Vipera latastii [sic] – Boulenger 1896: 484.

Rhinaspis (Latastea) latastei Reuss, 1930: 69 .

Vipera ammodytes latastei – Saint-Girons 1977: 605 (the author pointed out that V. latasti was a lapsus calami, thus he proposed that the correct name is V. latastei ; designation of a lectotype). — ICZN 2017: opinion 2381 (case 3629), confirmation that V. latastei is the correct specific name for the taxon.

MATERIAL EXAMINED. — 15 venom fangs ( COLT-2 and 10 ); 1 left dentary ( COLT-49 ); 8 precaudal vertebrae ( COLT-5, 6, 50 and 52 ); 8 centra of precaudal vertebrae ( COLT-51 ); 1 caudal vertebra ( COLT-53 ).

DESCRIPTION

The fangs are strongly curved ( Fig. 4A). Their anterior surface shows an elongated, slender venom discharge distal orifice, which is long and narrow. The pulp cavity and a canal, with a circular cross-section, can be observed in the teeth. The canal is completely closed, without any groove or suture in the external surface of the teeth.

COLT-49 is a fragment of dentary bone with three dental positions, but only two teeth preserved. The teeth, which are inserted on small alveoli, are conical and curved posteriorly.

The precaudal vertebrae are small-sized (CLmed = 2.76 mm; n = 5; σ = 0.43; CLmin = 2.10 mm; CLmax = 3.21), procoelus and longer than wide. In anterior view, the zygosphene is straight ( Fig. 4B). The cotyle is rounded and large. A pair of large and well-defined paracotylar foramina are present. The articular facets of the prezygapophyseal process is dorsolaterally inclined. In posterior view, the neural arch is dorsoventrally flattened ( Fig. 4C). The condyle is rounded and large. Its diameter is smaller than the neural arch one. In dorsal view, the vertebrae show a trilobated zygosphene, where the central and the lateral ones are of similar size. The neural spine runs along the whole extension of the neural arch. The prezygapophyses are anterolaterally projected, whereas the postzygapophyses are posterolaterally projected. The prezygapophyseal process is short and pointed. In ventral view, the centrum is triangular in shape, wider anteriorly than posteriorly and with not well-defined lateral margins. The subcentral foramina are situated in the anterior part of the centrum and are large and well defined. In lateral view, the neural spine is high ( Fig. 4D). The lateral margins of the neural arch are not well defined. The prezygapophyses are anterolaterally projected, whereas the postzygapophyses are posterolaterally projected. The parapophyseal process is well defined and antero-ventrally projected. The inferior margin is well defined. The centrum is transversally convex. The hypapophysis is broken, but seems to be long and straight. In ventral view, the centrum is triangular in shape. It is wider anteriorly than posteriorly. The lateral margins of the centrum are not well defined. The subcentral foramina are situated in the anterior part of the centrum and are large and well defined. The condyle and the cotyle are large and rounded. In posterior view, the diameter of the condyle is smaller than the diameter of the neural arch. The presence of a pair of haemapophysis indicates that COLT-53 belongs to a caudal vertebra.

REMARKS

The recovered fossils are attributable to Vipera by: the presence of a venom fang of solenoglyph type without any groove or suture in the external surface of the tooth; the presence of a closed venom canal which originated from the dentine floding throughout ontogeny; dorsal vertebrae with hypapophysis, neural arch dorsoventrally depressed, vertebral centrum longer than wide, ventrally convex centrum with diffuse lateral margins, well developed condyle and cotyle, parapophyseal processes present, and the articular surface of the pre and postzygapophyses dorsally inclined ( Szyndlar 1984; Bailon 1991; Bailon et al. 2002; Georgalis et al. 2019a). According to the size of the examined vertebrae (CL: 2.76 mm), the material from Illa Grossa belongs to a “European Viper” (CL <5mm). Within the latest group, there are two complexes that differ in their vertebral morphology: the “ Vipera berus complex” and the “ V. aspis complex” ( Szyndlar & Rage 1999, 2002). Their isolated trunk vertebrae may be distinguished by their shape and size. The vertebrae of the “ V. berus complex” are small, elongated, and provided with low neural spine and hypapophyses, whereas the vertebrae of the “ V. aspis complex” bear more developed hypapophyses and neural spine ( Szyndlar & Rage 1999). In the material from COLT, the hypapophyses are broken but they appear to be straight and well-developed; this trait, together with the presence of a high posterior edge of the neural spine (higher than the centrum in lateral view), allow us to attribute the remains to the “ V. aspis complex”. Unfortunately, the hypapophyses from the COLT fossils are broken, and the posterior edge of the neural spine is preserved only in COLT-5, where it is high (higher than the centrum in lateral view) as in the “ V. aspis complex” members. For morphological, palaeobiogeographical, and biostratigraphical reasons, the species present at the Illa Grossa Island most probably was Vipera latastei . Therefore we propose here an open attribution to this taxon until new fossils can definitively settle this problem. This attribution is more extensively discussed in the section on the identity of the Columbretes snakes below.