Plekocheilus (Plekocheilus) incognitus, Borrero, Francisco J. & Breure, Abraham S. H., 2011

Borrero, Francisco J. & Breure, Abraham S. H., 2011, The Amphibulimidae (Mollusca: Gastropoda: Orthalicoidea) from Colombia and adjacent areas, Zootaxa 3054, pp. 1-59 : 24-25

Plekocheilus (Plekocheilus) incognitus spec.nov.

(Figs 12A, 15N–O)

Diagnosis. Characterized by a moderately large (up to 77.5 mm), solid shell, uniformly brownish colored with an irregular pattern of slightly raised, lighter lines, giving it a blotchy appearance.

Description. Shell up to 77.5 mm, 1.75 times longer than wide, imperforate, elongate-ovate, sides rather convex, solid. Color golden- to chestnut-brown, with an irregular pattern of lighter colored lines, giving the shell a blotchy appearance; upper whorls lighter and eroded. Surface rather shining, with an irregular pattern of low ridges that are slightly raised, partly fused, become elongated and are covered with fine granulation arranged in the direction of the growth striae, especially discernible on upper part of last whorl. Protoconch eroded. Whorls 4.5, the upper whorls hardly convex, the last whorl much more convex; suture well impressed, somewhat crenulated, descending in front. Aperture elongate-ovate, showing the outside coloration, with a whitish border behind the lip, 1.8 times longer than wide, height 0.55 times the total length; peristome thickened and well reflexed, whitish. Columellar margin slightly curved, hardly dilated, slightly receding, entering the aperture with a conspicuous fold. Parietal wall with a well-developed callus, translucent with a white edge.

Dimensions in mm: holotype H 56, D 32, HA 30.5, WA 21, LW 50, 4.5 whorls. Paratype H 77.5, D 44.5, HA 46, WA 25.5, LW 70, 5 whorls.

Type locality. Colombia, Antioquia, Medellín, Corregimiento Santa Elena, Vereda Piedras Blancas [6°18ʹN 75°31ʹW], 2200 m, Parra & Posada leg./ 10.xi.2003.

Type material. Holotype: UAM. Paratype: Antioquia, Jerico [5°47ʹN 75°47ʹW, 1900 m]: USNM 414157/1.

Remarks. In the sculpture of the shell this novelty resembles P. guildingi , from which it differs by (1) having a darker color; (2) being larger (~ 60 vs. ~ 40 mm); (3) having a stronger columellar fold. It also resembles P. appuni , which differs from this new species by (1) having the columella at an angle from the parietal wall; (2) being uniformly colored without the blotchy appearance caused by the irregular pattern of slightly raised lighter colored lines; (3) the less reflexed lip; (4) being sculptured with oblong granulation, arranged in spiral series.

Ecology. Found dead in a Quercus forest.

Etymology. incognitus (Latin) , unknown. Referring to the fact that this large species is found close to a densely populated city, but remained unnoticed for many years. The epithet is used as an adjective.