Three species of monhysterids (Nematoda, Monhysterida) from mangrove forest of the Me Kong river estuary, Vietnam

Three new free-living nematode species of the order Monhysterida from Me Kong river estuaries of Vietnam are described. Daptonema brevisetosum sp. nov. resembles to Daptonema setosum (Bütschli, 1874), but differs from it by the relatively shorter outer labial setae, shorter spicules and shorter cervical and somatic setae. Subsphaerolaimus major sp. nov. similar to Subsphaerolaimus lamasus (Gerlach, 1956), Subsphaerolaimus gerlachi (Wieser, 1959) and Subsphaerolaimus litoralis Lorenzen, 1978, but differs from them by the longer body, longer spicules and presence of dorso-caudal apophysis of gubernaculum. Daptonema hirtum (Gerlach, 1957) is restored from synonymy of Daptonema setosum (Bütschli, 1874) and it is raised to range of valid species

Four new species of monhysterids (Nematoda: Monhysterida) from mangroves of the Mekong river estuaries of Vietnam

Four new free-living nematode species of the order Monhysterida from Me Kong River estuaries of Vietnam are described. Thalassomonhystera tenuis sp. nov. resembles to Thalassomonhystera pusilla (Boucher, Heleouët, 1977) but differs from it by the high, isolated labial region, longer outer labial setae, shorter oesophagus, shorter spicules, absence of gubernaculum’s dorso-caudal apophysis and presence of subterminal setae on the tip. Diplolaimelloides elegans sp. nov. resembles to Diplolaimelloides meyli Timm, 1961, but it differs in having longer and slender tail and vulva position located in more anterior body end. Sphaerotheristus supplementatus sp. nov. comes close to Sphaerotheristus parvus Gagarin, Nguyen Vu Thanh, 2006, it differs in having the longer and thinner body and papillae-shaped supplements in males. Terschellingia obesa sp. nov. similar to Terschellingia monohystera Wieser, Hopper 1967 and Terschellingia brevicaudata Ott, 1972, but it differs from T. monhystera in having shorter cephalic setae, others vulva position and absence of oesophagus basal bulb; it also differs from T. brevicaudata in having shorter body, shorter cephalic setae, shorter spicules and presence of one ovary

Two new species of the genus Halaphanolaimus De Man, 1876 (Nematoda: Leptolaimidae) from Can Gio mangrove forest, Vietnam

New brackish water nematode species Halaphanolaimus cangionensis sp.nov, and Halaphanolaimus rivalis sp.nov collected from Cangio mangrove forest, Hochiminh city of Vietnam are described. Halaphanolaimus cangionensis sp.nov is characterized by the absence of somatic and cervical setae, comparatively slender tail, presence of caudal apophysis of the gubernaculum and comparatively short spicules. New species Halaphanolaimus cangionensis sp.nov resembles to Halaphanolaimus harpaga Boucher, Bovee, 1972 and Halaphanolaimus luridus (Timm, 1963) but differs from H. harpaga by the absence of somatic and cervical setae, more anterior position of vulva, another structure of gubernaculums and other arrangement of precloacal supplements. The new species differs from H. luridus by the more slender tail, longer stoma, another structure of gubernaculums and shorter spicules. Halaphanolaimus rivalis sp.nov is characterized by the presence of somatic and servical setae, long spicules and pre-equatorial vulva. New species Halaphanolaimus rivalis sp.nov, resembles to Halaphanolaimus luridus (Timm, 1963) and L. lorenzeni Boucher, Bovee, 1972 but H. rivalis sp.n. differs from H. luridus by the presence of somatic and cervical setae, more wide labial region, longer stoma, shorter spicules. H. rivalis sp.n. differs from H. lorenzeni by the thicker body, longer stoma and longer spicules. Key to six valid species of the genus Halaphanolaimus are given.

Two new nematode species of the family Diplopeltidae Filipjev, 1918 (Nematoda, Araeolaimida) from coast of Vietnam

Two new species of free-living marine nematodes from West Sea (Gulf of Siam), coast of Vietnam, were described and illustrated. Diplopeltula obesa sp. n. differs from D. indica Gerlach, 1962 by possessing shorter and thicker body, comparatively longer tail and shorter cephalic setae, Campylaimus gracilis sp. n. resemble to C. minor Timm, 1961, but differs from the later by having an another shape of amphidial fovea, another position of mouth, longer body and shorter cephalic setae.Two new species of free-living marine nematodes from West Sea (Gulf of Siam), coast of Vietnam, were described and illustrated. Diplopeltula obesa sp. n. differs from D. indica Gerlach, 1962 by possessing shorter and thicker body, comparatively longer tail and shorter cephalic setae, Campylaimus gracilis sp. n. resemble to C. minor Timm, 1961, but differs from the later by having an another shape of amphidial fovea, another position of mouth, longer body and shorter cephalic setae

