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| Engraulicypris gariepinus Barnard, 1943 Engraulicypris howesi Riddin, Bills & Villet, 2016 Engraulicypris ngalala Riddin, Bills & Villet, 2016 |
Abstract
The river sardine, Mesobola brevianalis (Boulenger, 1908), is the type species of Mesobola Howes, 1984. Standard phylogenetic analyses of partial sequences of the cytochrome oxidase I gene of individuals from populations across southern Africa that are currently identified as M. brevianalis showed that these populations represent four genetically distinct allopatric lineages. Furthermore, Engraulicypris sardella (Günther, 1868), the type species of Engraulicypris Günther, 1894, was convincingly nested amongst these clades. These findings support synonymisation of Engraulicypris and Mesobola syn. n.; restoration of Engraulicypris gariepinus (Barnard, 1943), stat. rev. for the lower Orange River population; description of two new species, Engraulicypris ngalala sp. n. and Engraulicypris howesi sp. n. from the Rovuma and Kunene river systems, respectively; affirmation of the synonymy of Engraulicypris brevianalis (Boulenger, 1908), comb. n. sensu stricto and Engraulicypris whitei van der Horst, 1934; and restoration of Engraulicypris bredoi Poll, 1945, stat. rev. and Engraulicypris spinifer Bailey & Matthes, 1971, stat. rev. from Mesobola. Discriminant function analysis of a truss network of five traditional morphometric measurements and 21 morphometric measurements that characterised the shape of the fishes was used to seek morphological markers for the genetically distinct populations. Only E. gariepinus was morphometrically distinctive, but live colouration differed between the lineages. Detailed taxonomic descriptions and an identification key for the species are provided.
Keywords: Phylogeography, morphometrics, nomenclature, Mesobola, Engraulicypris, new species, new combinations, new synonym
Engraulicypris
Etymology: Engraulicypris alludes to the anchovy-like form (eggraulis, -eos [eggraulis, -eos]; Greek) of these relatives of the carp (kyprinos [kyprinos]; Greek).
Distribution: Southern and Eastern Africa.
• Engraulicypris brevianalis (Boulenger, 1908), comb. n.
• Engraulicypris gariepinus Barnard, 1943, stat. rev.
Etymology: ‘Gariepinus’ refers to the Gariep, a San name for the Orange River that means ‘Great water’.
• Engraulicypris howesi Riddin, Bills & Villet, sp. n.
Etymology: This species is named in honour of Gordon John Howes (1938-2013), whose studies of the osteology of the Danioninae (Howes 1980, 1984) laid the foundations of their modern classification. The epithet is a genitive noun.
Distribution: Namibia, Angola: Cunene River system.
Type locality: Olushandja Dam at channel outlet (17°25’53’’S 14°38’36’’E), Kunene River System, Namibia.
Biology: Very little is known of the biology of this species. Individuals appear to favour turbid, rocky, river regions where they can gather in pockets of recirculating currents. The holotype and some paratypes were collected in the shallow, turbid Olushandja Dam in the Namibian upper reaches of the system. They feed on drifting invertebrate larvae and adults and plankton.
Engraulicypris ngalala Riddin, Villet & Bills, sp. n.
Etymology: In the Cyao language spoken in the Niassa region of northern Mozambique, the name ‘ngalala’ denotes any, small, compressed, silvery fish, including Mesobola and species of Brycinus Valenciennes, 1850 and Hemigrammopetersius Pellegrin, 1926. The epithet is treated as a nominative singular noun in apposition.
Distribution: Mozambique, Malawi: Rovuma River system and Lake Chiuta.
Type locality: Lucheringo River below rapids at Singa hunting camp (11°48'56"S 36°13'15"E), Mozambique.
Biology: This species is found in ecological conditions very similar to those characteristic of E. gariepinus (Bills 2004). It favours big rivers, gathering in slack, turbid and shallow regions with sandy, rocky or muddy substrates. In Lake Chiuta specimens were caught in reed beds along the margins. The Lake Chiuta and Rovuma River stocks may differ ecologically because Lake Chiuta offers a lacustrine pelagic and benthic prey community (copepods, etc.) that is not found in the Rovuma River channel, where fish would predominantly have access to invertebrate drift.
Megan A. Riddin, I. Roger Bills and Martin H. Villet. 2016. Phylogeographic, Morphometric and Taxonomic Re-evaluation of the River Sardine, Mesobola brevianalis (Boulenger, 1908) (Teleostei, Cyprinidae, Chedrini). ZooKeys. 641; 121-150. DOI: 10.3897/zookeys.641.10434