Caprella undulata Guilding, 1824, by monotypy.

West Indies, Panama, Colombia, Ecuador, Peru, Bolivia, Brazil, French Guyane, Suriname, Guyana, Venezuela.

Helix pentadina d’Orbigny, 1835, by subsequent designation (Albers 1860: 195).

West Indies (St. Lucia, St. Vincent), Panama, Venezuela, Brazil, Bolivia, Peru, Ecuador, Colombia.

“Quito, republica Aequatoris”.

MNCN 15.05/7180, lectotype.

Shell 2.12 times as high as wide, with nearly covered, rimate perforation, ventricose-ovate, sides of the short spire slightly convex, moderately solid. Colour light chestnut-brown, with irregular blotches of reddish-brown, especially on last whorl which also shows a faint pattern of spiral bands, the interstices about as wide, which is due to the surface sculpture. Upper whorls slightly paler. Surface somewhat shining, finely granulate, entire teleoconch with a faint pattern of spiral lines of dot-like granulation, crossed by irregular longitudinal growth striae, especially on last whorl. Protoconch smooth and polished (eroded). Whorls 4.3, slightly convex, penultimate more convex and last whorl inflated, its height 0.93 total shell height. Suture well impressed, deeply descending in front. Aperture elongate-ovate, whitish inside, 1.80 times as long as wide, height 0.60 times shell height. Peristome hardly expanded, and slightly reflexed, whitish. Columellar margin slightly curved, above narrowly dilated at insertion to parietal wall, which has a thin, whitish callus.

Dimensions in mm: H 48.3, D 22.7, HA 29.1, WA 16.1, LW 44.8, 4.3 whorls.

Figure 1. 

Plekocheilus (Eurytus) aristaceus (Crosse, 1869), lectotype MNCN 15.05/7180 (H = 48.3).

In the MNCN three lots are labelled ‘Bulimus aristaceus Crosse’ which are considered as syntypes. These lots appear not to be conspecific, and only lot MNCN 15.05/7180 is considered as type material of this taxon. As Crosse did not state on how many specimens his description was based, but no material of this species is present in the Paris collection, the sole specimen is now designated lectotype (design. n.) to fixate the taxon. The figure of Crosse (1870) does not entirely adequately represent the current state of the shell as the colour marks may largely have faded away. Crosse (1871) mentioned a variety, collected “Route de Quito à Napo (prof. Orton)”; this would indicate that this species might occur on the eastern slopes of the Cordillera, but we have not seen this material.

West Indies (St. Vincent, Barbados), Venezuela, Ecuador, Colombia.

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.

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.

Figure 2. 

Plekocheilus (Plekocheilus) cecepeus sp. n., A–D holotype MNCN 15.05/60013H (H = 44.8) E paratype MNCN 15.05/60013P (H = 38.8).

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

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

This new species bears resemblance with Plekocheilus (P.) 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 P. (P.) 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 P. (P.) alticola Haas, 1955 from Venezuelan Guayana, but differs by being slightly larger, and having a less malleated sculpture.

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.

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.