Thaumastus (Thaumastus) sumaqwayqu, Breure, Abraham S. H. & Avila, Valentin Mogollon, 2016

Breure, Abraham S. H. & Avila, Valentin Mogollon, 2016, Synopsis of Central Andean Orthalicoid land snails (Gastropoda, Stylommatophora), excluding Bulimulidae, ZooKeys 588, pp. 1-199 : 34-36

Taxon classification Animalia Stylommatophora Megaspiridae

Thaumastus (Thaumastus) sumaqwayqu sp. n. Figs 32 A–F, 35, 87B

Diagnosis.

A relatively small species of Thaumastus (Thaumastus) , characterized, when freshly collected, by the deep brown colour on the last whorl, with a golden hue, with two small brown spiral bands on the upper whorls, one of which is subsutural, the lower one becomes peripheral on last whorls, which have on the upper side a zone of axial bands, the interstices twice as broad.

Description.

Shell up to 52.5 mm, 2.0 times as long as wide, imperforate, rather thin, elongate-ovate, with hardly convex sides, with (when fresh) a deep brown colour on the last whorl, with a golden hue, with two small brown spiral bands on the upper whorls, one of which is subsutural, the lower one becomes peripheral on last whorls, which have on the upper side a zone of axial bands, the interstices twice as broad. Protoconch sculptured with fine axial wrinkles, partly bifurcating or anostomsing on lower part of whorl, on the second whorl partly broken up in oblong granules; teleoconch sculptured with incrassate growth striae and very shallow, more or less interrupted, spiral depressions. Whorls up to 5, hardly convex, suture slightly impressed, somewhat crenulate. Aperture narrowly elongate-ovate, pale brown with a whitish lustre inside, 1.6 times longer than wide, 0.5 times the total height, peristome thin and simple, columellar margin slightly curved, receding above, threadlike entering the aperture, parietal callus transparent and thin.

Dimensions in mm.

H 40.5-52.5, D 21.0-25.2, HA 22.2-25.2, WA 14.2-15.7, LW 32.7-40.8, 4.5-5.0 whorls. Holotype H 52.5, D 25.2, HA 25.2, WA 15.7, LW 40.8, 5.0 whorls.

Type locality.

Peru, Dept. Cuzco, 1.6 km W of Aguas Calientes, slope along river, on the ground between plants near rocks, 1985 m (Fig. 87A).

Ecoregion.

Peruvian Yungas [NT0153].

Type material.

RMNH 201636, holotype. RMNH 201637 (1), VMA (3), paratypes. All material S.J. Breure-Dorsman & A.S.H. Breure leg., 12 March 2012.

Additional material.

Peru, Dept. Cuzco, W of Aguas Calientes, FML (5). M.G. Cuezzo & E. Dominguez leg., 7 March 2007.

Comparison with other species.

This new species resembles Thaumastus (Thaumastus) inca ( d’Orbigny, 1835) but differs in being smaller, having the apex more blunt, the peristome not thickened, nor sinuous.

Remarks.

The holotype has lost the outer shell layer on the last whorls during conservation. Also some of the other specimens in the material examined have partially lost this layer.

Etymology.

The specific epithet is formed from the Quechua words sumaq (good, beautiful) and wayqu (ravine), referring to the type locality, which is along the river at the basis of Machu Picchu. The epithet is used as a noun in apposition.