Two new species of cystidicolid nematodes from the digestive tract of the deep-sea fish <Emphasis Type="Italic">Coryphaenoides mediterraneus</Emphasis> (Giglioli) (Macrouridae) from the Mid-Atlantic Ridge

Two new nematode species, Ascarophis longiovata n. sp. and Neoascarophis longispicula n. sp. (Cystidicolidae), are described from the digestive tract of the marine deep-water fish, the Mediterranean grenadier Coryphaenoides mediterraneus (Giglioli), from the Mid-Atlantic Ridge. The former species is characterised mainly by the structure of the mouth (large pseudolabia, each with well-developed dorsal and ventral extension and small apical protrusion; submedian labia almost absent), the large, elongate-oval, non-filamented eggs (60–66 × 18–27 μm), a cervical inflation of the cuticle, bifurcate deirids, and the length of the spicules (315–360 and 120–147 μm), whereas the latter (only males available) can be distinguished by the length of the spicules (960–1,149 and 258–351 μm) and their length ratio (1:1.91–2.71), the shape of the deirids (bifurcate, with long, narrow posterior arms), and the location of the excretory pore and deirids well posterior to the level of the nerve-ring.