Plekocheilus (Eurytus) nocturnus Pilsbry, 1939

(Figs 16 A–F)

Plekocheilus nocturnus Pilsbry 1939: 3, fig. 5. Type locality: Ecuador, Puyo. Lectotype ANSP 170695 (Baker 1963); Richardson 1995: 317 (references).

Material. Ecuador, Imbabura, Ibarra: DMNH 141641; Napo, Topo: DMNH 76773, DMNH 129338, DMNH 151003); “Napo:” DMNH 141674; Pastaza, Mera: DMNH 141650; Puyo: ANSP, DMNH 141683;?, “ Ecuador:” USNM 532634 (ex Fulton, as P. semipictus); “El Oriente,” leg./1937: USNM 628796 (as P. tricolor semipictus).

Remarks. Although the name P. semipictus has been used for this taxon, this is a clearly distinct species. The upper part of the last whorl is very globose, the lower part is more constricted, thus giving a “humpback” impression.