Review of the N. taeniopygus species group from Tanzania
Watters, B. R., B. Nagy, P. D. W. van der Merwe, F. P. D. Cotterill & D. U. Bellstedt. 2019. Review of the Nothobranchius taeniopygus species group from central and western Tanzania with descriptions of five new species and redescription of Nothobranchius taeniopygus (Teleostei: Nothobranchiidae). Ichthyological Exploration of Freshwaters, IEF-1110, pp. 1–41.
Abstract
The Nothobranchius taeniopygus species group from central and western Tanzania is reviewed. Five new species are identified, to raise total species richness to seven. Members of this group are characterized by an anal fin with a slender to broad light medial band and broad black distal band in males.
Nothobranchius taeniopygus is redescribed and the species is characterized by an anal fin with a narrow yellow to white subdistal band; a caudal fin that is light yellow-grey with brown stripes proximally parallel to fin rays, followed by a narrow brown medial band and a narrow yellow to white subdistal band; a postorbital length of 43-46 % HL; and snout to eye end length 54-57 % HL; and its distribution is restricted to the uppermost reaches of the Wembere River system.
Nothobranchius angelae, new species, from the Bubu River system and the Bahi Swamp, as well as the north-western part of the Ruaha River system, is characterized by an anal fin with a slender white medial band; a caudal fin with a narrow dark brown to black medial band, followed by a slender white subdistal band; postorbital length 55-63 % HL; and caudal peduncle length 132-137 % of its depth.
Nothobranchius ottoschmidti, new species, from the Wembere and Manonga river systems, the eastern and north-eastern parts of the Malagarasi system, and the southern Lake Victoria basin, is characterized by a caudal fin with small red-brown spots proximally, a slender semi-translucent grey subdistal band and a narrow irregular dark grey to black distal band; a head width 67-73 % HL; and caudal peduncle length 121-130 % of its depth.
Nothobranchius sonjae, new species, from the Malagarasi River drainage and the Moame River of the Lake Victoria basin, is characterized by a golden-brown to grey stripe on the dorsal scale row between nape and dorsal-fin origin; a head length of 25.8-27.0 % SL; and caudal peduncle length 153-159 % of its depth.
Nothobranchius rungwaensis, new species, from the Rungwa River system, is characterized by an anal fin yellow proximally with a narrow red-brown submedial band, a broad yellow medial band with red to red-brown spots, and a broad black distal band; a head width 54 % HL and 62 % of its depth; interorbital width 38 % HL; postorbital length 46 % HL; snout length 22 % HL; and caudal peduncle length 119 % of its depth.
Nothobranchius skeltoni, new species, from the Lake Victoria basin, is characterized by an anal fin that is grey to red-grey with irregular dark grey spots proximally, followed by a broad dark red to maroon medial band, a narrow light grey subdistal band; a body depth at pelvic-fin origin 26.3-30.0 % SL; suborbital depth 15-22 % HL; caudal peduncle depth 11.8-12.9 % SL; and caudal peduncle length 160-169 as % of its depth.
The species group also includes N. ivanovae. Genetic divergence in partial sequences of the mitochondrial genes, ND2 and COI, and three nuclear genes, Glyt, MyH6 and SNX33, supports the genetic distinction of the five new species and confirms their position, together with N. taeniopygus and N. ivanovae, in the N. taeniopygus species group.
