Napaeus validoi Ibáñez, Alonso & Martín, 2011

Yanes, Yurena, Santana, Jesús, Artiles, Miguel, Deniz, Francisco, Martín, Javier, Alonso, María R. & Ibáñez, Miguel, 2011, Five new Napaeus species (Gastropoda: Pulmonata: Enidae) from Gran Canaria and El Hierro (Canary Islands), Zootaxa 2901 (1), pp. 35-51 : 46-48

Napaeus validoi Ibáñez, Alonso & Martín , n. sp.

Figs. 1 , 3 F , 7 D–F , 8 B , 9 B

Type locality. Ñameritas (Gran Canaria; UTM: 28RDR3389, 1000 m altitude).

Holotype ( Fig. 3 F ; empty shell): TFMC ( MT 0418 ). Leg. M. Nogales, 10 November 1984.

Paratypes. 14 specimens and 11 shells, collected between 1984 and 2010 from the central-western part of Gran Canaria; deposited in AIT and the JSGC collection (1 shell) .

Etymology. The specific name is dedicated to our friend Manuel Valido, malacologist from Gran Canaria.

Distribution and habitat ( Fig. 1 ). Endemic to Gran Canaria, occupying an area of about 25 km 2 of the Reserva Natural Integral de Inagua, the Monumento Natural del Roque Nublo and their surroundings, associated mainly with pine forest, within an altitudinal range between 950 and 1450 m. Napaeus validoi is a ground dweller; the specimens collected had the shell disguised by a covering of vertic soil (a type of clayey soil), altering its appearance considerably as in other disguised Napaeus species.

Diagnosis. Shell slender, nearly cylindrical, with prominent aperture and wide lip. Epiphallus with epiphallic caecum. Penial appendix shorter than penis and epiphallus combined. Bursa copulatrix duct shorter than diverticulum.

Description. Shell ( Fig. 3 F ) dextral, slender (SB/SH index), nearly cylindrical, with 7–7½ slightly convex whorls. Body whorl intermediate in size (BH/SH index), occupying about 4/7 of the shell surface area (BS/SS index). Protoconch smooth, shiny, with about 1½ whorls. Aperture short and very wide (AH/SH and AB/SB indices), rounded, with elliptical section at palatal side, more curved at the junction of the columellar and palatal margins. Angle ( Fig. 2 ) between columella and upper palatal margin about 114º. Peristome discontinuous, expanded as wide, whitish lip, more developed in lower part of palatal edge and reflected on columellar edge, partly covering umbilical slit. Older specimens with a callosity between peristome edges and a small nodule at the junction of parietal and palatal margins. Aperture extending laterally beyond penultimate whorl by 50% (ca 1.6 mm).

Shell colour brown. Ornamentation characterised by numerous oblique radial ribs, regularly placed on body whorl and sinuous, sometimes interrupted in remainder of teleoconch whorls, forming small protuberances that are irregularly distributed ( Fig. 9 B ).

Genital system ( Fig. 8 B ; two specimens dissected). Atrium very short. Penis about one quarter of length of epiphallus, with two portions. Distal portion tubular, located between atrium and insertion of penial retractor muscle. Proximal portion slightly swollen. Epiphallus tubular, opening distally into penis, two regions defined by presence of epiphallic caecum, distal region slightly longer and more slender than proximal region. Flagellum very short. Penial appendix arising from distal penis portion near genital orifice, shorter than penis and epiphallus combined. Part A 1 of penial appendix not much differentiated from small, globular part A 2, slightly longer than penis. Appendicular retractor muscle inserting laterally in the proximal zone of part A 1, joining penial retractor on diaphragm walls.

Free oviduct longer than vagina. Bursa copulatrix complex with well-developed diverticulum, branching off near proximal end of bursa duct, longer than bursa duct and similarly inflated when accommodating partner’s spermatophore.

