A new nematode species, Rhabdochona (Globochona) rasborae sp. n. (Rhabdochonidae), is described from the intestine of the freshwater cyprinid fish (sidestripe rasbora) Rasbora paviana Tirant in the Bangbaimai Subdistrict, Muang District, Surat Thani Province, southern Thailand. It differs from other representatives of the subgenus Globochona Moravec, 1972 which possess eggs provided with lateral swellings in having a spinose formation at the tail tip of both sexes and in some other morphological features, such as the body length of gravid female (8.6-23.7 mm), presence of two-three swellings on the egg, eight anterior prostomal teeth, length ratio of spicules (1 : 5.3-6.7) and arrangement of male genital papillae. This is the third nominal species of Rhabdochona Railliet, 1916 and the second species of the subgenus Globochona reported from fishes in Thailand. The three species of Rhabdochona recently described from fishes in Pakistan, viz. R. annai Kakar, Bilqees et Khan, 2012, R. bifurcatum [sic] Kakar et Bilqees, 2012, and R. pakistanica Kakar, Bilqees et Khan, 2012, are considered to be species inquirendae.
Based on light and scanning electron microscopical studies, three new, one already known and one not identified species of the nematode genus Rhabdochona Railliet, 1916 are reported from the intestine of freshwater fishes in Dzanga-Sangha Protected Areas (Congo River basin), the Central African Republic: Rhabdochona (Rhabdochona) centroafricana sp. n. from Barbus miolepis Boulenger, R. (R.) marcusenii sp. n. from Marcusenius greshoffii (Schilthuis), R. (Globochona) paski Baylis, 1928 from Phenacogrammus aurantiacus (Pellegrin) (new host record), R. (G.) tricuspidata sp. n. from Raiamas christyi (Boulenger) and Rhabdochona (G.) sp. (only females) from Epiplatys multifasciatus (Boulenger). Rhabdochona centroafricana is mainly characterised by the length of the left spicule (333 µm) and the presence of the operculum bearing a conspicuous gelatinous formation on one of egg poles, R. marcusenii by the length of the left spicule (453-486 µm) and the presence of a single broad filament on one egg pole only and R. tricuspidata by the body with marked cuticular ornamentations and deirids branching into three prongs. A key to valid species of Rhabdochona parasitic in fishes of Africa is provided.