scholarly journals Two New Marine Free-Living Nematodes from Jeju Island Together with a Review of the Genus Gammanema Cobb 1920 (Nematoda, Chromadorida, Selachinematidae)

Diversity ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 19 ◽  
Author(s):  
Alexei Tchesunov ◽  
Raehyuk Jeong ◽  
Wonchoel Lee

In the context of exploration of meiofauna in a sandy intertidal zone of Jeju Island (South Korea), over 70 nematode species are identified, some which have been proven to be new for science. Two new free-living marine nematode species of the family Selachinematidae (Chromadorida, Selachinematidae, Choniolaiminae) are described from the intertidal sandy sediments of Jeju Island (South Korea). Gammanema okhlopkovi sp. n. is closest to Gammanema anthostoma (Okhlopkov, 2002) and differs by having longer cephalic setae (8.5–19 μm in G. okhlopkovi versus 6–7.5 μm in G. anthostoma) and by the presence of precloacal supplementary organs. The genus diagnosis of Gammanema is updated. The genus includes fourteen valid species, while three species are considered species inquirendae due to incomplete diagnoses and illustrations impeding their correct recognition. An annotated list of valid and invalid Gammanema species is provided. A pictorial key for valid Gammanema species is constructed, which consists of two components: (1) simplified images of heads, and (2) a table summarizing most of the significant measured and numeric characters between species. Latronema obscuramphis sp. n. differs from its related species Latronema aberrans (Allgén 1934), Latronema annulatum (Gerlach, 1953), and Latronema spinosum (Andrássy, 1973) by body size, number of supplementary organs, tail shape, length of spicules, and cuticle ornamentation.

Author(s):  
Gustavo Fonseca ◽  
Wilfrida Decraemer

The family Monhysteridae is characterized by 17 valid genera, seven of which are known to be free-living, inhabiting marine sediments. In total, 70 valid marine species are ascribed to these seven genera. Overall, the family is characterized by a confused taxonomic history with a large list of synonyms and species inquirendae. The taxonomic problem is not restricted to the old literature, but inconsistencies also appeared in recent studies. The aim of this study is to show the most important diagnostic characters to identify each genus and provide taxonomic tools for species identification. Dichotomous-keys and illustration-guides are attempted for the marine monhysterid species. For the family and each subfamily, tribe and marine genus a brief historical background, diagnosis and a list of valid species is provided. Hereby, we propose to transfer eight species of the genus Thalassomonhystera to the genus Monhystrella.


Zootaxa ◽  
2017 ◽  
Vol 4306 (4) ◽  
pp. 478 ◽  
Author(s):  
ALEXEI V. TCHESUNOV

Three nematode species of the genus Syringolaimus (Enoplida, Ironidae) were found in the Angola Basin (south-east Atlantic Ocean) at depths of almost 5500 m. One of them is described as new for science and the other two were initially recorded from the deep sea off the Brazilian coast and are redescribed here. Syringolaimus elegans sp. n. differs from all other species of Syringolaimus by a slimmer body (a=99 vs. 30–73) and from all species except S. ingens (nom. nud.) by its greater body length (2718 μm vs. 760–1750 μm), longer buccal cavity (79 μm vs. 28–58 μm), and longer terminal pharyngeal bulb (70 μm vs. 53 μm). All the Syringolaimus species together make up from 0.75 to 2.82% of all nematode individuals from all samples. Diagnoses of Syringolaimus annae Lima et al., 2009 and S. smolae Lima et al., 2009 are updated. An annotated list of Syringolaimus species is provided; the species annae, elegans, filicaudatus, loofi, magdae, renaudae, smolae, striatocaudatus and taniae are considered as valid, while brevicaudatus, caspersi, lichenii, marisalbi, smarigdus and venustus as species inquirendae, and gladiatus, ingens, nitidus and venustus as nomina nuda. Diagnostic characters and problems of species identification are discussed. 


