Species of Benthimermis Petter, 1980 from different parts of the world ocean from depths between 630 and 5880 m were examined. This resulted in new findings of B. filiformis Petter, 1987, B. hureaui Petter, 1983, and B. marionensis Petter, 1983 and description of seven new species. The female of B. ifremeri n. sp. differs from B. arnaudi Petter, 1983 in the absence of a caudal terminal knob, a thinner body, and a longer tail; from B. edouardensis Petter, 1983 in a smaller body length and a longer tail; from B. minuta Petter, 1987 in a longer and thicker body and a shorter tail. The male of B. improvisa n. sp. has thin and pointed cephalic setae and a round ventral gland at the level of amphid, which opens outside. The female of B. petterae n. sp. differs from B. laubieri Petter, 1987 by pocket-shaped amphidial foveae and reflected ovaries. The male of B. petterae n. sp. has a small caecum in the anterior part of the posterior testis. The male of B. platyptera n. sp. has the fewest number of supplementary organs (two), shortest spicules, and the smallest body length. The female of B. pseudominuta n. sp. differs from B. laubieri by its rounded posterior end, smaller body length, and a thicker body. The female of B. tchesunovi n. sp. differs from B. australis Petter, 1983 and B. hureaui in its smaller body length, the presence of a cuticular thickening at the cephalic apex, and smaller eggs. The female of B. turpicauda n. sp. has a caudal terminal spine of irregular shape, transversal circular ridges of the hypodermis at the level of the junctions of trophosomal cells, and hologonic ovaries.
Nematoda, Benthimermithidae, Benthimermis, parasite, deep-sea, new species.