Description of a new Lake Tanganyikan cichlid fish of the genus Cyprichromis (Perciformes: Cichlidae) with a note on sexual dimorphism

Cyprichromis coloratus, a new cichlid species, is described based on 41 type specimens from the Zambian coast of Lake Tanganyika. It differs from Cyprichromis microlepidotus by having fewer scales in the longitudinal line (41-44 v. 59-70 in C. microlepidotus) and upper lateral line (31-36 v. 47-59), from Cyprichromis leptosoma by more dorsal-fin spines (14-15 v. 11-13 in C. leptosoma) and longitudinal line scales (41-44 v. 38-40), from Cyprichromis pavo by fewer dorsal-fin spines and soft rays (29-31, usually 30, in total v. 30-32, usually 3 1, in C. pavo), and from Cyprichromis zonatus by shallower body depth [24.0-28.5 (26.4 +/- 1.1) % of standard length v. 24.5-30.5 (28.4 +/- 1.3) % in C. zonatus] and smaller eye [eye length 25.2-30.9 (27.2 +/- 1.1) % of head length v. 27.9-33.3 (30.2 +/- 1.2) %]. The new species is also separable from C. microlepidotus, C. pavo and C. zonatus by absence of distinct small spots on the body (v. pearl grey and yellowish small spots along scale rows on body at least in males of C. microlepidotus and C. pavo), its distinct dichromatism (particularly on the caudal fin) between males of the same population (v. dichromatism absent in C. zonatus) and absence of vertical bands (v. three or four distinct vertical bands beneath dorsal fin base in live males of C. zonatus). Cyprichromis coloratus n. sp. also exhibits sexual dimorphism, females having a larger head and males having longer pelvic fin, differences which are discussed in relation to reproductive behaviour. A key to the five species of Cyprichromis is included. A lectotype is designated for Cyprichromis leptosoma. (c) 2006 The Authors Journal compilation (c) 2006 The Fisheries Society of the British Isles.