Napaeus tafadaensis Yanes, 2009

Yanes, Yurena, Martín, Javier, Moro, Leopoldo, Alonso, María R. & Ibáñez, Miguel, 2009, On the relationships of the genus Napaeus (Gastropoda: Pulmonata: Enidae) with the descriptions of four new species from the Canary Islands, Journal of Natural History 43 (35 - 36), pp. 2179-2207 : 2195-2200

publication ID	https://doi.org/ 10.1080/00222930903094621
persistent identifier	https://treatment.plazi.org/id/4014878B-4565-7932-40D0-8030FE39FB98
treatment provided by	Felipe
scientific name	Napaeus tafadaensis Yanes
status	sp. nov.

Treatment

Napaeus tafadaensis Yanes View in CoL sp. nov.

Type material

Holotype ( Figures 3N View Figure 3 , 7B View Figure 7 ): TFMC ( MT 0398 ). Type locality: Montaña Tafada, Anaga massif (Tenerife; UTM coordinates: 28 RCS8761 View Materials ; 600 m altitude). Leg. M. Ibáñez, 6 April 1991.

Paratypes: 8 specimens and 11 shells, collected between 1991 and 2008, from the northeast of Tenerife ( UTM coordinates: 28 RCS7859 View Materials , 28 View Materials RCS8356 View Materials and 28 RCS8761 View Materials ), deposited in CML (one shell), TFMC ( MT 0134 /2) and AIT .

Etymology

The specific name derives from that of the type locality.

Geographic range and habitat Ground dweller endemic to Tenerife, present in about 25 km 2 area along the north

and south facing slopes of the Anaga massif (northeast of the island), associated with lowland vegetation and some subtropical scrub, ranging in altitude between 140 and 600 m ( Figure 1B View Figure 1 ).

Diagnosis

Shell elongated oval, weakly ornamented, sometimes with an irregular growth mode, tan brown coloured, with first whorls slightly darker than the rest. Epiphallus with a well-developed epiphallar caecum. Bursa copulatrix duct without diverticulum.

Description

Two morphotypes of the species displayed small but clear conchological differences while the genital system remained the same.

Typical form ( Figure 3N View Figure 3 ): shell obese (SB/SH index), elongated oval, coneshaped above, 6¼–6½ convex whorls, deeply marked suture ( Figure 7B View Figure 7 ). Body whorl large (BH/SH index), protoconch weakly striated with 1½–1¾ whorls. Aperture long, wide (AH/SH and AB/SB indices, respectively), elliptical section at palatal side, slightly angular at union of columellar and palatal edges. Upper palatal side forms angle slightly greater than 90º with parietal side, aperture juts out considerably from body whorl beginning. Whitish discontinuous peristome expanded as lip, more developed in lower part of palatal edge, reflected in columellar edge, where it partially covers umbilical slit. Older specimens with callosity between peristome edges, nodule at union of parietal–palatal area.

Second morphotype, “irregular” ( Figure 3O View Figure 3 ): shell with irregular growth mode, body whorl and palatal side of aperture flatter, shell smaller (with about six whorls only). Morphotype found in two lower localities (140 and 350 m altitude, respectively).

Shell colour tan brown, first whorls slightly darker than rest. Ornamentation characterized by weak, radial oblique ribs, more-or-less regular on almost all shell ( Figures 7B View Figure 7 , 10B View Figure 10 ). Shell shiny despite ribs. At columellar zone of body whorl, ribs sinuous, irregularly undulating, several ribs interrupted forming granules ( Figure 10C View Figure 10 ).

Genital system ( Figure 11A View Figure 11 ; four specimens dissected of typical form, three of “irregular” morphotype). Atrium very short. Penis mainly tubular, similar in length to epiphallus, four times longer than A 1 portion of penial appendix. Penis with three portions; distal portion located between atrium and insertion of penial retractor muscle; slender, tubular, intermediate portion slightly longer than each of the others; swollen, proximal portion with small penial papilla and inner thick, ring-shaped folds. Epiphallus tubular, opening distally on penis, with two regions defined by presence of well-developed caecum, for moulding and initial accommodation of spermatophoral spur-like hook. Proximal region widened, slender distally, tubular. Flagellum very short. Vas deferens opens laterally on proximal end of epiphallus. Penial appendix arising near distal end of penis, slightly longer than penis and epiphallus together, and shorter than that of other Napaeus species. Male genital system with two slender retractor muscles, penial and appendicular, inserting closely, but not fused, on diaphragm walls. Penial muscle inserts between distal and intermediate penis portions, appendicular muscle inserts laterally near proximal top of penial appendix part A 1.

Free oviduct longer than vagina. Bursa copulatrix duct without diverticulum. Bursa duct short, less than half of penial appendix length.

Remarks

Shell morphology. The shell of N. tafadaensis sp. nov. ( Figure 3N, O View Figure 3 ) is comparable in dimensions with those of N. tabidus ( Figure 3M View Figure 3 ) and N. badiosus ( Figure 3P View Figure 3 ), but clearly more slender than that of N. badiosus ( Figure 6E View Figure 6 ). N. tafadaensis has similar ornamentation to N. badiosus ( Figures 10B and 10F View Figure 10 , respectively) while the radial oblique ribs of the body whorl are discontinuous and granulated in N. tabidus ( Figure 12D View Figure 12 ). N. tabidus shows variability in shell dimensions but normally has a bigger aperture than N. tafadaensis ( Figure 6F View Figure 6 ). The other species of the N. baeticatus group are clearly bigger, while the species of the N. nanodes group are smaller and have prominent radial oblique striation. Lastly, the species of the N. variatus group are evidently more slender.

Genital system anatomy. The epiphallar caecum is present in N. tabidus ( Odhner 1932: 62, figure 21) and N. tafadaensis , and lacking in N. badiosus ( Krause 1895: pl. 1, figure 9). The bursa duct of N. tafadaensis and N. badiosus lacks a diverticulum; this is present in N. tabidus .