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Populations of Stegelleta are described from California, New Zealand and Senegal. An amphimictic population from California is identified as belonging to S. incisa and compared with type specimens from Utah and an amphimictic population from Italy. One population from New Zealand is close to S. incisa but considered to represent a new species, Stegelleta laterocornuta sp. nov. It is particularly characterised by a 379–512 μm long body in females and 365–476 μm in males; cuticle divided into 16 rows of blocks at midbody (excluding lateral field); lateral field with four incisures; three pairs of asymmetrical lips, U-shaped primary axils without guarding processes, each lip asymmetrically rectangular with a smooth margin, only lateral lips have slender acute tines; three labial probolae, bifurcated at half of their length; vulva without flap; spermatheca 17–31 μm long; postuterine sac 7–24 μm long; spicules 21.5–23.5 μm long. Other specimens from New Zealand are identified as belonging to S. tuarua. A parthenogenetic population from Senegal is identified as belonging to S. ophioglossa and compared with type specimens from Mongolia and records of several other populations of S. ophioglossa. The generic diagnosis is emended and a key to the species of Stegelleta is provided.
Eight species of Diplopeltoides are described from the Swedish west coast. Diplopeltoides suecicus sp. nov. has the cuticle with longitudinal striation visible only under SEM; cuticular plate underlying the cephalic cuticle around the amphid present; cephalic sensilla 4–6 μm long; amphid an inverted U-shape; wide space between amphidial branches areolated; spicules 27–31 μm long; gubernaculum with caudal apophysis. Diplopeltoides longicaudatus sp. nov. is characterized by a cuticle without longitudinal striation; cuticular plate underlying cephalic cuticle around amphid present; cephalic sensilla 13 μm long; amphid an inverted U-shape; narrow space between amphidial branches not ornamented; spicules unequal in size, 27–31 μm long; gubernaculum absent; midventral precloacal cuticular ridge present. D. grandis sp. nov. is characterized by a cuticle with longitudinal striation; cuticular plate underlying cephalic cuticle around amphid present; cephalic sensilla 18.5 μm long; amphid an inverted U-shape; wide space between amphidial branches punctate. The following taxonomic changes are proposed: Diplopeltoides asetosus (Juario, 1974) comb. nov., Diplopeltoides botulus (Wieser, 1959) comb. nov., Diplopeltoides bulbosus (Vitiello, 1972) comb. nov., Diplopeltoides lucanicus (Boucher & Helléouët, 1977) comb. nov., Diplopeltoides pumilus (Vincx & Gourbault, 1992) comb. nov. and Diplopeltoides striatus (Gerlach, 1956) comb. nov. Diplopeltoides holovachovi Fadeeva & Mordukhovich, 2013 is synonymised with Diplopeltoides pumilus comb. nov. An updated key to the species of Diplopeltoides is provided.
Two species of the nematode family Diplopeltidae are described from Skagerrak. The new genus Belgopeltula gen. nov. is proposed for Diplopeltula belgica Vincx & Gourbault, 1992 and is characterised by: amphidial fovea circular in female and double-loop-shaped in male; excretory pore located at the level of cephalic setae bases; oral opening on the dorsal side of the body; pharynx subdivided into strongly muscularised fusiform corpus and weakly muscularised narrow and long postcorpus; female didelphic with antidromously reflexed ovaries; supplements absent. Mudwigglus micramphidium sp. nov. is characterised by: a body of 0.6 mm long; cephalic sensilla 1.5 μm long; amphidial fovea loop-shaped, 8 μm long and 3.5 μm wide; gymnostom without cuticularised ring; tail elongate conoid, with subcylindrical distal part; terminal setae absent; spicules 15 μm long; gubernaculum present; two midventral precloacal setae. It is distinguished from M. macramphidium Leduc, 2013 in having shorter amphidial fovea, shorter spicules and presence of two precloacal setae. Redescription of Diplopeltis cylindricauda Allgén, 1932 is provided based on type material. Diplopeltula minuta Vitiello, 1972 is transferred to the genus Mudwigglus Leduc, 2013. Diplopeltis cylindricauda Allgén, 1932, Diplopeltula laminata Vitiello, 1972 and Diplopeltula cassidaignensis Vitiello, 1972 are transferred to the genus Pseudaraeolaimus Chitwood, 1951.
