Patella tintina 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 : 194-197

Patella tintina Martín-González & Vera-Peláez sp. nov.

Figure 5 A, B, C

1976 Patella ambroggii Lecointre. Meco : p. 88.

2001 Patella cf. caerulea Linnaeus. Martín-González et al. : p. 52.

2001 Patella caerulea Linnaeus. Castillo et al. : p. 68.

2008 Patella ambroggii Lecointre. Meco et al. : p. 80, fig. 2.11.

2012 Patella ambroggii Lecointre. Betancort Lozano : p. 97, plate 6, figs. 4, 4a.

2015 Patella ambroggii Lecointre. Meco et al. : p. 65, appendix 2, figs. a, b, c, d, g.

Type material. Holotype: adult specimen, with broken apex, large size (L: 100.6 mm; W: 85.2 mm and H: 50.1 mm), record number TFMCFO-3438/1. Paratypes: four well-preserved specimens, TFMCFO- 3535 (L: 78.6 mm; A: 76.5 mm; H: 25.7 mm); TFMCFO-4601 (L: 52.7 mm; W: 40.9 mm; H: 12.6 mm); TFMCFO-4 608 (L: 99 mm; W: 97.2 mm), and TFMCFO-6107 (L: 42.9 mm; W: 33.8 mm; H: 12.1 mm).

Other material examined. Three more specimens from Lanzarote, with numbers TFMCFO-3836, Punta Gorda and TFMCFO-6483, Punta Garajao; and 25 more from Fuerteventura (TFMCFO-3438, North of Agua Liques; TFMCFO-3718, Punta del Viento; TFMCFO-4593, Fuente Blanca; TFMCFO-4594, Barranco Gavioto; TFMCFO-4606, Playa del Valle; TFMCFO-4603, TFMCFO-5991, TFMCFO-6404, Bajas Amarillas; TFMCFO- 5992, Caletones Mansos; TFMCFO-6107, Aljibe de la Cueva; and TFMCFO-6578, Barranco de la Cruz). Biometric data for this material are shown in Table 1.

Type locality. North of Agua Liques ( Fuerteventura , Canary Islands); UTM: 28 R 573615 m E 3118639 m N , 10 m asl. Sandstone deposit, approximately 50 cm in thickness. Tortonian dating defined by the gastropod assemblage described in the geological and geographic context section above. The paratypes are from the localities: Caletones Mansos (TFMCFO-3535), Barranco León (TFMCFO-4608), Punta de Leonardo (TFMCFO- 4601) and Aljibe de la Cueva (TFMCFO-6107), all in Fuerteventura.

Etymology. The name tintina refers to the metallic sound produced by this limpet shell when struck.

Description. Large-sized shell (Lmax: 112 mm; Wmax: 97.2 mm; Hmax: 51.4 mm), fragile, with thinner section in the apical region and thicker towards the base. Patelliform shape, with conical cap shape in adult phases, more flattened in juveniles. Shell base oval, wider in the posterior region than the anterior. Apex situated further towards the anterior region at nearly 2/3 from the posterior edge. Sculpture consists of six wide main ribs interspersed with a variable number of secondary and tertiary ribs in the anterior region; these become wider during ontogeny. In the posterior region, there are four strongly protruding main ribs, and a variable number of secondary radial ribs placed between the former. Main ribs have a rounded blunt profile. Intercostal spaces between posterior ribs are twice as wide as those in the anterior region, where the two central ribs lie very close to each other. In juvenile forms, the shell surface is covered with scales arranged radially, which are more clearly defined on the secondary ribs and disappear during ontogeny. Growth lines are clearly visible towards the lower middle part of the shell, well-defined and slightly sinuous, in some cases forming darker, circular bands seen also on the ventral side. Shell edge is sinuous and star-shaped. Mantle impression is not visibly apparent in any of the specimens, but marked in internal molds, being large, oval and open at one end, and located close to the base. Color is not preserved.

Remarks. The new taxon has features resembling those of Patella ambroggii Lecointre, 1952 from the Moroccan Pliocene as illustrated by Lecointre (1952). Therefore, several workers identified material from Neogene deposits of the Canary Islands as Patella ambroggii . After consulting photograps of the holotype of P. ambroggii ( Fig. 6 ) deposited at the Muséum national d´Histoire naturelle in Paris, with record number R10111, Patella tintina sp. nov. can be distinguished from P. ambroggii by having more and more densely arranged primary ribs. The base of P. ambroggii is more elongated and rippled, not fitting the pattern of four large, separate ribs in posterior position observed in the Canary species. In contrast to Patella tintina sp. nov., P. ambroggii has a secondary rib between the ribs. Moreover, growth lines on the shell surface are more pronounces in P. ambroggii and form concentric crests. Patella tintina sp. nov. is higher and more conical, with blunter ribs, which give the shell a rounded appearance. The apex is more posteriorly located in the Patella tintina than in P. ambroggii .

Patella tintina sp. nov. differs in size and shell morphology from other smaller species from the Miocene of the Rhone valley such as P. delphinensis Fontannes, 1876 and P. vindascina Fontannes, 1876 ( Fontannes 1882, pl. 1, figs 9–10). When compared to a juvenile form of P. crassicosta Rovasenda, 1897 (in Sacco 1897) from the middle Miocene of the Piedmont-Liguria basin (refigured in plate 3, fig. 5 of Forli et al. 2004), the juvenile Patella tintina sp. nov. can be distinguished by the posterior layout of its main ribs and the more triangular shell shape. Patella alessia Forli, 2004 , a Mediterranean Pliocene species, can be separated from P. tintina sp. nov. by its greater number of main ribs, its lower height and its more star-shaped basal profile.

The large size of P. tintina sp. nov. and its number and arrangement of ribs distinguish it from the three species of the Patellidae currently living in the Canary Islands: Patella crenata d'Orbigny, 1840 , P. ulyssiponensis Gmelin, 1791 and P. piperata Gould, 1846 . The large South African limpets Cymbula oculus ( Born, 1778) and Cymbula granatina ( Linnaeus, 1758) differ from Patella tintina sp. nov. by having a finer and denser ribbing and a different rib layout on their anterior margin. The South African species also differ in their central apex location. Patella tintina sp. nov. resembles the South African Scutellastra longicosta ( Lamarck, 1819) in its star-shaped margin and in having wide ribs, but the latter can be distinguished by its completely star-shaped aspect and different layout of the radial ribs, with four very wide and long ribs towards the posterior region, and three towards the anterior end. Patella caerulea Linnaeus, 1758 , is much smaller and very flat, differing notably in its ornamentation pattern.

Distribution. Upper Miocene, Tortonian: Fuerteventura and Lanzarote ( Betancort Lozano 2012); Gran Canaria ( Betancort Lozano 2012; Meco et al. 2015).

Figures

FIGURE 5. Patella tintina sp. nov., holotype, L: 100.6 mm; W: 85.2 mm; H: 50.1 mm; A. dorsal view; B. ventral view; C. lateral view. Patella maxoratensis sp. nov., holotype L: 93.6 mm; W: 80.5 mm; H: 42.9 mm; D. dorsal view; E. ventral view; F. lateral view. P. mahamensis sp. nov., holotype, L: 34.7 mm; W: 25.1 mm; H: 11.5 mm; G. dorsal view; H. ventral view.; I. lateral view. Scale 2 cm.

FIGURE 6. Patella ambroggii Lecointre, 1952, holotype (MNHN R10111) deposited at the Muséum national d´Histoire naturelle in Paris.