Gibbula tindayaensis Martín-González & Vera-Peláez, 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 : 205-207

Gibbula tindayaensis Martín-González & Vera-Peláez sp. nov.

Figure 7 D, E, F

1890 Trochus sp. Rothpletz & Simonelli: p. 707.

Type material. Holotype: complete shell, excellently conserved, of a large adult specimen (A: 41.5 mm; W: 37 mm), with record number TFMCFO-3462. Paratypes: three shells of adult specimens identified as TFMCFO- 3462b (A: 43.9 mm; W: 40.8 mm); TFMCFO-3461 (A: 37.7 mm; W: 29 mm); TFMCFO-3519 (A: 47.6 mm; W: 45.9 mm).

Other material examined. Twenty-eight specimens, all from several outcrops in Fuerteventura (TFMCFO- 3461, TFMCFO-3462, TFMCFO-4647, Bajas Amarillas; TFMCFO-3488, TFMCFO-3496, Agua Ovejas; TFMCFO-3507, TFMCFO-4261, Peñas Blancas; TFMCFO-3543, Caletones Mansos; TFMCFO-3725, TFMCFO- 6582, Punta del Viento; TFMCFO-3824, Laja de Gaspar; TFMCFO-4671, El Corralito; TFMCFO-3519, North of Aguas Verdes; TFMCFO-6579, Barranco de la Cruz). Their biometric data are shown in Table 6.

Type locality. Bajas Amarillas (Fuerteventura, Canary Islands). UTM 28 R 593643 m E 3161892 m N , 10 m asl. The level is composed of dark gray cemented fossiliferous sandstones. Tortonian dating defined by the gastropod association described above. The paratypes are from Bajas Amarillas and North of Aguas Verdes, in western Fuerteventura.

Etymology. The specific epithet derives from Tindaya mountain, a Protected Natural Monument close to Fuerteventura’s western coast, which was of great importance to the aboriginal inhabitants of the island.

Description. Shell unusually large for the genus Gibbula (Hmax: 45.9 mm; Wmax: 59.1 mm), solid, trochiform, slightly wider than high, spire depressed and tiered. Protoconch slightly eroded in the studied material, seemingly paucispiral. Teleoconch consists of five strongly convex whorls, the third and fourth of which are somewhat straightened, while the last is large with a nearly horizontal subsutural ramp. Sutures well marked. Sculpture includes weak spiral cords, more visible on adapical portion of last whorl. Axial sculpture consists of fine prosocline growth lines, more visible in the last whorl. Last whorl rounded, convex with three prominent abapical cords, separated by two deep grooves. These cords are less prominent in juvenile specimens. Aperture subquadrangular with two pronounced notches where the grooves end; outer lip thin and peristome complete. Columellar edge straight, with a pronounced concavity at the parietal edge and a thin columellar callus that covers the umbilicus only slightly in some specimens. Umbilicus wide and deep. Color has not been preserved in any of the specimens; specimens collected at the Bajas Amarillas site are black (probably due to taphonomic alterations) with white patches.

Remarks. This species has been included within the genus Gibbula because of its turbiniform shape with linear growth and large navel. Rothpletz & Simonelli (1890) described Trochus sp. as having two deep flutes in the base and a size similar to that of the specimens of the new species. It is likely that Trochus sp. is conspecific with G. tindayaensis sp. nov.

Gibbula gigantea Lozano-Francisco & Vera-Peláez, 2002 from the lower Pliocene of the Estepona basin differs from Gibbula tindayaensis sp. nov. by having numerous spiral cords, a thick callus on the inner lip and an almost unnoticeable columellar tooth. The three abapical cords distinguish this from other large-sized species such as G. megamagus Monterosato in Cossmann, 1918 from the Pleistocene of Monte Pellegrino (Sicily). These same diagnostic shell features clearly distinguish G. tindayaensis sp. nov. from the other congeneric species present in the Canary Islands, such as G. aurantia Nordsieck, 1975 , G. candei (d´Orbigny, 1840), G. drepanensis ( Brugnone, 1873) , G. magus ( Linnaeus, 1758) , G. racketti ( Payraudeau, 1826) and G. spurca ( Gould, 1856) .

Distribution. Upper Miocene, Tortonian: Fuerteventura; Lanzarote and Gran Canaria ( Betancort Lozano 2012).

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.