Scientists have described five new species of cyprinid from the genus Garra during a study of Afro-Asian species.
Melanie Stiassny of the American Museum of Natural History and Abebe Getahun of Addis Ababa University named the new species in a paper in the latest volume of the Zoological Journal of the Linnean Society.
The five new Garra were discovered in Ethiopia, an area to which four of the fish are believed to be endemic. The species have been named Garra regressus, Garra duobarbis, Garra geba, Garra tana and Garra dembecha.
The new speciesGarra regresus was discovered in the Gerima region on the southern part of Lake Tana in Ethiopia, where it lives near papyrus beds close to the shore.
It is unique among African Garra in possessing a narrow mouth, a regressed rostral cap, a small, acutely pointed head and a fully exposed upper jaw.
Garra duobarbis is unique among African Garra in having a single pair of small maxillary barbels tucked under the chin. It was discovered at Koladiba, about 80km south of Gondar, in the Dirma River, Ethiopia. The type specimens were caught in muddy water near Eucalyptus trees which fringe the banks.
Garra geba comes from the Geba River and was discovered in Tigray, Ethiopia. The land here is highly degraded and there is little cover or vegetation. The type series was caught near a motorway bridge in slow flowing water in a muddy, grass-fringed stream.
Stiassny and Getahun said that Garra geba can be distinguished from other members of the genus by the following combination of characters:
"Intermediate disc development; depressed head and gracile body; between five and nine predorsal scales anterior to dorsal fin; asquamate chest, belly, and postpelvic region; posterior chamber of gas bladder small (13.9"16.2% SL); and intestine short (SL 95.0"102.0% Int.L). disc development; depressed head and gracile body; between five and nine predorsal scales anterior to dorsal fin; asquamate chest, belly, and postpelvic region; posterior chamber of gas bladder small (13.9"16.2% SL); and intestine short (SL 95.0"102.0% Int.L)."
Garra tana was discovered in the southern end of Lake Tana, where it was collected within 25-2000m of the shore in water ranging from 2-14m deep. It lives over mud, sand and rocks and is found alongside Garra regressus and Garra dembeensis.
It has a weakly developed oral disc, lacks scales on the belly and post-pelvic regions and, unlike regressus, has a well-developed rostral cap.
Garra dembecha comes from the Bula River in the Abbay drainage in northern Ethiopia. Some specimens in the type series had previously been misidentified as G. quadrimaculata by other authors.
HabitatsStiassny and Getahun examined over 6000 specimens of Garra collected from over 109 localities from all of the major river basins in Ethiopia.
The authors said that, based on Ethiopian species, the genus occupies and range of habitats from pristine to severely degraded. The fish are found at altitudes from 1500-3000m above sea level in waters of 12-32°C with a pH ranging from 6.1-8.9.
"Although the most frequented habitats are either relatively slow-moving or stagnant pools edged with either long grass or other emergent vegetation, Garra are to be found throughout the
region.
"Nonetheless, in Ethiopia species richness tends to decline from north to south. The rivers of the north-western highlands have the highest species diversity of Garra, whereas the freshwater bodies of the south-eastern Highlands, Rift Valley and coastal plains are relatively depauperate.
"The Abbay (including Lake Tana) and Tekezze basins alone contain 75% of the Ethiopian Garra species, a pattern which is consistent generally with the overall distribution of species
diversity in the country."
The paper also includes an artificial key to aid the identification of the 17 currently described species of African Garra.
For more information see the paper: Stiassny MLJ and A Getahun (2007) - An overview of labeonin relationships and the phylogenetic placement of the Afro-Asian genus Garra Hamilton, 1922 (Teleostei: Cyprinidae), with the description of five new species of Garra from Ethiopia, and a key to all African species. Journal of the Linnean Society, 2007, 150, 41-83.