The Identity of Derocheilocaris Remanei Katesae (Mystacocarida) From South Africa

Abstract

Derocheilocaris remanei katesae was described from Durban on the east coast of South Africa by Noodt (1954). He distinguished this subspecies on the basis of the shape of the anterior portion of the cephalon, the spines and seta of the anal operculum and the body shape. The work of Hessler ( 1972 ) on African mystacoca rids brought to light the extreme conservativeness of this subclass and the minute nature of differences sufficient to warrant species status. Forms from Angola and South West Africa, considered by Noodt to be D. remanei, were shown by Hessler to be distinct species and named D. angolensis and D. delamarei respectively. D. r. katesae thus became separated from the type D. remanei by at least two species and nearly 1000 km of coastline. A further species was then recorded from Algoa Bay on the south-eastern corner of Africa (McLachlan & Grindley, 1974) and named D. algoensis. At the time it was not certain whether D. r. katesae and D. algoensis were the same species or whether D. r. katesae was distinct and warranted species status. Noodt's (1954) description of D. r. katesae was not sufficiently detailed to decide this. Now as the result of a series of collections along the east coast of South Africa both north and south of Durban it is possible to clarify this. All specimens examined from these east coast collections are identical to D. algoensis. Three points of difference between Noodt's (1954) description and D. algoensis, namely (1) the antero-medial notch of antennulary portion of cephalon, (2) the constriction separating antennulary portion of cephalon from the rest of the cephalon and (3) the acute process on the supra anal process (anal operculum), were checked. In all cases these appeared as described for D. algoensis, namely (1) a U-shaped anteromedial notch in the cephalon, (2) the constriction in the cephalon had a distinct notch and (3) the supra anal process had two acute processes, a short stout vertral one and a slender, longer dorsal one. It must thus be concluded that D. r. katesae and D. algoensis are conspecific and the small differences in Noodt's description were due to distorted specimens. It is therefore suggested that D. r. katesae Noodt, 1954 be considered a senior synonym of D. algoensis McLachlan & Grindley, 1974. The recorded range of D. katesae is now extended from Algoa Bay up the east coast of South Africa to Sordwana Bay near the Mozambique border. REFERENCES