Plekocheilus (Plekocheilus) cecepeus, Breure, Abraham S. H. & Araujo, Rafael, 2015

Breure, Abraham S. H. & Araujo, Rafael, 2015, A snail in the long tail: a new Plekocheilus species collected by the ' Comision Cientifica del Pacifico' (Mollusca, Gastropoda, Amphibulimidae), ZooKeys 516, pp. 85-93 : 87-90

Taxon classification Animalia Stylommatophora Amphibulimidae

Plekocheilus (Plekocheilus) cecepeus sp. n. Fig. 2

Diagnosis.

A moderately small species of Plekocheilus (Plekocheilus) , characterized by the irregularly shaped, widely spaced, narrowly reddish-brown axial colour streaks, and the spiral series of oblong granules between the axial riblets, becoming a malleate pattern on the dorsal side of the last whorl.

Description.

Shell up to 45.0 mm, 1.76 times as high as wide, imperforate, ovate, sides of spire hardly convex, moderately solid. Colour light chestnut-brown, with irregular, axial streaks of reddish-brown, partly as oblique lines or as zig-zag lightning streaks and partly broken up. Upper whorls paler or denuded of epidermis. Surface somewhat glossy, with moderately strong axial riblets, partly broken up into smaller ones, especially on lower ventral part of last whorl; penultimate whorl with spirally arranged oblong granules in between axial riblets, becoming gradually stronger and forming, on dorsal side of last whorl, a malleated pattern of spirally arranged, broken axial riblets partly irregularly shaped. Protoconch smooth (eroded). Whorls up to 4.9, hardly convex, last whorl 0.94 times shell height, somewhat swollen. Suture well impressed, descending in front and abrubtly ascending behind lip. Aperture elongate-ovate, 2.28 times as long as wide, height 0.72 times shell height. Peristome expanded and reflexed, whitish or pinkish, slightly curved at insertion to parietal wall. Columellar margin curved, above a more or less weak fold entering the aperture; broadly dilated above at the insertion to the parietal wall, which has a thin whitish or translucent, broadly spreading callus.

Dimensions in mm: H 37.8-45.0, D 22.3-25.4, HA 23.5-32.2, WA 11.6-14.8, LW 34.0-42.2, 3.8-4.9 whorls. Holotype H 44.8, D 25.4, HA 32.2, WA 14.1, LW 42.2, 4.8 whorls.

Type locality.

Ecuador, “Quito” (teste Hidalgo 1893: 102). See remarks.

Type material.

MNCN 15.05/60013H, holotype; MNCN 15.05/60013P, five paratypes; MNCN 15.05/7477P, three paratypes.

Comparison with other species.

This new species bears resemblance with Plekocheilus (Plekocheilus) blainvilleanus (Pfeiffer, 1848) from northern Venezuela, but differs in being smaller, the last whorl less malleated, and having the suture abruptly ascending behind the lip. It may also be compared to the Venezuelan Plekocheilus (Plekocheilus) fulminans (Nyst, 1843), from which it differs by having a larger aperture, the lip less thick, and a less pronounced fold in the columella. Finally, it resembles Plekocheilus (Plekocheilus) alticola Haas, 1955 from Venezuelan Guayana, but differs by being slightly larger, and having a less malleated sculpture.

Remarks.

The type locality is unfortunately very imprecise, which was not uncommon with material collected during the 19th century ( Breure and Borrero 2008). Almagro (1866: 81) briefly described the two months the expedition stayed in Quito from the beginning of December 1864 to the beginning of 1865. During that period they made excursions in the province of Imbabura and to the volcans of Antisana, and Pichincha. A detailed list of localities of Ecuadorian material, with collectors and number of specimens can be found in Almagro 1866: 163-164. However, it cannot be excluded that the material was actually colected at a considerable distance from the capital, and it remains to be seen if future collecting may provide more precise localities for this species.

Etymology.

The specific epithet is formed after the abbreviation for the ‘Comisión Científica del Pacífico’ (CCP). Named in honour of the expedition members of this commission, i.e. Patricio María Paz y Membiela (1808-1874), Manuel Almagro (1834-1895), Fernando Amor (1820-1863), Francisco de Paula Martínez y Sáez (1835-1898), Marcos Jiménez de la Espada (1831-1898), Rafael Castro y Ordóñez (1834-1865), and Juan Isern (1825-1866). 150 years ago they returned with many undescribed species and this novelty remained all those years on the shelves. The epithet is used as a noun.