Atlantica (Canaridiscus) saproxylophaga Alonso, G. Holyoak & Yanes, sp. nov.
Creators: name: Yanes, Yurena
name: Holyoak, Geraldine A.
name: Holyoak, David T.
name: Alonso, Maria R.
name: Ibáñez, Miguel
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Stylommatophora
Gastrodontidae
Atlantica
Atlantica saproxylophaga

description: Atlantica (Canaridiscus) saproxylophaga Alonso, G. Holyoak & Yanes, sp. nov.
Type locality. Montaña Quemada, La Gomera. UTM: 28RBS8312, 1000 m altitude.
Holotype (alcohol specimen): TFMC (MT 0426). Leg. M. Ibáñez, 20 December 1992.
Paratypes. 6 alcohol specimens (AIT) and 5 shells (JSGC), collected between 1983 and 2008 from the Park National of Garajonay (La Gomera).
Etymology. The specific epithet refers to the specimens being found only inside the damp trunks of decaying trees in the laurel forest (laurisilva).
Distribution (Fig. 1). Endemic to La Gomera. It occurs at an altitude of 740–1150 m, in the National Park of Garajonay.
Description. Shell large (Fig. 2 A), fragile, lens shaped, slightly translucent, with numerous scars on the dorsal side, with 6½–7 irregularly convex whorls (almost flat), keeled up to the aperture, slowly and regularly increasing in size; sutures impressed; base excavated with a widely open umbilicus, which reaches nearly 30% of the shell maximum diameter and reveals all the whorls including the nucleus; aperture angular because of the keel, irregularly arched above, ovate below; peristome simple, acute, without parietal callus, parietal and columellar lip terminations widely separated. Shell colour brown, with irregular pale-brown patches above and below. Protoconch smooth, with 1½–2 whorls. Teleoconch almost regularly ribbed above, with about 5 fine radial ribs/mm, smoother and regularly ribbed below. Some dorsal ribs are interrupted, forming small granulations on the early whorls.
Genital system (five specimens dissected). Right ommatophore retractor crosses the distal genital system through a ring formed by penis, vas deferens and vagina (Fig. 3 B–D), open proximally (Fig. 3 C), "bridle" linking the vas deferens to the proximal end of the genital atrium (Fig. 3 D, E). Atrium short (Fig. 3 C, D). Penis tubular, spectacularly long and with many folds in its natural resting position, occupying slightly more than one-half of the body whorl length (Fig. 3 A), but reaching about 100 mm in length when extended (Fig. 3 C). Penis thickest in its proximal part, thinnest in the middle part and intermediate in the distal part; penial cavity occupied by two pilasters, a larger and a smaller (Fig. 3 C). Vas deferens enters the penis through a short and fine duct (Fig. 3 F), close to insertion of penial retractor muscle. Penial retractor long (more than 10 mm), running close to columellar muscle pack (Fig. 3 A) but shorter than the pack muscles and with single attachment to the visceral tegument (Fig. 3 B). Bursa copulatrix small, bursa duct long and very thin, without diverticulum (Fig. 3 C); Albumen gland very short, forked (Fig. 3 G). Hermaphroditic duct large, regularly kinked in the middle part, its distal part little folded and distended into an "ampulla" (Fig. 3 C, G); talon short, apparently lobed (Fig. 3 G).
description: Published as part of Yanes, Yurena, Holyoak, Geraldine A., Holyoak, David T., Alonso, Maria R. & Ibáñez, Miguel, 2011, A new Discidae subgenus and two new species (Gastropoda: Pulmonata) from the Canary Islands, pp. 43-49 in Zootaxa 2911 on page 44, DOI: 10.5281/zenodo.203498