Napaeus arinagaensis Artiles, Deniz & Martin 2011, n. sp.
Creators: name: Yanes, Yurena
name: Santana, Jesús
name: Artiles, Miguel
name: Deniz, Francisco
name: Martín, Javier
name: Alonso, María R.
name: Ibáñez, Miguel
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Stylommatophora
Enidae
Napaeus
Napaeus arinagaensis

description: Napaeus arinagaensis Artiles, Deniz & Martín, n. sp.   
Figs. 1, 2, 3 N, 7 D–F, 9 A  
 Type locality. North slope of Arinaga Mountain (Gran Canaria; UTM: 28RDR 6182, 180 m altitude).   
 Holotype (Figs. 2, 3 N; empty shell): TFMC (MT 0417). Leg. M. Valido and M. Ibáñez, 9 July 1989.   
 Paratypes. 36 shells collected between 1989 and 2010 from Arinaga Mountain (east of Gran Canaria); deposited in AIT and the following collections: JSGC (12 shells); MAGC (10 shells).   
 Etymology. The specific name derives from its type locality, Arinaga Mountain.   
 Distribution and habitat (Fig. 1). Endemic to Gran Canaria, occupying an area of about 6 km 2 of the Arinaga mountain and its surroundings (southeast of the island), associated with lowland vegetation, within an altitudinal range between 30 and 180 m. We only found empty shells of this species, which is possibly extinct as living specimens were not recorded during the fieldwork since 1989, despite intensive searching.   
 Diagnosis. Shell slender, conic, almost smooth, shiny, with whorls increasing regularly in size. Aperture ovate, rounded at junction of columellar and palatal edges.   
 Description. Shell (Figs. 2, 3 N) dextral, slender (SB/SH index), conic, with whorls increasing regularly in size; 6¾–7¼ convex whorls, deeply marked suture. Body whorl intermediate (BH/SH index), occupying less than ⅔ of the shell surface area (BS/SS index). Protoconch smooth, shiny, with about 1½ whorls. Aperture short and wide (AH/SH and AB/SB indices), ovate, rounded at junction of columellar and palatal edges. Angle (Fig. 2) between columella and upper palatal margin about 117º. Peristome discontinuous, expanded as narrow 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 junction of parietal and palatal margins. Aperture extending laterally beyond penultimate whorl by about 42% (ca 0.8 mm).   
The majority of the shells collected were bleached and whitish, but some of them, including the holotype, retain a part of the original coloration, being uniformly pale brown, without blotches. Shell ornamentation almost smooth (Fig. 9 A), characterised by numerous weak, radial oblique ribs, only a few stronger on the body whorl. The shell has some gloss despite ribs.  
 Comparison with other taxa. The N. arinagaensis shell (Fig. 3 N) is comparable in form and size to five species from Gran Canaria. It is clearly smaller than N. isletae Groh & Ibáñez, 1992 (Fig. 3 P) and larger than N. exilis Henríquez, 1995 (Fig. 3 M), N. myosotis (Webb & Berthelot, 1833) (Fig. 3 L) and N. osoriensis (Wollaston, 1878) (Fig. 3 K). Napaeus arinagaensis is similar in shell size to N. moquinianus (Webb & Berthelot, 1833) (Fig. 3 O), however, the latter has irregular whitish blotches on its shell and the surface areas of the first whorls and the entire shell of N. arinagaensis are smaller than those of N. moquinianus. Napaeus arinagaensis (Fig. 3 N) and N. myosotis (Fig. 3 L) are similar in the degree of convexity of their whorls whereas the other four species have flatter whorls.
description: Published as part of 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), pp. 35-51 in Zootaxa 2901 (1) on page 46, DOI: 10.11646/zootaxa.2901.1.3, http://zenodo.org/record/5284936