Phorcus burgadoi Martín-González, 2018

Martín-González, Esther, Vera-Peláez, José Luis, Castillo, Carolina & Lozano-Francisco, M. Carmen, 2018, New fossil gastropod species (Mollusca: Gastropoda) from the upper Miocene of the Canary Islands (Spain), Zootaxa 4422 (2), pp. 191-218 : 203-205

Phorcus burgadoi Martín-González sp. nov.

Figure 7 A, B, C

Type material. Holotype: complete, well-preserved shell of a large adult specimen (H: 35.6 mm; W: 34.8 mm), record number TFMCFO-6109. Paratypes: six specimens with record numbers TFMCFO-4623 (H: 15.6 mm; W: 16.6 mm); TFMCFO-6109a (H: 24.9 mm; W: 23 mm); TFMCFO-6109b (H: 24.7 mm; W: 23.9 mm); TFMCFO- 6109c (H: 35.6 mm; W: 27.9 mm); TFMCFO-3726 (H: 31.8 mm; W: 30.3 mm); TFMCFO-3780 (H: 30.5 mm; W: 28.2 mm).

Other material examined. Overall, 45 specimens, two from Lanzarote (TFMCFO-1835, Barranco de las Pilas), and 43 from Fuerteventura (TFMCFO-3420, Morrete de los Castrillos; TFMCFO-3443, Acantilados de Aldiana; TFMCFO-3462, TFMCFO-3707, TFMCFO-4623, TFMCFO-6109, TFMCFO-6406, Bajas Amarillas; TFMCFO-3465, TFMCFO-6407, TFMCFO-6541, Playa del Águila; TFMCFO-3726, Punta del Viento; TFMCFO- 3743, Majada Blanca; TFMCFO-3752, Barranco de Esquinzo; TFMCFO-4158, Gran Valle; TFMCFO-3780, TFMCFO-6533, TFMCFO-6583, TFMCFO-6584, Aljibe de la Cueva). Table 5 contains the descriptive biometrics and statistics for the species.

Type locality. Bajas Amarillas ( Fuerteventura , Canary Islands). UTM 28 R 593643 m E 3161892 m N , 10 m asl. The level is composed of poorly cemented, dark gray biogenic sandstones. Dated as Tortonian by the gastropod association described above. The paratypes are from the same type locality, as well as from Punta del Viento and Aljibe de la Cueva, in Fuerteventura.

Etymology. The specific epithet refers to the common name given in the Canary Islands to the species in this genus, burgado.

Description. Shell large for the genus (Hmax: 35.6 mm; Wmax: 34.8 mm), robust, trochiform, of equal height and width, with an elevated conical spire. Protoconch paucispiral, slightly eroded. Teleoconch consists of five convex whorls with a straight, linear and superficial suture, and a very prominent ramp. Superficial sculpture lacking in the adult individuals, except for the fine prosocline and opisthocyrt growth lines. In juvenile shells, very attenuated, longitudinal cords on the penultimate whorl. Suture line on last whorl is slightly convex at its end. Base evenly rounded, non-umbilicate. Aperture holostomatous with rounded, unthickened labrum. Short thin callus ending in a single blunt tooth at the columellar edge. Color not preserved; the holotype is black, probably due to taphonomic disturbances.

Remarks. Phorcus burgadoi sp. nov. has not been described in previous works on the Canarian Neogene, despite its considerable size. The genus Phorcus is represented in the Canary Islands by two species, P. sauciatus (Koch in Philippi, 1845) and P. atratus ( Wood, 1828) , which are clearly different from the new taxon because of their smaller size and general shape. Phorcus burgadoi sp. nov. has a higher spire and a more rounded last whorl than P. sauciatus and P. atratus has a stepped shape with straighter and less globular whorls.

Phorcus burgadoi sp. nov. presents some characteristics very similar to those of P. lineatus (da Costa, 1778). They differ in the aperture, which is slightly more closed in P. lineatus , also presenting a slight point in the collumelar tooth of adult specimens, and P. burgadoi sp. nov. has a higher spire. Phorcus turbinatus ( Born, 1778) differs from Phorcus burgadoi sp. nov. by having a higher conical spire and a subquadrangular. The same features distinguish the new species from P. articulatus ( Lamarck, 1822) . Phorcus articulatus also differs in having an ornament of spiral cords separated by fine flutings. Phorcus (Trochocochlea) miocaenica ( Mayer, 1858) from the French Atlantic Miocene differs from Phorcus burgadoi sp. nov. by having an ornament of spiral cords.

Distribution. Upper Miocene, Tortonian: Fuerteventura, Lanzarote and Gran Canaria.

Figures

FIGURE 7. Osilinus burgadoi sp. nov., holotype, H: 35.6 mm; W: 34.8 mm; A. ventral view; B. dorsal view; C. abapical view. Gibbula tindayaensis sp. nov., holotype, H: 37 mm; W: 41.6 mm; D. ventral view; E. dorsal view; F. abapical view; g. ventral view. Jujubinus ajachaensis sp. nov., holotype, H: 23.3 mm; W: 17.8 mm; G. ventral view; H. dorsal view; I. detail of prosocyrt growth lines. Scale 2 cm.