Two new nematode species of the genus Zalonema (Desmodorida, Desmodoridae, Desmodorinae) from mangrove wetlands, China

Two new species of the genus Zalonema Cobb, 1920 were identified during a meiofaunal survey of mangrove sediment in China. Zalonema eurysbucca sp. nov. is characterized by body length 1772–2309 µm, cuticle with transverse annuli; cephalic setae measuring 1–2 µm, and eight subcephalic setae (2–3 µm) arranged in a circle between the cephalic setae and the anterior margin of the amphid; amphideal fovea (4–4.5 turns) located laterally on the main posterior portion of the cephalic capsule; buccal cavity large and cup-shaped, with twelve cheilorhabdia in the vestibule, a cuticularized dorsal tooth, and minute ventral tooth; males possess lateral and ventral alae; spicule length (as arc) about 1.13–1.34 times the anal body diameter (abd); a small cup-shaped preanal supplement is present, and the ventral ala exhibit pore-like depressions at the somatic setae positions.

Zalonema cylindribucca sp. nov. is distinguished by the following characteristics: body length 1158–1451 μm; cuticle with transverse annuli; four cephalic setae (2–3 µm) and eight subcephalic setae (2–3 µm) arranged in separate circular rows; amphideal fovea with 3–3.5 turns; cylindrical buccal cavity containing 12 cheilorhabdia arranged circularly in the vestibule; a large dorsal tooth located near the cheilorhabdia base and a small ventral tooth at the buccal cavity’s base; males possess both lateral alae and ventral ala, spicules measuring 1.07–1.19 times the anal body diameter (as arc), a small cup-shaped preanal supplement present, and the ventral ala exhibit small pore-like depressions at somatic setae positions.