Cerithium miocanariensis 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 : 208

Cerithium miocanariensis Martín-González & Vera-Peláez sp. nov.

Figure 8 A, B, C

1952 Cerithium multigranulatum de Serres. Martel Sangil : p. 118, pl. 47, figs 1, 2.

Type material. Holotype: adult specimen with fragmented shell aperture, medium sized (H: 37.4 mm; W: 18.1 mm), record number TFMCFO-6539. Paratypes: four adult specimens recorded as TFMCFO-6531 (H: 48 mm; W: 19.3 mm); TFMCFO-1620 (H: 38.3 mm; W: 17.7 mm); and TFMCFO-1292 (H: 35.7 mm; W: 15.6 mm).

Other material examined. Thirty-one specimens, two from Lanzarote (TFMCFO-1292, Punta Gorda), nine from Fuerteventura (TFMCFO-6531, TFMCFO-6541, Aljibe de la Cueva; TFMCFO-3721, Punta del Viento; TFMCFO-6539, Playa del Águila) and 20 from Gran Canaria (TFMCFO-1488, TFMCFO-1620, Barranco Seco). Their biometrics and descriptive statistics are displayed in Table 7.

Type locality. Playa del Águila (Fuerteventura, Canary Islands), UTM 28 R 595683 m E 3169313 m N , 12 m asl. The level is composed of c. 40 cm thick beige-colored sandstones. Dated as Tortonian by the gastropod association described above. The paratypes are from Aljibe de la Cueva in Fuerteventura, Barranco Seco in Gran Canaria, and Punta Gorda in Lanzarote .

Etymology. The specific epithet refers to its Miocene assignation and the Canary Islands.

Description. Shell large for the genus (Hmax: 49.7 mm; Wmax: 21.7 mm), solid, and cyrtoconoid in shape, with paucispiral protoconch only visible in a couple of specimens. Teleoconch with six whorls, suture shallow and straight. Penultimate and last whorls rounded, convex in adult specimens. Other whorls have a slightly angular profile and a cord of small pointy nodules. This cord is wider in the first whorls, resembling a varicose rib. In addition, fine cords are present, very close to each other, narrower in first and last whorls, wider in the intermediate ones. These cords are straight and separated by narrow flutes. Axial sculpture consists of weak ribs in the first whorls, very worn in all specimens. Growth lines not observed due to worn shell. Last whorl higher than spire, rounded in appearance, constricted towards the base. Lower half of final whorl has narrow spiral cords, without tubercles. Aperture narrow, labrum totally or partially broken in all specimens examined. Outer lip with abapical narrow sinus and a short, straight, narrow siphonal channel. Columellar lip slightly concave with a thin columellar callus, eroded in most specimens. Color not preserved in any of the specimens.

Remarks. Cerithium miocanariensis sp. nov. is different from fossil and extant Canarian specimens of C. vulgatum Bruguière, 1792 in its less turriculate shell, that is notably wider in the last whorls. The first whorls are proportionally lower and wider than in C. vulgatum and the cords of tubercles on them are wide. This tubercle cord is closer to the abapical suture in this species than in C. vulgatum . In addition, the spiral cords are wider and higher in C. miocanariensis sp. nov. than in C. vulgatum , and are more numerous. The last whorl presents no tubercle cords adapically and the siphonal channel is more elongated than in C. vulgatum . Martel Sangil (1952) reported Cerithium multigranulatum ( Serres, 1829) from the Miocene of the Las Palmas Detritic Formation. This is a species with inflated whorl profile, which differs from C. miocanariensis in having two nodulous cords, one subsutural and another suprasutural. Cerithium miocanariensis sp. nov. only has a cord situated in the lower half of the whorl’s height, with well-developed, thorny nodules in a spiral arrangement.

Rothpletz & Simonelli (1890) and Martel Sangil (1952) cited Cerithium varicosum Brocchi, 1814 for the Las Palmas Detritic formation, but since these authors did not provide figures, their material cannot be compared to Cerithium miocanariensis sp. nov. However, Cerithium varicosum specimens from the Estepona basin have some very fine axial ribs, which are absent in C. miocanariensis sp. nov. In addition, the spiral cords are finer than those in C. miocanariensis sp. nov. Specimens from the Canary Islands which have been assigned to Cerithium varicosum and Cerithium multigranulatum are probably assignable to Cerithium miocanariensis sp. nov., although we cannot state this categorically.

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

Figures

FIGURE 8. Cerithium miocanariensis sp. nov., holotype, H: 37.4 mm; W: 18.1 mm; A. ventral view; B. dorsal view; C. detail of sculpture shell; scale 1 cm. Tectarius isletaensis sp. nov., holotype, H: 5.3 mm; W: 4.2 mm; D. ventral view; scale 0.5 cm. E. dorsal view. Morula mionigra sp. nov., holotype, H: 10.6 mm; W: 7.5 mm; F. frontal view; G. ventral view; H. detail of denticles on outer lip; scale 0.5 cm. Conus fuerteventurensis sp. nov., holotype, H: 27.3 mm; W: 18 mm; I. ventral view; J. dorsal view; K. adapical view; scale 1 cm.