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Issue: Vol. 5862 No. 2: 5 Aug. 2026
Type: Article
Published: 2026-08-05
DOI: 10.11646/zootaxa.5862.2.6
Page range: 315-332
Abstract views: 169
PDF downloaded: 24

Three new species of the genus Microlaimus de Man, 1880 (Nematoda, Microlaimida, Microlaimidae) from the sublittoral of the Northwest Pacific

Far Eastern Federal University; FEFU Campus; 10 Ajax Bay; Russky Island; Vladivostok; 690922; Russia
Far Eastern Federal University; FEFU Campus; 10 Ajax Bay; Russky Island; Vladivostok; 690922; Russia
A.V. Zhirmunsky National Scientific Centre of Marine Biology FEB RAS; 17 Paltcheky St.; Vladivostok; 690041; Russia
Nematoda taxonomy Microlaimus gracilis sp. nov M. kamchaticus sp. nov Microlaimus magnus sp. nov free-living marine nematodes Kamchatka Peninsula Avacha Bay

Abstract

The genus Microlaimus de Man, 1880 has a worldwide distribution. It occurs in diverse coastal environments, ranging from brackish waters and exposed beaches in intertidal and shallow subtidal zones to deep-sea habitats, and inhabits from clay to coarse sediment. Here, we report for the first time the presence of Microlaimus species in the Northwest Pacific. Two new species, Microlaimus gracilis sp. nov. and M. kamchaticus sp. nov., were found in Avacha Bay (Avachinsky Gulf, Kamchatka). Microlaimus gracilis sp. nov. is mainly characterized by a swollen head offset from the body, conspicuous cuticular annulations, small cephalic setae, an amphideal fovea close to the anterior end, and a buccal cavity with three small teeth. M. kamchaticus sp. nov. is distinguished primarily by its short, stout body; finely annulated cuticle; a small amphideal fovea and cephalic setae corresponding to 21–23% of the cephalic diameter; a short cheilostoma with three slight projections; arched spicules (1.2–1.5 times the cloacal body diameter) with a poorly developed capitulum; and a conical tail measuring 3.1–4.0 cloacal body diameters in males. A third species, Microlaimus magnus sp. nov., was found off north-eastern Sakhalin Island, near Piltun Bay (Sea of Okhotsk). It is characterized by a combination of a very large amphideal fovea occupying nearly the entire lateral surface of the cephalic end and the presence of five pre-cloacal supplements.

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How to Cite

Fadeeva, N.P., Keremsheva, E.V. & Karpova, A.A. (2026) Three new species of the genus Microlaimus de Man, 1880 (Nematoda, Microlaimida, Microlaimidae) from the sublittoral of the Northwest Pacific. Zootaxa, 5862 (2), 315–332. https://doi.org/10.11646/zootaxa.5862.2.6