The new genus Neodiplopeltula gen. nov. is proposed to accommodate those species from the genus Diplopeltula Gerlach, 1950 that possess the following morphological characters: amphids in the shape of an elongated loop, a well-developed subcylindrical stoma and outstretched ovaries. The genus Diplopeltula is considered genus inquirendum et incertae sedis. Four species placed in Neodiplopeltula gen. nov. are redescribed. The following taxonomic changes are proposed: Neodiplopeltula asymmetrica (Allgén, 1935) gen. et comb. nov.; Neodiplopeltula barentsi (Steiner, 1916) gen. et comb. nov.; Neodiplopeltula bathmanni (Jensen, 1991) gen. et comb. nov.; Neodiplopeltula cuspidiboja (Leduc, 2017) gen. et comb. nov.; Neodiplopeltula indica (Gerlach, 1962) gen. et comb. nov.; Neodiplopeltula intermedia (Gerlach, 1954) gen. et comb. nov.; Neodiplopeltula obesa (Nguyen Vu Thahn, Nguyen Thahn Hien & Gagarin, 2012) gen. et comb. nov.; Neodiplopeltula onusta (Wieser, 1956) gen. et comb. nov.; Neodiplopeltula ovalis (Ditlevsen, 1928) gen. et comb. nov. and Neodiplopeltula tchesunovi (Fadeeva & Mordukhovich, 2013) gen. et comb. nov. New synonyms include: Diplopeltis asymmetricus Allgén, 1935 and Diplopeltis ovalis Ditlevsen, 1928 are synonimised with Neodiplopeltula barentsi (Steiner, 1916) gen. et comb. nov.; Diplopeltula tchesunovi Fadeeva & Mordukhovich, 2013 is synonimised with Neodiplopeltula onusta (Wieser, 1956) gen. et comb. nov.; the male of Diplopeltula cuspidiboja Leduc, 2017 is synonimised with Neodiplopeltula barentsi gen. et comb. nov. and the female with N. bathmanni gen. et comb. nov. A key to the species of Neodiplopeltula gen. nov. is provided.
The new genus and species Campydoroides manautei Holovachov gen. et sp. nov. is placed in the suborder Campydorina and is characterised by a transversely striated cuticle without lateral alae, body pores or epidermal glands; somatic sensilla only on pharyngeal region and on tail; a truncate labial region with papilliform inner labial, outer labial and cephalic sensilla; a stirrup-shaped amphid with transverse slit-like opening; a conoid stoma with strongly cuticularised walls and large protrusible dorsal tooth; a cylindrical pharynx with distinct basal bulb but without valves; a large ovoid cardia; didelphic, amphidelphic female gonads with antidromously reflexed ovaries and without spermatheca; a transverse vulva; a straight vagina without pars refringens vaginae or epiptygmata; an elongate tail with caudal glands and spinneret. The new genus is similar to the genera Campydora Cobb, 1920 and Udonchus Cobb, 1913 in having papilliform labial and cephalic sensilla, a stirrup-shaped amphid with a transverse slit-like opening, a stoma with a well-developed protrusible dorsal tooth, and a muscular pharynx with a strongly developed basal bulb, but can be easily separated from both in details of a stoma morphology. The systematics of the suborder Campydorina is revised. Halirhabdolaimus Siddiqi, 2012 is synonymised with Syringolaimus de Man, 1888.
This paper reports on the genus Cobbionema Filipjev, 1922 in Sweden with the description of four species and a revision of the genus. Cobbionema acrocerca Filipjev, 1922 is relatively small in size, with a tail that has a conical proximal and a digitate distal section. Cobbionema cylindrolaimoides Schuurmans Stekhoven, 1950 is similar to C. acrocerca in most characters except having a larger body size and heavily cuticularized mandibles. Cobbionema brevispicula sp. nov. is characterised by short spicules and a conoid tail. Cobbionema acuminata sp. nov. is characterised by a long two-part spicule, a conical tail and three (one mid dorsal and two ventrosublateral) sharply pointed tines in the anterior chamber of the stoma that are located more anterior than in all the other species. We also present a molecular phylogeny of the family based on the nearly full-length 18S and the D2-D3 expansion segment of the 28S rRNA genes. Maximum Likelihood and Bayesian trees inferred from both genes strongly support a clade that included Cobbionema, Demonema Cobb, 1894 and Halichoanolaimus de Man, 1888 and another clade with Gammanema Cobb, 1920 and Latronema Wieser, 1954 nested together. None of the trees supported the monophyly of the subfamilies Choniolaiminae and Selachinematinae.
A new species of Paracrobeles, P. kelsodunensis sp. nov. is described from the Kelso Dunes area, Mojave National Preserve, southern California. Paracrobeles kelsodunensis sp. nov. is particularly characterised by a body length of 469–626 μm in females and 463–569 μm in males; lateral field with four incisures, extending almost to tail terminus; three pairs of asymmetrical lips, separated by U-shaped primary axils with two long guarding processes, each lip usually with four tines along its margin; three long labial probolae, deeply bifurcated, with slender prongs without tines; metastegostom with a strong anteriorly directed dorsal tooth; pharyngeal corpus anteriorly spindle-shaped, posteriorly elongate bulbous with dilated lumen; spermatheca 24–87 μm long; postvulval uterine sac 60–133 μm long; vulva in a sunken area; spicules 33–38 μm long; and male tail with a 5–8 μm long mucro. The generic diagnosis is emended on the basis of recently described species and a key to the species of Paracrobeles is provided.
