Two new cyprinids described from Malawi

South African scientists Denis Tweddle and Paul Skelton have described two new species of cyprinids from Malawi.

The descriptions of the two new large barbs, ‘Barbus’ seymouri and Labeobarbus nthuwa, are published in the latest issue of Smithiana Bulletin.

Both new species are described from the South Rukuru River, which flows into Lake Malawi.

‘Barbus’ seymouri

This is a moderate-sized (up to 108 mm SL), robust bodied, ‘Barbus’ species with an ossified, serrated last dorsal simple ray, 26-29 lateral line scales, fins tinted pinkish-orange, and a midlateral black stripe that extends through the caudal fin to the fork, but does not extend onto the snout.

Barbus seymouri

'Barbus' seymouri. Picture kindly supplied by Denis Tweddle

It differs from other orange finned, serrated-spined ‘Barbus’ species in the region in the absence of the prominent sheath of enlarged scales at the base of the dorsal fin present in the other species, and in the pattern of pigmentation of the mid-lateral stripe.

According to the authors, “[t]he sites where the species is caught are generally clear, strongly-flowing streams with cover in the form of vegetation and/or rocks.”

This species is named after the late Tony Seymour, in recognition of his many years of service to Malawi not only in Fisheries but also in many other aspects of environmental management and conservation, and in particular for his long-term commitment to supporting Lake Malawi’s fishermen.

The genus name is used with quotation marks because it is thought that the small African barbines traditionally assigned to this genus should not belong to the same group as the true Barbus, which are all European species.

However, no studies have been published which clarifies the true relationships of this group.

Labeobarbus nthuwa
This is a species with parallel-striated scales, a heavily ossified, unserrated, last unbranched dorsal-fin ray, five unbranched dorsal rays in total, and 30–33 lateral line scales.

Labeobarbus nthuwa

Labeobarbus nthuwa. Picture kindly supplied by Denis Tweddle.
It differs from the two Lake Malawi Labeobarbus (L. johnstonii and L. brevicauda) in scale counts and the presence of the bony dorsal spine, from L. marequensis of the Zambezi River and east coastal rivers south to the Phongolo in gill raker counts, caudal peduncle proportions and the presence of the bony dorsal spine, and from L. codringtonii of the Upper Zambezi River in the absence of the high dorsal fin characteristic of that species.

The authors state that “[a]ll sampling sites where the species has been caught were rocky, fast flowing stretches with some deeper pools.” The species is named after the local name of the fish.

In addition to the two new cyprinid species described in this study, the authors also mention other undescribed fish species in the South Rukuru River, which include at least one other ‘Barbus’ species, two species of the amphiliid catfish Zaireichthys.