ABSTRACT
The family Enchelidiidae is recovered as monophyletic and appears to be a more recently derived taxon within the superfamily Oncholaimoidea. It combines nematodes with buccal cavity with three unequal teeth, crenate pharynx, and absence of demanian system. Genus Thoonchus was erected for nematodes characterized by the large buccal cavity with heavily cuticularized walls and several rows of denticles, short and arcuate spicules and gubernaculums with expanded corpus. One new species is described here from the Sishili Bay, located in the northern Yellow Sea. Thoonchus covidus sp. nov. is characterized by the body length 3195â4339 µm, outer labial and cephalic setae in one circle, pocket shaped amphid above the buccal cavity base, secretory-excretory pore at the base of cephalic setae, arched spicules, gubernaculum with thin proximal extension parallel to spicules, preanal supplement absent, three pairs of preanal papillae. It differs from other congeners by the position of secretory-excretory pore, absence of supplementary organ in males and presence of three pairs of precloacal papillae. Redescription of T. giganticus is also provided. After critical evaluation of the genus we recognize 4 valid species and provide a taxonomic key to species.
Subject(s)
Enoplida , Nematoda , Animals , MaleABSTRACT
The family Sphaerolaimidae Filipjev, 1918 combines nematodes characterized by finely striated cuticle, round amphids, broad buccal cavity with longitudinal ribs, and females with one anterior ovary. Sphaerolaimus Bastian, 1865 species from this family are found in intertidal and subtidal sediments and have also been reported from mangroves and estuary. Three new species of Sphaerolaimus were found and described from the South China Sea. Sphaerolaimus callisto sp. nov. is characterized by the relatively long body, small amphids and long spicules. Sphaerolaimus callisto sp. nov. is similar to S. cuneatus Paramonov, 1929, but differs by the longer body (2350-2690 µm vs 1980-1990 µm), index b (5.1-5.6 vs 3.9-4.1), absence of precolacal supplements, and longer spicules (321-356 µm vs 270 µm). Sphaerolaimus ganymede sp. nov. is characterized by large amphids and the presence of sexual dimorphism in amphid size. Sphaerolaimus ganymede sp. nov. is close to Sphaerolaimus maeoticus Filipjev, 1922, but differs by the presence of lateral alae, indexes a (12.3-17.5 vs 20-27) and c (7.9 vs 9-10), bigger amphids in male (14.6-15.7 µm vs 11 µm). Sphaerolaimus io sp. nov. is characterized by small amphids and short apophyses of gubernaculum. Sphaerolaimus io sp. nov. is similar to Sphaerolaimus pacificus Allgen, 1947, but differs by bigger size (1480-1525 µm vs 1140 µm), presence of lateral alae, and index c (7.5-8 µm vs 14.3 µm). After critical evaluation of the genus we recognize 35 valid species and provide dichotomous and pictorial keys to species.
Subject(s)
Nematoda , Animals , China , Chromadorea , Female , Male , MouthABSTRACT
The family Sphaerolaimidae Filipjev, 1918 includes nematodes that are characterized by the finely striated cuticle, round amphids, broad buccal cavity with longitudinal ribs, and single anterior ovary in females. Parasphaerolaimus species from this family are found in intertidal and subtidal sediments and have also been reported from mangroves and estuaries. Parasphaerolaimus pilosus sp. n. is characterized by the moderately plump body, presence of lateral alae, long cervical setae, small amphids in males, and relatively short spicules. As a result of a comprehensive evaluation of species descriptions, eight species in the genus Parasphaerolaimus are recognized valid, and an identification key to species level is provided.
Subject(s)
Nematoda , Adenophorea , Animals , Female , MaleABSTRACT
A new representative of the family Phanodermatidae, Phanodermopsis nana sp. n., is described. The new species is found in the Sea of Japan and characterized by its small body size, long anterior sensilla and short tail. The new species differs from P. ingrami in body length (~ 7000 µm in P. ingrami vs ~ 3000 µm in P. nana sp. n.). The De Man's ratios (a, b, c) are smaller in P. nana sp. n. and the outer labial setae are longer (1 corresponding body diameter) than in P. ingrami (1/2 corresponding body diameter). The vulva is more posterior in P. ingrami (V% = 58-61%) than in P. nana sp. n. (V% = 51-58%). A dichotomous key to the 9 valid genera of Phanodermatidae and a pictorial key to species of Phanodermopsis are provided. The length of the spicules is proposed as the main differentiating feature for distinguishing Phanodermopsis and Crenopharynx species. Phanodermopsis longisetae Chitwood, 1936 which has extremely long spicules (5.2 anal body diameters) is transferred to the genus Crenopharynx.
