Dentimargo crassidens Ortega & Gofas 2019, n. sp.

• Main Authors: Ortega, José Rafael, Gofas, Serge
• Format: Text
• Language: unknown
• Published: Zenodo 2019
• Subjects: Biodiversity; Taxonomy; Animalia; Mollusca; Gastropoda; Neogastropoda; Marginellidae; Dentimargo; Dentimargo crassidens; Blanco; Lobos; Ortega; Perez; North East Atlantic; Northeast Atlantic
• Online Access: https://dx.doi.org/10.5281/zenodo.3729422; https://zenodo.org/record/3729422

Dentimargo crassidens n. sp. (Fig. 17 A-E) urn:lsid:zoobank.org:act: 30097341-98F6-40FC-A68B-69B7BCB348C1 TYPE MATERIAL. — Holotype. sh., MNHN-IM-2000-34265. Paratypes . 3 adult sh. and 1 immature spm., MNHN-IM-2000-34266, SEAMOUNT 2 DW130. TYPE LOCALITY. — Off NW Gran Canaria, 28°08.95’N, 15°53.11’W / 28°09.06’N, 15°52.92’W, 655- 660 m. ETYMOLOGY. — From the Latin adjective crassus , thick, and dens , a tooth, alluding to the thick labial denticle. OTHER MATERIAL EXAMINED. — 1 sh., DW128. — 47 sh. (12 immature and 35 in early postlarval stage), DW130. DESCRIPTION Shell small, dirty white, very solid, smooth, consisting of 4 1/2 whorls with an elevated but blunt spire; protoconch 1.4 mm in diameter, consisting of about 1 3/4 whorl, slightly brownish in colour, delimited from teleoconch by a tenuous but definite line. Spire whorls very slightly convex, with a thin but distinct suture. Last whorl representing about 80% of total height. Aperture elongate, narrow, parallel-sided except for a very prominent and broad denticle situated on the inner side of the outer lip, at its upper 1/4 adapically. Outer lip bordered externally by a broad thickened labial varix, slightly receding at its adapical end, forming there a distinct shoulder against the penultimate whorl. There are four columellar plaits, stout with a flattened crest, decreasing in size towards the abapical part of the columella. No columellar callus. Dimensions of holotype: 10.0 mm height × 4.7 mm diameter. REMARKS There are four North-East Atlantic species currently assigned to the genus Dentimargo , diagnosed by having a strong denticle on the adapical part of the outer lip: D. hesperia (Sykes, 1905), D. bojadorensis (Thiele, 1925), D. auratus Espinosa, Ortea & Moro, 2014 and D. giovannii Pérez-Dionis, Espinosa & Ortea, 2014, the latter with a type locality in the Canary Islands (Espinosa et al. 2014). The first was described from deep water off SW Spain and is the most similar, but it is smaller (7-8 mm), stouter, with a distinctly broader aperture, columellar plaits with a more acute crest, and the outer lip is not so thickened. The figure in Sykes (1905) shows a more pointed anterior end and a still less prominent labial denticle than the syntype pictured in Bouchet & Warén (1985), but in any case Sykes described the aperture as “broad”. Dentimargo bojadorensis was described from a depth of 146 m off the mainland African coast. It is smaller, more fusiform without a distinct shoulder at the insertion of the outer lip, which narrows considerably at its adapical termination. The inner labial denticle is also different, situated towards the upper 1/3 of the aperture and more elongate, plait-like. Dentimargo giovannii , described from the bathyal level (607 m) near Isla de Lobos between Fuerteventura and Lanzarote, and D. auratus , described from shallow water (20 m) off Cape Blanco, Mauritania, are both distinguished by their extremely high spire, with the insertion of the outer lip situated about mid-height of the shell (near the upper third in Dentimargo crassidens n. sp.) and also by the characteristically pointed shape of the abapical end (see Espinosa et al. 2014). : Published as part of Ortega, José Rafael & Gofas, Serge, 2019, The unknown bathyal of the Canaries: new species and new records of deep-sea Mollusca, pp. 513-551 in Zoosystema 41 (26) on pages 533-534, DOI: 10.5252/zoosystema2019v41a26, http://zenodo.org/record/3726028 : {"references": ["SYKES E. R. 1905. - Descriptions of new forms of Marginellidae and Pleurotomidae. Proceedings of the Malacological Society of London 6 (6): 315 - 318, pl. 17.", "ESPINOSA J., ORTEA J., PEREZ- DIONIS G. & MORO L. 2014. - Adiciones a la familia Marginellidae (Mollusca: Neogastropoda) en las islas Canarias y Mauritania. Vieraea 42: 19 - 34.", "BOUCHET P. & WAREN A. 1985. - Revision of the Northeast Atlantic bathyal and abyssal Neogastropoda excluding Turridae (Mollusca, Gastropoda). Bollettino Malacologico supplement 1: 121 - 296. https: // doi. org / 10.5962 / bhl. title. 140763"]}