Background
The genus Huffmanela Moravec, 1987 (Nematoda, Trichosomoididae, Huffmanelinae), represents a group of nematodes that infect both marine and freshwater fish, and the main gross feature of infection with different species of the genus is the presence of noticeable dark spots or tracks within the parasitized tissues. The
Conclusions
The present study is the first to report the molecular characterization and phylogenetic position of a teleost-associated marine species of the genus Huffmanela. A comprehensive list of nominal and innominate populations of Huffmanela is also provided.
Methods
Nematode eggs with varying degrees of development were separated from the infected tissues (ovary and tunica serosa of stomach) and investigated using light and scanning electron microscopy. Different species-specific markers (small subunit ribosomal DNA, 18S; large subunit ribosomal DNA, 28S; internal transcribed spacer, ITS) were used for molecular identification and phylogenetic study of the new species. Infected tissues were fixed in buffered formalin for pathological investigations.
Results
The fully developed eggs of H. persica sp. nov. are distinguished from those previously described from this host on the basis of their measurements (size, 54-68 × 31-43 µm; polar plugs, 6.4-9.7 × 8.4-12 µm; shell thickness, 3.5-6.1 µm) and a delicate but ornate uterine layer (UL) covering the entire eggshell including the polar plugs. Histopathological examination revealed a fibro-granulomatous inflammation in the ovary and the serosal layer of the stomach of infected fish. Maximum-likelihood (ML) phylogenetic analysis recovered a sister relationship between the new species of marine origin and Huffmanela species previously collected from freshwater hosts. Conclusions: The present study is the first to report the molecular characterization and phylogenetic position of a teleost-associated marine species of the genus Huffmanela. A comprehensive list of nominal and innominate populations of Huffmanela is also provided.