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aqua 26(23-4)_Mastacembelus

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Volume 26, Issue 3-4 – 30 November 2020

Tyson R. Roberts: Two new species of the spiny percheel genus Mastacembelus (Synbranchiformes, Mastacembelidae) with low numbers of dorsal fin spines from the Congo basin, pp. 69-76

 

 

 

 

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SINGLE PAPER


Volume 26, Issue 3-4 – 30 November 2020

Tyson R. Roberts: Two new species of the spiny percheel genus Mastacembelus (Synbranchiformes, Mastacembelidae) with low numbers of dorsal fin spines from the Congo basin, pp. 69-76

Abstract

Two new species of African Mastacembelus are described with unusually low counts of dorsal fin spines. Until now the African species of spiny eels with the fewest dorsal fin spines are M. paucispinis Boulenger 1899, from mainstream rapids of the Lower Congo River, with 6-10 dorsal fin spines, well-developed eyes but obsolescent coloration, and M. sexdecimspinus (Roberts and Travers 1986) from high gradient rapids of Cross River, near Widekum, Cameroon, with 15-16 dorsal fin spines and well-developed coloration. The new species are M. ubangipaucispinis from mainstream rapids of the Ubangi River in the Congo basin, with 10 dorsal fin spines and well developed distinctive color pattern (similar to the obsolescent color pattern of M. paucispinis), and M. kadeiensis, from the Kadei River, Congo basin, Central African Republic, with 19 dorsal fin spines and a distinctive color pattern. The rest of African Mastacembelus have 21-40 dorsal fin spines and a different color pattern from the two new species. Mastacembelus ubangipaucispinis shows similarities with M. paucispinis, differing mainly in well-developed (versus poorly developed but otherwise similar) color pattern and in having fewer dorsal fin rays, 101 versus 115-123. Mastacembelus kadeiensis is perhaps most similar to M. sexdecimspinus and somewhat less closely to M. ubangipaucispinis and M. paucispinis. The holotype of Mastacembelus frenatus Boulenger 1901 from Lake Tanganyika reportedly has only 18 dorsal fin spines but coloration unlike M. kadeiensis. A radiograph reveals that it actually has 26 dorsal fin spines.