Review of Euchromadorinae (Nematoda: Chromadorida) with description of a new species of Trochamus Boucher & De Bovée, 1971 from the Sundarban, India.

Diagnostic characters for all 11 valid genera of Euchromadorinae are presented with taxonomic key on the basis of morphology of male copulatory apparatus, cuticular pattern, amphideal fovea, and buccal onchia. The key to the species of Trochamus spp. is also constructed with the description of T. timmi sp. n. from the mud-flat of Sundarban, India. The newly described species is different from other Trochamus spp. on the basis of the appearance of lateral differentiation of cuticle, long curved spicule, simple gubernaculum and the presence of pre-cloacal modification in male.

A new free-living marine nematode, Polkepsilonema arabicensis sp. n. (Desmodorida: Epsilonematidae), from Lakshadweep, India.

Polkepsilonema arabicensis sp. n. is discovered from the coralline sand of Lakshadweep island, located off the south-western coast of India. The species differs from other congeners by its unique combination of characters: presence of fine spines along the body curvatures, 5-6 rows of bisinuous ambulatory setae, male with two clusters of ventral copulatory thorns and 14 subcephalic sensilla. The novel species is the fourth discovery of the genus and first record from the coastal areas of Indian subcontinent. A key to species level is provided.

Pseudochromadora benepapillata (Timm 1961) comb. n. (Desmodoridae: Nematoda): revision of its taxonomic status and distribution.

Metachromadora (Bradylaimoides) benepapillata, was first discovered from the coastal mangroves of Bangladesh by Timm (1961). This species was later synonymised with Pseudochromadora cazca, which was described from the Brazilian coast by Gerlach (1956). The present paper proposes to update the taxonomic status of the Timm's species as Pseudochromadora benepapillata comb. n. along with its distribution and comparative morphology. The major differences between P. cazca and P. benepapillata are found in the characteristics of the head capsule; length of cephalic sensilla; length and position of somatic setae; shape of amphideal fovea; shape of spicules and gubernaculum; number and morphology of copulatory and postcloacal thorns. The present report on the occurrence of this species along the eastern most coast of India extends its distribution from the eastern part of Bay of Bengal to its western part.

Cobbia bengalensis sp. nov. (Xyalidae: Monhysterida) from an eroding island of Sundarban, India.

A new species, Cobbia bengalensis sp. nov., of free-living marine nematodes is described from an island of Sundarban, Indian coast and compared with other eight valid species of the genus. Cobbia bengalensis sp. nov. is characterized and differentiated from the others by a unique combination of sexually dimorphic tail, arrangement of anterior sensilla, amphid position, presence of four subcephalic sensilla at the level of amphid, buccal cavity with one dorsal and two subventral teeth, elongated cardia and the shape of gubernaculum. Some previously recorded taxa thought to be the species of Cobbia has also been discussed. Wrongly recorded data for nematofaunal inventory from Indian water has also been criticized.

Cyathoshiva amaleshi gen. n. sp. n. (Nematoda: Cyatholaimidae) from the coast of India.

A new genus, Cyathoshiva, of free-living marine nematodes from the subfamily Cyatholaiminae (family Cyatholaimidae, order Chromadorida), is described from the Indian coast. The new genus differs from other known Cyatholaiminae genera in having a unique combination of morphological characters: buccal cavity with well-developed dorsal tooth and two subventral teeth, proximally unpaired gubernaculum and non-cup shaped supplements. The type species Cyathoshiva amaleshi gen. n. sp. n. is characterized by having multispiral amphids with 4.5 turns, punctated cuticle with a weak lateral differentiation, a conical tail, three supplements possessing both tubular and setoid parts, and a gubernaculum with a serrated and dentate distal end.

Rhynchonema dighaensis sp. nov. (Monhysterida: Xyalidae): a marine nematode from the Indian coast with an illustrated guide and modified key for species of Rhynchonema Cobb, 1920.

A small bodied, free-living marine nematode, Rhynchonema dighaensis sp. nov., is described from the intertidal sand of the east coast of India. It is characterized by having a small buccal cavity, longer left spicule and symmetrical dorsal gubernaculum apophysis. Other species of the genus are discussed with their type locality. A modified key has been prepared for species of Rhynchonema with an illustrated guide. Species of Rhynchonema primarily differ from each other by the shape and size of the spicules, shape of the gubernaculum and dorsal apophysis, size of the buccal cavity and position of the amphid.