Two new free-living marine nematode species of Xyalidae (Monhysterida) from the Yellow Sea,China

Two new species of free-living marine nematodes Paramonohystera eurycephalus sp. nov. and Steineria sinica sp. nov. from the Yellow Sea, China are described. Paramonohystera eurycephalus sp. nov. is characterized by relatively wide head diameter (33 μm in width), large cup-shaped buccal cavity; presence of numerous long cervical setae; amphidial fovea 18–20 μm in diameter; spicules slender, arcuate, 3.1–3.2 anal body diameter; gubernaculum tubular with a distal hook; five to six minute precloacal supplements. Steineria sinica sp. nov. is characterized by eight groups of three subcephalic setae at almost same level as cephalic setae; eight groups of two long cervical setae situated between subcephalic setae and amphidial fovea; amphidial fovea round, 35% of corresponding body diameter, about one head diameter from anterior end; spicules slender, cephalate proximally and taper distally; gubernaculum pipe-shaped with dorsocaudal apophysis; tail conico-cylindrical with three long terminal setae.