Chromaspirina aliapapillata sp.nov. (Nematoda, Desmodorida) from Donuzlav Bay (Crimea, Black Sea).

A new species of free-living marine nematode Chromaspirina aliapapillata sp. nov. from the Donuzlav Bay (Black Sea) is described. Chromaspirina aliapapillata sp. nov. is characterized by a slender body, buccal cavity with two dorsal teeth, spiral amphids, tail conico-cylindrical and presence of precloacal supplements. The new species differs from other known species of the genus by having two dorsal teeth and presence of 17 to 21 precloacal supplements of which one or two are cup-shaped and rest curved tubes.

Two species of the genus Theristus Bastian, 1865 (Nematoda: Xyalidae) from the hypersaline water bodies of the Crimea (Azov-Black Sea basin).

Morphological descriptions of two species of the genus Theristus Bastian, 1865 belonging to group flevensis, found in the hypersaline water bodies of the Crimean Peninsula, are presented. Theristus siwaschensis sp. n. is morphologically closest to T. flevensis Schuurmans Stekhoven, 1935, T. parambronensis Timm, 1952, T. macroflevensis Gerlach, 1954, T. metaflevensis Gerlach, 1955, but differs from them by the structure of the reproductive system in females, number of cephalic setae and size of spicules. Specimens of T. flevensis found in the Lake Chersonesskoye are similar to the re-description of a large forms of T. flevensis from Chile by Murhy (1966) and Caspian Sea by Chesunov (1981). However, it differs from the Caspian Sea species by having larger amphids, longer cephalic setae and spicules. T. pratti Murph Canaris, 1964 and T. ambronensis Schulz, 1937 are synonymized with T. flevensis.

A new species of Microlaimus de Man 1880 (Nematoda: Microlaimidae) from the Black Sea.

Microlaimus sergeevae sp. n. is described and illustrated from the Crimea shelf of the Black Sea. It is characterized by the 1301-1728 µm long body; cuticle with distinct annuli; spicules 34-37 µm long, curved; gubernacular apophyses 20-25 µm long, surrounding distal end of spicules; criptocyrcular amphidial fovea 7-8 µm in diameter; cervical setae present; four submedian rows of pores spreading along the whole body length, and eight precloacal supplements in males. The new species morphologically resembles M. gerlachi Wieser 1954, M. paraborealis Allgen 1940a and M. kaurii Wieser 1954, but differs from them by the length of cephalic setae, size of the body, presence of cervical setae, shape of the gubernacular apophyses, eight tubular precloacal supplements and submedian rows of pores spreading along the whole body length. M. sergeevae sp. n. differs from M. gerlachi by having a smaller amphidial fovea, shorter spicules and gubernacular apophyses. The new species differs from M. paraborealis by having larger value of c. It differs from M. kaurii by having longer spicules and larger values of c and b.

Two new species of free-living nematodes genera Microlaimus de Man, 1880 and Aponema Jensen, 1978 (Nematoda: Microlaimidae) from the Black Sea.

Two new species of the family Microlaimidae Micoletzky, 1922 are described and illustrated from the Black Sea. Aponema pontica sp. n. is morphologically closest to A. torosum in the shape of the body and spicules, size of amphids, but differs in having small and triangular cardia, absence of constriction in head region, shape of gubernaculum apophyses, rounded and weakly sclerotised lumen of pharyngeal bulb and longer spicules. Microlaimus paraglobiceps sp. n. morphologically resembles M. globiceps de Man, 1880 in the shape of the body, structure of the male sexual organs and presence of precloacal pore, but the main difference is a shorter body, cuticle finely annulated all over the body and absence of sexual dimorphism in the size of amphideal fovea.