New Species Of Free-living Nematodes Research Articles

A New Species of Free-Living Nematode (Enoplida: Enchelidiidae) from the Mangrove Wetlands of China

A new species, Belbolla mangrove sp. nov., isolated from the mangrove wetlands of Fujian and Zhejiang Provinces in China, is described and illustrated. Belbolla mangrove sp. nov. is characterized by a pharynx with four bulbs, a small gubernaculum with a short dorsocaudal apophysis, four weakly developed precloacal supplements, a conico-cylindrical tail with a terminal spinneret, and the absence of terminal setae. This new species differs from B. vietnamica by the absence of ocelli and the blunt and rounded proximal ends of the spicules. The 18S rDNA GenBank accession numbers of B. mangrove sp. nov. are provided.

<i>Hofmaenneria baikalensis</i> sp. n. and <i>Paratrilobus longisomus</i> sp. n. (Nematoda) from Lake Baikal

Illustrated descriptions of two new species of free-living nematodes Hofmaenneria baikalensis sp. n. and Paratrilobus longisomus sp. n. found in the Lake Baikal (Russia) are given. Hofmaenneria baikalensis sp. n. is close to H. keoladeoensis Khan et al., 2005, H. niddensis (Skwarra, 1921) Schneider, 1940 and H. sitnikovae Gagarin, Naumova, 2010. It differs from these three species in a presence of crystals in the body cavity and presence of three oval cardial glands. Paratrilobus longisomus sp. n. is close in the body size to P. expugnator (Tsalolichin, 1976) and P. rapis Gagarin, 1991 but it has a relatively shorter and slenderer tail and presence of subterminal seta at the tail end.

Six new species of free-living nematodes (Nematoda: Enoplida) from deep-sea cold seeps on Hikurangi Margin, New Zealand.

Little is known about the taxonomy of deep-sea nematode species inhabiting cold seep habitats. An opportunity to characterize the nematode species communities of New Zealand cold seeps was provided by a 2019 research voyage to New Zealand's Hikurangi Margin, during which macrofauna cores were obtained at two seeps at approximately 1,250 and 2,000 m water depth. Here, six new species of the orderEnoplida are described. Metacylicolaimus catherinae sp. nov. represents the first record of the genus for the New Zealand Exclusive Economic Zone and for the deep sea globally. Halalaimus talaurinus sp. nov., Thalassoalaimus duoporus sp. nov. and Crenopharynx crassipapilla sp. nov. are only the second species of their respective genera to be described/recorded from New Zealand waters, and Oncholaimus adustus sp. nov. is the eighth species of the genus to be recorded from the region. Rhabdodemania zealandiaensis sp. nov. was among the most abundant and widespread species found at the Hikurangi Margin seep sites. A few specimens had been found in a previous ecological study of meiofaunal nematode communities on Chatham Rise, a submarine ridge south of Hikurangi Margin. It is possible that this species has a preference for seep environments due to elevated food availability, however it does not seem to be exclusively found in seeps. We find no evidence for an affinity between nematode seep communities in New Zealand and elsewhere, which is consistent with the high variability in nematode community observed to date among regions. Ongoing work on the ecology and distribution of nematode communities at the Hikurangi Margin seep sites will help determine spatial patterns in abundance and species distributions in more detail, including the identification of any species/taxa with affinities with seeps.

Three new species of free-living marine nematodes from the central basin of the South China Sea

ABSTRACT Three new species of free-living nematodes were discovered in the central basin of the South China Sea and are described here as Elzalia longicaudata sp. nov., Minolaimus distalamphidus sp. nov. and Setoplectus minor sp. nov. Elzalia longicaudata sp. nov. is characterised by a longer tail and longer buccal cavity relative to other members of the genus; presence of a circle of four cervical setae; spicules slender and long, which curve as the body bends; and simple gubernaculum with only one section of dorsal apophysis. Minolaimus distalamphidus sp. nov. can be distinguished from congeners by the male having lateral differentiation with six longitudinal rows of large dots; multispiral amphideal fovea with 8.5 turns; pharynx cylindrical without bulb; spicules slightly arcuate; gubernaculum rod-like without apophysis; about 17 sucker-shaped precloacal supplements; and tail conical with long filiform posterior portion. Setoplectus minor sp. nov. differs from its congeners by small body size, anterior third of pharyngeal region attenuated; cephalic setae 2 µm long; amphidial aperture circular or oval; tail elongated conical; male with a single papilliform precloacal supplement. Updated identification keys for species of the three genera are also given. http://www.zoobank.org/urn:lsid:zoobank.org:pub:623BC44A-A07F-420E-AA41-271CF85F64C6

Description of Two New Species of Free-Living Nematodes (Nematoda) from Vietnam

An illustrated description of two free-living nematode species—Leptolaimoides brevicaudatus sp. n. and Paramonhystera affinis sp. n.—from the water bodies of Vietnam is presented. L. brevicaudatus is similar to L. thermastris (Lorenzen, 1966); L. gangioensis Hoang Lai-Phu et al., 2009; and L. asiaticus Gagarin, Nguyen Vu Thanh, 2005 in regards to body size, but differs from these species by a shorter and less slender body, longer spicules, and the absence of precloacal supplements in males. Paramonhystera affinis sp. n. is morphologically similar to P. parabutschlii (Timm, 1961) and P. levicula (Lorenzen, 1972), but it has shorter and sparse somatic setae, six outer labial setae (versus four outer labial setae in both compared species), and shorter spicules.

