Raphidascaris (Raphidascaris) macrouri n. sp. (Nematoda: Anisakidae) from two deep-sea macrourid fishes in the Western Mediterranean: Morphological and molecular characterisations

- First nematode of the genus Raphidascaris described from macrourid fishes
- High variability on tail tip morphology of Raphidascaris macrouri
- High number and variability of papillae and short subequal spicules of males
- Raphidascaris macrouri has been characterised at the nuclear ribosomal gene ITS.

A new nematode species, Raphidascaris (Raphidascaris) macrouri n. sp. (Anisakidae), is described from male and female specimens found in the intestine, and occasionally in stomach and pyloric caeca, of two deep-water macrourid fishes (Gadiformes) off Barcelona, Mediterranean Sea: Nezumia aequalis (Günther) (type-host) and Trachyrincus scabrus (Rafinesque). Based on light and scanning electron microscopy examination, the new species shows similar morphological features as the other four valid species of the subgenus Raphidascaris Railliet & Henry, 1915, but it differs from Raphidascaris (Raphidascaris) acus (Bloch, 1779), Raphidascaris (Raphidascaris) lutjani Olsen, 1952 and Raphidascaris (Raphidascaris) mediterraneus Lèbre & Petter, 1983 in the high number of precloacal papillae (23-32) and from Raphidascaris (Raphidascaris) gigi Fujita, 1928 in the length of the spicules. Moreover, Raphidascaris (Raphidascaris) macrouri n. sp. exhibits a high variability on the number and distribution of caudal papillae, which was not recorded in the other four mentioned species. This is the first species of this subgenus reported from the family Macrouridae. Sequences of ITS1-5.8S-ITS2 region are analysed and compared with closely related nematode species. Molecular analysis confirmed the uniformity of the R. (R.) macrouri n. sp. between hosts.

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