Chiridota durbanensis new species and a new record of Neothyonidium arthroprocessum from the east coast of South Africa (Echinodermata: Holothuroidea)

Abstract

Three fragments of a new species, referable to the apodid holothuroid genus Chiridota, and two specimens and 12 fragments of a phyllophorid, referable to Neothyonidium arthroprocessum, first described by the writer from False Bay, Western Cape Province, are here described from shallow water off the Bluff in Durban, KwaZulu-Natal. The new apodid, described as C. durbanensis, appears to be quite close to C. furruginea(Verrill) from the north-west Atlantic waters, differing from it in the apparent absence of wheel papillae, absence of radial muscle deposits and the different form of tentacle deposits. Specimens of N. arthroprocessum are much smaller than the type material and show variations in the number and arrangement of tentacles, number of polian vesicles and the size of the spicules, perhaps indicating geographic and/or age variations. The characteristic U-shaped body wall deposits are here reported, for the first time, to be accompanied by their precursors, flat smooth buttons. The transformation of the latter to the U-shaped deposits is discussed. The occurrence of N. arthroprocessum from the warm KwaZulu-Natal waters is a noteworthy eastward extension of a species originally thought not to extend beyond False Bay, Western Cape Province.