Two new species of free-living nematodes (Nematoda) from Vietnam

Two new species of nematodes from the families Monhysteridae and Tobrilidae are described. Nematodes were collected from small forest ponds in North and Central Vietnam. Monhystera vietnamica sp. nov. differs from morphologically close M. uncigubernaculum Zedan, Jacobset et Geraert, 1989 mainly in longer vagina and rectum, from M. rolandi Khan et Tahseen, 2006 in longer cephalic setae and presence of ocellus. Brevitobrilus larae sp. nov. differs from morphologically close B. orientalis Tsalolikhin, 2013 mainly in longer body and longer and thinner, not hornlike cephalic setae. The genus Brevitobrilus was previously represented in Vietnam only by the species B. stefanskii (Micoletzky, 1925).

Four new species of free-living nematodes from shallow continental shelf of Portugal.

Free-living marine nematodes of continental shelf of Portugal were studied through the goals of the Marine Biodiversity Information System Project (M@rbis 2015). Four species unknown to science and belonging to the families Axonolaimidae, Chromadoridae, Desmodoridae and Xyalidae are described. Besides Hypodontolaimus golikovy, Hypodontolaimus portuguese sp. n. is the only species in this genus which lacks precloacal supplements and gubernaculum but differs from the former mainly in cephalic setae length and amphidial fovea features. Metachromadora aliusa sp. n. doesn't have a unique diagnostic character, differing in many aspects from the other species of the genus instead, mainly teeth number in the buccal cavity, size of the cephalic setae and the amphidial fovea, velum presence in the spicules, number and shape of the precloacal supplements. The main character of Odontophora sinapophysis sp. n. is the absence of apophysis in the gubernaculum. Stylotheristus multipapillatus sp. n. is characterized by the presence of precloacal supplements (papilliform) and the gubernaculum formed by only a piece.

New Genus and Two New Species of Free-Living Nematodes (Nematoda, Monhysterida) from Artificial Reservoirs in Vietnam

Descriptions and illustrations are presented for a new genus and two new species of free-living nematodes found in sediments of four artificial reservoirs for shrimp aquaculture. Paradaptonema gen. n. is morphologically close to Daptonema Cobb, 1920, but it has three glands around cardia that are absent in Daptonema, as well as a peculiar structure of the reproductive apparatus in males. Paradaptonema securum gen. n., sp. n. is characterized by a finely annulated cuticle, relatively long external labial setae, the presence of a postvulvar cell, and a peculiar shape of spicules and gubernacula. Thalassomonhystera longisoma sp. n. is morphologically close to Th. minor Gagarin, Nguyen Thi Thu, 2008 and Th. elegans Gagarin, Nguyen Vu Thanh, 2013, but differs from them in the length and slenderness of the body, as well as in the size of the external labial bristles and spicules.

Two New Species of Free-Living Nematodes of the Family Linhomoeidae (Nematoda, Monhysterida) from Mangrove Forests in Vietnam

An illustrated description of two species of free-living nematodes of the family Linhomoeidae Filipjev, 1922, new to science, found in the sediments of a thick mangrove forest in the Yen River, Vietnam, is presented. Desmolaimus minor sp. n. is morphologically similar to D. calvus Gerlach, 1956, but has a shorter body, two-separate internal cavity of pharynx, and setiform labial and cephalic sensilla. A review of species of the genus Desmolaimus de Man, 1888 is made, and a pictorial key to determinate valid species of this genus is provided. Terschellingia yenensis sp. n. is similar to T. lissa Timm, 1962 and T. longissimicaudata Timm, 1962. It differs from T. lissa by the presence of precloacal supplements in males, the presence of cervical setae, a longer tail, and shorter spicules; it differs from T. longissimicaudata by a comparatively longer tail, shorter spicules, and a longer dorsal apophysis of gubernaculum.

