Additional notes on Propeleda platessa (Dall, 1890) and designation of its lectotype (Pelecypoda, Nuculanidae)

While working on a collection of marine molluscs from Surinam a species of Nuculanidae came to my attention that at first could not be identified. It was classified with the genus Propeleda for reasons given in my previous paper (Nijssen-Meyer, 1972: 452). While that paper was in press, I received on loan the type material of Propeleda platessa (Dall), which proved to be identical with the species from Surinam, so that the range of the species is extended from 23°08’S (Rio de Janeiro) to about 07°20’N (off the Surinam coast). Until recently only a few references have been made to Propeleda platessa (Dall, 1890), viz., Lange de Morretes, 1950, Klappenbach & Scarabino, 1969, and Rios, 1970, all listing the original material of Dall. Rios (1970: 250) mentions: “Errata. Plate 50. Instead of Nuculana acuta Conrad read Nuculana platessa (Dall)”. Although Rios lists Dall’s material, he apparently did not examine the syntypes of Propeleda platessa, because his figure on Plate 50 does certainly not depict Nuculana platessa, this already being clear from the shape of the figured shell which does not agree with the shape of the syntypes of Propeleda platessa.