FIGURE 5 in Four new species of free-living marine nematodes of the family Comesomatidae (Nematoda: Araeolaimida) from coast of Vietnam

FIGURE 5. Dorylaimopsis brevispiculata sp. n. A: Entire male; B: Entire female; C: Male head; D: Cardial region of male; E: Spicular apparatus; F: Male tail; G: Female tail. Scale bars: A, B—150 µm; D—70 µm; G—50 µm; F—40 µm; C—15 µm.Published as part of Gagarin, Vladimir G., 2013, Four new species of free-living marine nematodes of the family Comesomatidae (Nematoda: Araeolaimida) from coast of Vietnam, pp. 547-560 in Zootaxa 3608 (7) on page 558, DOI: 10.11646/zootaxa.3608.7.2, http://zenodo.org/record/21975

Microlaimus capitatus sp. n. and Dichromadora simplex Timm, 1961 (Nematoda, Chromadorea) from the coast of Vietnam

Gagarin, Vladimir G. (2020): Microlaimus capitatus sp. n. and Dichromadora simplex Timm, 1961 (Nematoda, Chromadorea) from the coast of Vietnam. Zootaxa 4732 (2): 323-331, DOI: https://doi.org/10.11646/zootaxa.4732.2.

Four new species of free-living marine nematodes of the family Comesomatidae (Nematoda: Araeolaimida) from coast of Vietnam

Gagarin, Vladimir G. (2013): Four new species of free-living marine nematodes of the family Comesomatidae (Nematoda: Araeolaimida) from coast of Vietnam. Zootaxa 3608 (7): 547-560, DOI: http://dx.doi.org/10.11646/zootaxa.3608.7.

FIGURE 2 in Lanzavecchia mangrovi sp. n. (Nematoda, Dorylaimida) from mangroves of Red River Estuary, Vietnam.

FIGURE 2. Lanzavecchia mangrove sp. n., paratypes male and female. A: male, entire body; B: male, head; C: male, anterior body end; D: female, vulva region; E: female, posterior body end; F: male, posterior body end. Scale bars: A=250µm; E=100µm; C,D,F=50µm; B=20µm

Two new nematode species of the genus <i>Tobrilus</i> Andrássy, 1959 (Nematoda, Triplonchida) from Lake Baikal, Russia

Two new nematode species of the genus Tobrilus Andrássy, 1959 from Lake Baikal are described and illustrated. The first species Tobrilus elginus sp. nov. was found in the littoral zone of Maloye More Bays. The second species Tobrilus juliae sp. nov. dwells on bodies of dead sponges Lubomirskia baicalensis (Pallas, 1776). Tobrilus elginus sp. nov. is most similar to T. amabilis Tsalolikhin, 1974 and T. bekmanae Tsalolikhin, 1975. In contrast to the first species it has a shorter body and spicules, longer gubernaculum and a shorter supplements row. Its body is shorter and thinner, tail and supplement row are shorter and the vulva is more posterior as compared to the second species. The body size of Tobrilus juliae sp. nov. is most similar to T. securus Gagarin &amp; Naumova, 2011 and T. saprophagus Naumova &amp; Gagarin, 2017. From the first of these species it differs by the thinner body, shorter tail, comparatively shorter outer labial setae and shorter spicules. It differs from the second species by a thinner body, shorter male tail and shorter labial setae.</p

Two new nematode species of the genus &lt;I&gt;Paratrilobus&lt;/I&gt; Micoletzky, 1922 (Nematoda, Triplonchida) from the water area of Lake Baikal (Russia)

This paper describes and illustrates two new nematode species of the genus Paratrilobus Micoletzky, 1922. The species Paratrilobus tankhoyensis sp. nov. was found at the estuary of the Pereyomnaya River (water area of Lake Baikal, near the Tankhoy railway station). Paratrilobus tankhoyensis sp. nov. is most similar to P. expugnator (Tsalolichin, 1976) in the body size, but differs in the comparatively thin body, shorter and thicker tail, shorter stoma and spicules. Another new species, Paratrilobus aquaticus sp. nov., was found in Posolsk Bank (natural underwater elevation of the bottom between the southern and central basins of Lake Baikal). The species is similar to P. granulosus Gagarin &amp; Naumova, 2011 and P. ultimus (Tsalolichin, 1977) in the structure of the precloacal supplements. It differs from the former in the absence of crystalloids, a comparatively longer pharynx, longer stoma and outer labial setae as well as the absence of subterminal seta. It differs from the latter in a longer pharynx, stoma and longer outer labial setae as well as a longer and more slender tail. We also discuss diagnostic features of the males of the genus Paratrilobus.</p