Two new species of free-living nematodes from the East China Sea

Two new species of free-living marine nematodes of the genera Hopperia and Nemanema are described from the sublittoral sediment of the East China Sea. Hopperia macramphida sp. nov. is characterized by having large amphidial fovea with five turns; arcuate spicules with enlarged proximal end and central internal lamella extending one third of spicule length from proximal end; gubernaculum with bent apophyses, six papilliform precloacal supplements; and conico-cylindrical tail with swollen tip and terminal setae. Nemanema minutum sp. nov. is characterized by relatively smaller body size in the genus; large oval amphidial fovea; conical tail; slender spicules with alae and hooked proximal end; ring-like gubernaculum; and papilliform precloacal supplements with three short setae. An updated dichotomous key is provided for the 17 species of Hopperia.

ОПИСАНИЕ НОВОГО ВИДА СВОБОДНОЖИВУЩИХ НЕМАТОД, THERISTUS GIGAS SP. NOV. (NEMATODA, MONHYSTERIDA) ИЗ ИСКУССТВЕННОГО ВОДОЕМА ВО ВЬЕТНАМЕ

Illustrated descriptions of new species of free-living nematodes Theristus gigas sp.nov., found in ground of artificial reservoir in Vietnam. Th. gigas sp. nov. morphological similar to Th. polychaetophilus Hopper, 1966, but differs from it by longer outer labial setae and cephalic setae, more close to anterior body end located vulva, longer spicules and gubernaculum and another gubernaculum structure.

New genus and two new species of free-living nematodes (Namatoda) from mangrove thickets of the Yen River Delta (Vietnam)

A new genus of nematodes, Valvaelaimoides gen. n., from the family Linhomoeidae Filipjev, 1922 has been validated. The genus is characterized by very large and circular amphidial fovea with edges strongly sclerotized, as well as a rather complex vulva structure of the pharynx bulb. The new genus includes two species: Valvaelaimoides macramphis sp. n. (type species) and Valvaelaimoides leptus sp. n. Their illustrated description has been given. V. leptus sp. n. is distinguished from V. macramphis sp. n. by a shorter body, relatively longer cephalic setae, and shorter spicules.

Two new species of free-living nematodes of the family Dorylaimidae (Nematoda, Dorylaimida) from small freshwater bodies of Vietnam

Illustrated descriptions of two new species of free-living nematodes found in sediments of small water bodies of Vietnam are presented. Laimydorus propinquus sp. n. is morphologically similar to L. papillatus Ahmad, Ahmad, 2002, but it is distinguished from it by a relatively longer and thicker body, a longer tail in females, a more anterior position of vulva, a longer prerectum in females, longer spicules, and large number of precloacal supplements in males. Ischiodorylaimus paracognatus sp. n. differs from the similar species I. cognatus Andrassy, 1983 by a longer body, relatively short pharynx, thicker cuticle, wider lip area, and shorter spicules.

Pseudolella major sp. nov. (Axonolaimidae, Nematoda) from the intertidal zone of the East China Sea

A new species of free-living nematode, Pseudolella major sp. nov. is described from the intertidal mudflats of Ximen Island in the East China Sea. Pseudolella major sp. nov. is characterized as follows: body length ~1 300 μm; short cephalic setae, 2–3 μm long; amphidial fovea loop-shaped with elongated ventral branch; ventral branch 50–60 μm long and extending past the base of buccal cavity; buccal cavity cylindrical with arching or spherical base; three heavy outwardly-curving odontia with blunt tips located at anterior of buccal cavity; pharynx short with posterior bulb; ventral gland cell elongate oval-shaped, located posterior to pharyngo-intestinal junction; excretory pore situated at the level of the middle of buccal cavity; tail conical to cylindrical; spicules arched, with double-cephalate proximal end; gubernaculum with a strong dorsal caudal apophysis.

A new species of Parodontophora (Nematoda: Axonolaimidae) from the intertidal zone of the East China Sea

This study described a new species of free-living nematode discovered in the intertidal mudflat of Ximen Island, East China Sea. The new species, designated Parodontophora longiamphidata sp. nov., was characterized by a cylindrical body with tapering extremeties; cuticle smooth without somatic setae; four short cephalic setae; cylindrical buccal cavity with six clawlike teeth at the top of stoma; pharynx cylindrical with widened base; amphidial fovea crook-shaped with elongated scalariform branch extending past level of base of pharynx and ventral gland; ventral gland cell long-oval shaped located posterior to pharyngo-intestinal junction; excretory pore at level of middle of buccal cavity; tail conico-cylindrical with enlarged tip; three caudal gland cells, male spicules arched with cephalic proximal end and tapered distal end; gubernaculum with dorso-caudal apophysis; female with two opposed outstretched ovaries; and vulva at slightly post-midpoint of body length. This new species was close to P. wuleidaowanensis Zhang, 2005 and P. polita Gerlach, 1955 in terms of long amphidial fovea branch. The newly found species was easily distinguishable from the two documented; its amphidial fovea branch (255–290 µm versus 72–106 and 125–150 µm) was obviously longer. Key to the Parodontophora species with a longer amphidial fovea branch was given.

