3.3.5. Differential Diagnosis

*L. obscuramphis* sp. n. differs considerably from most *Latronema* species by combination of body size, anterior setae length, size and shape of amphideal fovea, size of spicules, number of preanal supplementary organs. *L. aberrans* (Allgén, 1934), *L. annulatum* (Gerlach, 1953), and *L. spinosum* (Andrássy, 1973) are closest to *L. obscuramphis* in characters cited above. *L. obscuramphis* differs from *L. aberrans* (the species known from the west Baltic Sea and White Sea) by smaller body length (male, L 591 versus 960 μm; females, L 666–718 versus 1140 μm) and lesser number of preanal supplementary organs (8 versus 13); from *L. annulatum* (Madagascar, littoral) by tail shape (in male c' 1.64 versus 2.4–2.8), longer spicules (38 μm versus 27 μm), and lesser number of supplements (8 versus 12); and from *L. spinosum* (Cuba, only female known) by no spinose body cuticular rings, smaller body (666–718 versus 850–1062 μm), and lesser index b (3.8–4.4 versus 4.5–5).
