Dujardinascaris sp.

Moravec, František & Jirků, Miloslav, 2017, Some nematodes from freshwater fishes in central Africa, Folia Parasitologica (033) 64, pp. 1-39 : 31

Dujardinascaris sp. third-stage larva

Fig. 26

Description (one specimen). Body fusiform, whitish, with finely transversely striated cuticle; length of body 10.1 mm, maximum width 381. Cephalic end rounded, anlagen of lips or larval tooth indistinct in lateral view ( Fig. 26A ). Lateral alae absent. Oesophagus narrow, 1.2 mm long, 57 wide. Ventriculus oval, 87 long and 54 wide. Nerve ring 258 from anterior extremity. Intestine narrow, brown-coloured; intestinal caecum long, extending anteriorly approximately along posterior three fifths of length of oesophagus; length of caecum 748, maximum width 60 ( Fig. 26A ). Genital primordium indistinct. Tail conical, 78 long, sharply pointed ( Fig. 26B ).

Host: Coptodon tholloni (Sauvage) ( Perciformes : Cichlidae ).

Site of infection: Encapsulated on intestinal serosa.

Locality: Bas Congo (Congo basin), Democratic Republic of the Congo, no precise location available (collected 29 June 2008).

Prevalence and intensity: 1 nematode found in the only specimen of C. tholloni examined.

Deposition of voucher specimen: IPCAS N-1138.

Remarks. Adults of most species of Dujardinascaris are parasites of crocodilians, only two species, D. malapteruri and D. mormyropsis , are parasitic in African freshwater fishes (see above). The life cycles of species of Dujardinascaris remain unknown, but it can be assumed that freshwater fishes play a role of the intermediate or paratenic hosts, in which nematode third-stage larvae may occur. To date, the only record of Dujardinascaris larvae in fishes is that of Baylis (1928), who collected the larvae presumed to be Dujardinia (= Dujardinascaris ) helicina from the gut of Lates microlepis Boulenger (Latidae) in Lake Tanganyika, Tanzania. However, this is an evident species misidentification, because D. helicina as adult is a parasite of crocodiles in the Neotropical Region ( Sprent 1977, Moravec 2001); moreover, larval morphology does not allow identification to the species level. Therefore, the larvae recorded by Baylis (1928) from L. microlepis should be reported as Dujardinascaris sp. (see Moravec and Jirkû 2014a). Hence, the present finding represents the second record of Dujardinascaris larva from fishes in Africa.

Figures

Fig. 26. A, B – Dujardinascaris sp. third-stage larva from Coptodon tholloni (Sauvage) (anterior and posterior body ends, lateral views).