Three new nematode species were found in the Angola Basin (south-east
Atlantic Ocean) at depths of about 5500 m. Paracyatholaimus diva sp.
nov. (Cyatholaimidae) is characterised by outer labial and cephalic
setae of about 3-5 mu m, multispiral amphidial fovea with six turns in
males and four turns in females situated at the level of the dorsal
tooth, buccal cavity armoured with only one prominent dorsal tooth,
tail consisting of anterior conical and posterior slender cylindrical
half portions, and six preanal midventral setose supplementary organs.
Paracyatholaimus diva sp. nov. is most similar to Paracyatholaimus
rotundus Gerlach, 1964 but differs by slightly longer body (936-1176 mu
m versus 705 mu m), tail shape (with clearly narrowed posterior half
versus conical), six versus four supplementary organs of different
shape. The genus Paracyatholaimus Micoletzky, 1923 is briefly reviewed.
The genus now includes twenty-four valid species. Five species are
considered as species inquirendae, mainly because of inadequate type
material lacking adult stages and/or incomplete descriptions. A
pictorial guide for identification of the valid species of
Paracyatholaimus is provided. Pomponema proximamphidum sp. nov. shares
subapical position of the amphidial fovea and distinct lateral
differentiation of the somatic cuticle with five Pomponema species: P.
concinnum Wieser, 1954, P. corniculata Gourbault, 1980, P. mirabile
Cobb, 1917, P. multipapillatum Filipjev, 1922 and P. stomachor Wieser,
1954 but differs from them by tail length, longer posterior cylindrical
portion of the tail, relative width of the amphidial fovea, position of
the ventral pore and lesser number of supplementary organs. Desmodora
striatocephala sp. nov. is well characterized by a combination of very
large amphidial fovea occupying nearly the entire lateral surface of
the cephalic capsule and thickened midventral preanal cuticle with a
few supplementary papillae inserted therein in males. D. striatocephala
sp. nov. differs from related species D. cuddlesae Inglis, 1963 and to
some lesser degree with D. inflexa Wieser, 1954 with shorter body,
relative tail length, bigger size of the amphidial fovea and lesser
number of supplementary papillae.