Mastacembelus is a genus of many species of spiny eel fish from the family Mastacembelidae. They are native to Africa ( species) and Asia (c. 15 species). Most are found in rivers and associated systems (even in rapids), but there are also species in other freshwater habitats and a particularly rich radiation is found in the Lake Tanganyika basin with 15 species (14 endemic). A few species can even occur in brackish water.

Appearance

The size and pattern varies greatly depending on the exact species of Mastacembelus. The smallest are M. latens and M. simba, which only reach a maximum total length of . At up to , the largest of both the family and this genus is M. erythrotaenia. M. erythrotaenia, often known as the fire eel, is blackish with an orange-red pattern, and it is a popular aquarium fish. Otherwise species in this genus are typically brownish and often have a spotted, speckled or mottled pattern, either in another brown hue, grayish or yellowish. This pattern is reflected in the common name of another species sometimes kept in aquariums, the zig-zag eel M. armatus (alternatively called the tire track eel, a name otherwise used for M. favus). A few others also occasionally appear in the aquarium trade, and some are considered good food fish and eaten locally. M aviceps, M. brichardi, M. crassus and M. latens are found in dark, deep parts of the Congo River and sometimes shallower among rocks. These four species have reduced eyes and are all pinkish-white in color (non-pigmented), similar to cavefish.

Taxonomy In an evaluation of the Mastacembelidae in 2005, the genera Caecomastacembelus and Aethiomastacembelus (formerly used for the African species) were placed in synonymy with Mastacembelus.

Species

According to FishBase, there are currently 63 recognized species in this genus. Five additional species (marked with a star* in the list) are recognized by Catalog of Fishes.

Mastacembelus alboguttatus Boulenger, 1893 Mastacembelus albomaculatus Poll, 1953 Mastacembelus ansorgii Boulenger, 1905 Mastacembelus apectoralis K. J. Brown, Britz, I. R. Bills, Rüber & J. J. Day, 2011 Mastacembelus armatus (Lacépède, 1800) (Zig zag eel) Mastacembelus aviceps T. R. Roberts & D. J. Stewart, 1976 Mastacembelus batesii* Boulenger, 1911 Mastacembelus brachyrhinus Boulenger, 1899 Mastacembelus brichardi Poll, (1958) (Blind spiny eel) Mastacembelus catchpolei Fowler, 1936 Mastacembelus congicus Boulenger, 1896 Mastacembelus crassus T. R. Roberts & D. J. Stewart, 1976 Mastacembelus cryptacanthus Günther, 1867 Mastacembelus cunningtoni Boulenger, 1906 Mastacembelus dayi Boulenger, 1912 – junior synonym of M. alboguttatus according to Catalog of Fishes Mastacembelus decorsei Pellegrin, 1919

Mastacembelus dictyon Britz & Kottelat, 2025

Mastacembelus dienbienensis V. H. Nguyễn & H. D. Nguyễn, 2005 – belongs in genus Sinobdella according to Catalog of Fishes Mastacembelus ellipsifer Boulenger, 1899 Mastacembelus erythrotaenia Bleeker, 1850 (Fire eel) Mastacembelus favus Hora, 1924 (Tire track eel) Mastacembelus flavidus Matthes, 1962 Mastacembelus flavomarginatus* Boulenger, 1898 Mastacembelus frenatus Boulenger, 1901 (Longtail spiny eel) Mastacembelus goro* Boulenger, 1902 Mastacembelus greshoffi Boulenger, 1901 Mastacembelus kadeiensis Roberts, 2020 Mastacembelus kakrimensis Vreven & Teugels, 2005 Mastacembelus latens T. R. Roberts & D. J. Stewart, 1976 Mastacembelus liberiensis Boulenger, 1898 Mastacembelus loennbergii Boulenger, 1898 Mastacembelus malabaricus* Jerdon, 1849 Mastacembelus marchei Sauvage, 1879 Mastacembelus mastacembelus (J. Banks & Solander, 1794) Mastacembelus micropectus Matthes, 1962 Mastacembelus moorii Boulenger, 1898 Mastacembelus niger Sauvage, 1879 Mastacembelus nigromarginatus Boulenger, 1898 Mastacembelus notophthalmus T. R. Roberts, 1989 Mastacembelus oatesii Boulenger, 1893 Mastacembelus ophidium Günther, 1894 Mastacembelus pani* Endruweit, 2024 Mastacembelus pantherinus Britz, 2007 Mastacembelus paucispinis Boulenger, 1899 Mastacembelus plagiostomus Matthes, 1962 Mastacembelus platysoma Poll & Matthes, 1962 Mastacembelus polli Vreven, 2005 Mastacembelus praensis (Travers, 1992) Mastacembelus reygeli Vreven & Snoeks, 2009 Mastacembelus robertsi (Vreven & Teugels, 1996) Mastacembelus sanagali Thys van den Audenaerde, 1972 Mastacembelus seiteri Thys van den Audenaerde, 1972 Mastacembelus sexdecimspinus (T. R. Roberts & Travers, 1986) Mastacembelus shiloangoensis (Vreven, 2004) Mastacembelus shiranus Günther, 1896 (Malawi spiny eel) Mastacembelus simbi Vreven & Stiassny, 2009 Mastacembelus strigiventus W. Zhou & L. P. Yang, 2011 Mastacembelus taiaensis (Travers, 1992) Mastacembelus tanganicae Günther, 1894 Mastacembelus thacbaensis V. H. Nguyễn & H. D. Nguyễn, 2005 – junior synonym of M. undulatus according to Catalog of Fishes Mastacembelus tinwini Britz, 2007 Mastacembelus traversi (Vreven & Teugels, 1997) Mastacembelus triolobus W. Zhou & L. P. Yang, 2011 Mastacembelus trispinosus Steindachner, 1911 Mastacembelus truttoides* Endruweit, 2024 Mastacembelus ubangipaucispinis Roberts, 2020 Mastacembelus undulatus (McClelland, 1844) Mastacembelus unicolor G. Cuvier, 1832 Mastacembelus vanderwaali P. H. Skelton, 1976 (Ocellated spiny eel) Mastacembelus zebratus Matthes, 1962

References