Two new rift lake cichlids belonging to the genus Neolamprologus have been described from Lake Tanganyika.
The descriptions of the new species, named Neolamprologus walteri and N. chitambwebwai, are published in a paper written by Piet Verburg and Roger Bills in the latest issue of the journal Zootaxa.
Both new species are members of the N. savoryi species complex (also sometimes known as the N. brichardi species complex), which includes ten other species: N. savoryi, N. brichardi, N. pulcher, N. splendens, N. olivaceous, N. gracilis, N. falcicula, N. crassus, N. marunguensis and N. helianthus.
Members of the N. savoryi species complex are characterised by a lunate tail with long filaments.
Neolamprologus walteriThis species is known in Lake Tanganyika from near the border between Burundi and Tanzania in the north to Cape Kabogo in the south.
It can be distinguished from other members of the N. savoryi complex in having a small interorbital width, small preorbital depth, small caudal peduncle depth, absence of markings on the operculum and bars on the body, absence of scales on the occiput, 33"35 scales in the longitudinal series, 2 scale rows between the upper and lower lateral lines, 16 circumpeduncular scales, absence of scales on the paired fins, absence of ctenoid scales on the dorsal and anal fins, absence of spots on scales, presence of cephalic pits, 6"9 gill rakers,
The new species is named after Walter Dieckhoff, who first recognised this as an undescribed species.
It has been known as Neolamprologus walteri in the aquarium literature for the last two decades, but is only formally described now.
Neolamprologus chitamwebwaiThis species, named after Deonatus Chitamwebwa in appreciation of assistance rendered to the authors, is only known with certainty from the Bangwe Peninsula (although it may also be found in the east coast near the centre of the lake).
It differs from other members of the N. savoryi species complex in having a small body, cheek and caudal peduncle depth, less pronounced marking on the dorsal and caudal fins, the absence of markings on the operculum and bars on the body, 13 pectoral fin rays, larger premaxillary pedicel, 8 upper and 6 lower canines, 33"35 scales in the longitudinal series, 2 scale rows between the upper and lower lateral lines, 16 circumpeduncular scales, absence of scales on the paired fins, absence of ctenoid scales on the dorsal and anal fins, absence of spots on scales, presence of cephalic pits, and 6"9 gill rakers.
The two species have very similar ranges, but occupy different microhabitats. According to the authors: ...Neolamprologus walteri lives in large numbers in sheltered areas with rubble substrate whereas N. chitamwebwai occurs in much lower numbers on more exposed parts of the rocky shores, with large boulders, lower sedimentation rates, coarser sediment, and higher visibility...
Besides this difference, N. chitambwebwai also apparently partakes of a more benthic diet according to stable isotope data.
The morphology of the different members of the N. savoryi species group also show differences related to diet.
This suggests that ecological differentiation between closely related sympatric cichlid species and niche partitioning in this group of fishes is more widespread than previously thought.
For more information, see the paper: Verburg, P and R Bills (2007) Two new cichlid species Neolamprologus (Teleostei: Cichlidae), from Lake Tanganyika, East Africa. Zootaxa 1612, pp. 25"44.