Comparison with other taxa. Shell morphology: Napaeus validoi (max. SH = 19.1 mm) has almost the same height but is more slender (SB/SH index = 0.42) than N. interpunctatus ( Wollaston, 1878) (max. SH = 20.0 mm; SB/ SH index = 0.46), which is the biggest Napeus species from Gran Canaria. The N. validoi shell ( Fig. 3 F ) has a form similar to that of N. chrysaloides ( Wollaston, 1878) ( Fig. 3 E ), but is clearly higher, has a stronger ornamentation, and its rounded aperture is nearly twice as large as that of N. chrysaloides .

Genital anatomy: N. validoi is similar to N. venegueraensis and N. chrysaloides , without important differences between them. The apparently greater length of the diverticulum of the bursa copulatrix in N. validoi ( Fig. 8 ) can be attributed to the remains of a spermatophore inside the dissected specimens.

Figures

FIGURE 1. Geographical distribution of the new species.

FIGURE 2. Drawings of the shell of the holotype of Napaeus arinagaensis n. sp., showing the placement of the measurements obtained (in º, 2 mm or mm). α, upper palatal angle (i.e. the angle between the columella and the upper palatal margin of the aperture); AB, aperture breadth; AH, aperture height; AP, aperture perimeter; AS, aperture surface area (plane view); BH, body whorl height (at columella level); BP, body whorl perimeter; BS, body whorl surface area (plane view); FB, first whorls breadth; FH, first whorls height; FP, first whorls perimeter; FS, first whorls surface area (plane view); PB, penultimate whorl breadth; PH, penultimate whorl height; PP, penultimate whorl perimeter; PS, penultimate whorl surface area (plane view); SB, shell breadth; SH, shell height; SP, shell perimeter; SS, shell surface area (plane view); T, distance between columella and periphery of penultimate whorl above aperture; U, highest distance between columella and palatal edge of aperture.

FIGURE 3. Shells of: A. Napaeus josei n. sp., holotype. B. N. nanodes, from Barranco del Agua, Tenerife (AIT). C. N. badiosus, from Barranco de Valle Seco, Tenerife. D. N. venegueraensis n. sp., holotype. E. N. chrysaloides, from Tamadaba, Gran Canaria (AIT). F. N. validoi n. sp., holotype. G. N. obesatus, from Barranco del Pagador, Gran Canaria (AIT). H. N. bajamarensis, holotype (from Yanes et al. 2009). J. N. grohi n. sp., holotype. K. N. osoriensis, from Osorio, Gran Canaria (AIT). L. N. myosotis, from Montaña de Guía, Gran Canaria (AIT). M. N. exilis, from Altos de Gáldar, Gran Canaria (AIT). N. N. arinagaensis n. sp., holotype. O. N. moquinianus, from Brezal del Palmital, Gran Canaria (AIT). P. N. isletae, holotype.

FIGURE 7. Scatter plots of some shell measurements for the new species and the most similar species. AS, aperture surface area (plane view); BS, body whorl surface area (plane view); FS, first whorls surface area (plane view); PS, penultimate whorl surface area (plane view); SB, shell breadth; SH, shell height; SS, shell surface area (plane view). The dimensions are in mm (lengths) or mm2 (surface areas).

FIGURE 8. Genital systems of: A. N. venegueraensis n. sp., paratype from Barranco de Taurito, Gran Canaria (AIT). B. N. validoi n. sp., paratype from Monte de Inagua, Gran Canaria (AIT). A1–A5, parts of the penial appendix; bc, bursa copulatrix; d, diverticulum; dp, distal penis; e, epiphallus; ec, epiphallic caecum; f, flagellum; go, genital orifice; o, free oviduct; par, penial appendix retractor; pp, proximal penis; pr, penis retractor; v, vagina; vd, vas deferens.

FIGURE 9. Details of shell ornamentation of holotypes (penultimate whorl). A. Napaeus arinagaensis n. sp. B. N. validoi n. sp. C. N. grohi n. sp.