Plekocheilus (Eurytus) aristaceus (Crosse, 1869)

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

Taxon classification Animalia Stylommatophora Amphibulimidae

Plekocheilus (Eurytus) aristaceus (Crosse, 1869) Fig. 1

Bulimus aristaceus Crosse 1869: 185; Hidalgo 1870: 54, pl. 6 fig. 5; Crosse 1870: 105, pl. 6 fig. 5; Crosse 1871: 318; Pfeiffer 1877: 44; Miller 1878: 182; Paetel 1889: 208.

Eurytus aristaceus ; Pfeiffer and Clessin 1879 [1879-1881]: 227; Cousin 1887: 204.

Bulimulus aristaceus ; Paetel 1889: 221.

Plekocheilus aristaceus ; Pilsbry 1895 [1895-1896]: 88, pl. 4 fig. 4; Pilsbry 1902: xix; Richardson 1995: 302.

Plekocheilus (Eurytus) aristaceus ; Breure 1979: 29; Breure and Borrero 2008: 5.

Type locality.

"Quito, republica Aequatoris".

Type material.

MNCN 15.05/7180, lectotype.

Re-description.

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.

Remarks.

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.