Three new species of Microlaimus (Nematoda: Microlaimidae) from the South Atlantic.

Three new species of Microlaimus are described from the continental shelf of the Campos Basin, southwest Atlantic, Brazil. Microlaimus campiensis sp. n. differs from all other species in the presence of two anterior testes, slender spicules with enlarged proximal ends, 7-11 pre-cloacal papilliform supplements, and females with a pair of constriction structures, one on each branch of the ovary. Microlaimus alexandri sp. n. shows sexual dimorphism in the size of the amphidial fovea, which occupies 100% of the diameter of the corresponding area in the male; the buccal cavity provided with five teeth and a slightly cuticularized cuticular ring. Microlaimus vitorius sp. n. has four longitudinal-lateral rows of glands associated with small pores, one seta and three pores small pre-cloacal, and the gubernaculum has a triangular base. An amendment to the diagnosis of the genus is proposed, where the number of teeth was modified.

A new genus with three new species of free-living marine nematodes of the subfamily Desmodorinae (Nematoda: Desmodoridae), from the continental shelf off northeastern Brazil.

Three new species representing a new genus of marine nematodes were collected on the continental shelf of the Potiguar Basin, northeastern Brazil. Spinonema gen. n. has a coarsely annulated cuticle with the inner layer ornamented with vacuoles, and lateral alae. The lateral alae are formed by raised and bent lateral sections of annules, resembling the letter C. C-shaped refers to each individual segment of ala. Some species have a dorsal spine, arched spicules and a well-developed head capsule, with a thick cuticle without annulations. Spinonema gen. n. has some features in common with certain genera of the family Desmodoridae but can be distinguished by the coarse body annuli, cuticular ornamentation (lateral alae, and in some species a dorsal spine) and the absence of subcephalic setae. The type species of the new genus, Spinonema cuticulatum gen. et sp. n., is characterized by the presence of a spiral fovea amphidialis, hook-shaped spicules in the capitulum, a velum and three ejaculatory glands. Spinonema spirale gen. et sp. n. has body annuli with the inner cuticle ornamented with vacuoles along the entire body, a multispiral fovea amphidialis with 3.15 turns and a gubernaculum intricate, with lateral crurae. Dorsal apophysis of gubernaculum wing-shaped. Spinonema absente gen. et sp. n. has a cryptospiral fovea amphidialis, short spicules, a simple gubernaculum and three precloacal setae.

The genus Bolbonema Cobb, 1920 (Nematoda: Desmodoridae): emended diagnosis, key to males, and description of three new species from the continental shelf off northeastern Brazil.

The marine nematode genus Bolbonema has three valid species, the most recent one described eight years ago. Characteristics of the genus include the well-defined globular cephalic capsule and the long and short somatic setae along the body. Three previously undescribed species of this genus were collected on the continental shelf of the Potiguar Basin in northeastern Brazil. Bolbonema braziliensis sp. n. has a relatively large cryptospiral fovea amphidialis, gubernaculum a bent rod dorsally oriented and two subventral precloacal setae inserted on two small papillae above the cloaca. Bolbonema papillae sp. n. has a large multispiral fovea amphidialis with three turns, arched spicules with the proximal region rounded, a laminar and well-developed gubernaculum enfolding the distal portion of the spicules, and two subventral precloacal papillae just above the cloaca. Bolbonema zildae sp. n. has a spiral fovea amphidialis, no supplements, arched spicules with a velum, and the gubernaculum with a dorsal apophysis. These three new species increase to six the number of taxa known in the genus. A dichotomous key based on males, an emended diagnosis of the genus, and the first record of Bolbonema brevicolle Cobb, 1920 from Brazil are provided.