Two new species of free-living nematodes of the genus Dorylaimoides Thorne, Swanger, 1939 from fresh waterbodies of Vietnam

Illustrated descriptions are given of two new species of free-living nematodes of the genus Dorylaimoides found in small fresh waterbodies of Vietnam. D. curvicaudatus sp. n. is morphologically similar to D. singaporensis Ahmad, Mushtaq, 2004 and D. elongatus Husain, Khan, 1968, but it has a shorter tail, longer basal widening of pharynx, different length of female prerectum, and longer spicules in males. Morphologically, D. vietnamicus sp. n. is close to D. leptidus Timm, 1964 and D. elaboratus Siddigi, 1965 but differs from both of them by a shorter odontostyle, the size of its spicules, and a smaller number of supplements in males.

Two new species of free-living nematodes (Nematoda and Chromadorea) from mangrove thicket in Vietnam

Illustrated descriptions of two new species of free-living nematodes found in the dense mangrove thicket in river estuaries of Vietnam are given. Metachromadora (Metachromadoroides) orientalis sp. n. is morphologically similar to M. (M.) zaixsi Pastor de Ward, 2004, but it has longer and thicker tail, a more anterior position of the vulva, a different shape of amphidial foveae, a larger pharyngeal basal bulb, and longer spicules, and males have differently armed tails. Morphologically, Terschellingia lutosa sp. n. is closer to T. elegans Gagarin, Nguyen Vu Thanh, 2003 and T. supplementata Tchesunov, 1978 and differs from both of them by a less slender tail, a wider body at the area of head setae, and longer spicules. An identification key to the valid species of the genus Metachromadora (Metachromadoroides) is given.

Two new nematode species, Linhystera breviapophysis and L. longiapophysis (Xyalidae, Nematoda), from the East China Sea

Two new species of free-living nematodes discovered from the sediments in the East China Sea are described: Linhystera breviapophysis sp. nov. and L. longiapophysis sp. nov. Both species possess a dorso-caudally directed gubernacular apophysis, which makes them distinctly different from the two already known species of Linhystera. Linhystera breviapophysis is characterized by a gubernacular apophysis about 3.3 μm long, the presence of a crown of cervical setae and a filiform tail. Linhystera longiapophysis is characterized by a prominent gubernacular apophysis about 10 μm long, sparse cervical setae and a long filiform tail. An emended diagnosis of Linhystera and a pictorial dichotomous key to the species are given.

ДВА НОВЫХ ВИДА РОДА LAIMYDORUS SIDDIQI, 1969 (NEMATODA, DORYLAIMIDA) ИЗ МЕЛКИХ ПРЕСНОВОДНЫХ ВОДОЕМОВ ВО ВЬЕТНАМЕ

Two new species of free-living nematodes of the genus Laimydorus (L. gigas sp. nov. and L. tenuis sp. nov.), found in the sediments of small freshwater bodies in Vietnam, are described and illustrated. Laimydorus gigas sp. nov. is similar to L. distinctus Dey, Baqri, 1986 and L. elephas Andrassy, 1988. From the former species it differs in the longer tail in females, the shorter spicules and greater number of supplements in males. From L. elephas it differs in the thinner cuticle, thinner body, comparatively longer odontostyle and comparatively longer prerectum in females. Laimydorus tenuis sp. nov. is similar to L. merogaster (Steiner, 1916) and L. pinguis Andrassy, 1988. From the former species it differs in the thinner cuticle, thinner body, shorter odontostyle, shorter spicules and smaller number of supplements in males. From L. pinguis it differs in the thinner body, shorter tail in females, another position of vulva and comparatively longer prerectum in females.

Three new species of nematodes (Nematoda: Enoplida) from coastal waters of Vietnam

Three new species of free-living nematodes of the order Enoplida from coastal shallow waters of northern Vietnam are described and illustrated. Paramesacanthion vietnamicum sp. n. is morphologically close to P. oxycephalum (Ditlevsen, 1926), P. truncum Vitiello, 1971, and P. hirsutum Warwick, 1970; however, it differs in lacking subcephalic setae and in having articulate cephalic setae in the males. Viscosia pygmaea sp. n. is morphologically similar to V. parva Kreis, 1929 but differs in having a shorter body and a shorter and thicker tail in the females. V. pygmaea is distinguished from V. megalaima (Ditlevsen, 1928) by its shorter body, longer cephalic setae, more slender tail, and the position of the vulva. Viscosia longicaudatoides sp. n. can be distinguished from V. parva and V. timmi Gagarin, Nguyen Vu Thanh, 2007 by its thinner body, longer and more slender tail, and shorter and narrower stoma. In contrast to V. timmi, it has short spicules and lacks vesicle-like cells between the gut and the longitudinal chords.