Author(s):  
Daniel Leduc

Two new species of the family Trefusiidae, viz., Trefusia piperata sp. nov. and Trefusialaimus idrisi sp. nov., are described from the crest of the Chatham Rise, Southwest Pacific Ocean (350 m water depth). The present study provides the first species records for this family in the region. Trefusia and Trefusialaimus comprise twenty and three valid species, respectively. A key to males of Trefusia is provided.


Zootaxa ◽  
2013 ◽  
Vol 3609 (3) ◽  
pp. 274-290 ◽  
Author(s):  
DANIEL LEDUC ◽  
DOMINICK VERSCHELDE

One new genus and two new species of the family Desmodoridae are described from the upper continental slope of New Zealand, at 350–1240 m water depths. Onepunema gen. n. is characterised by a striated head capsule, small buccal cavity without teeth, and presence of two testes. Onepunema gen. n. can be differentiated from all other genera of the family by the presence of two testes, which is an exception to the holapomorphic character (i.e. monorchic males) of the Desmodoroidea. Onepunema enigmaticum gen. et sp. n. shares characters typical of the subfamilies Spiriniinae (small buccal cavity without distinct teeth) and Desmodorinae (presence of head capsule). Onepunema gen. n. is placed within the Desmodorinae based on the latter trait, which is never found within the Spiriniinae. The type species, Onepunema enigmaticum gen. et sp. n., is characterised by the presence of two laterodorsal and two lateroventral rows of pores with conspicuous ducts, slender pharynx with rounded terminal bulb, presence of two types of cells in intestinal epithelium, and presence of four or five pre-cloacal supplements consisting of thickened areas of cuticle in males. The genus Pseudonchus is recorded for the first time from the deep sea (1240 m water depth) and from the New Zealand region. Pseudonchus virginiae sp. n. is characterised by its stout body, short cephalic setae, monospiral amphideal fovea, short arcuate spicules with capitulum, five regularly-spaced precloacal setae, and short conical tail. A key to all known valid species of the genus Pseudonchus is provided.


Zootaxa ◽  
2008 ◽  
Vol 1866 (1) ◽  
pp. 151 ◽  
Author(s):  
ALEXEI V. TCHESUNOV

Three new nematode species were found in the Angola Basin (south-east Atlantic Ocean) at depths of about 5500 m. Paracyatholaimus diva sp. nov. (Cyatholaimidae) is characterised by outer labial and cephalic setae of about 3–5 μm, multispiral amphidial fovea with six turns in males and four turns in females situated at the level of the dorsal tooth, buccal cavity armoured with only one prominent dorsal tooth, tail consisting of anterior conical and posterior slender cylindrical half portions, and six preanal midventral setose supplementary organs. Paracyatholaimus diva sp. nov. is most similar to Paracyatholaimus rotundus Gerlach, 1964 but differs by slightly longer body (936–1176 μm versus 705 μm), tail shape (with clearly narrowed posterior half versus conical), six versus four supplementary organs of different shape. The genus Paracyatholaimus Micoletzky, 1923 is briefly reviewed. The genus now includes twenty-four valid species. Five species are considered as species inquirendae, mainly because of inadequate type material lacking adult stages and/or incomplete descriptions. A pictorial guide for identification of the valid species of Paracyatholaimus is provided. Pomponema proximamphidum sp. nov. shares subapical position of the amphidial fovea and distinct lateral differentiation of the somatic cuticle with five Pomponema species: P. concinnum Wieser, 1954, P. corniculata Gourbault, 1980, P. mirabile Cobb, 1917, P. multipapillatum Filipjev, 1922 and P. stomachor Wieser, 1954 but differs from them by tail length, longer posterior cylindrical portion of the tail, relative width of the amphidial fovea, position of the ventral pore and lesser number of supplementary organs. Desmodora striatocephala sp. nov. is well characterized by a combination of very large amphidial fovea occupying nearly the entire lateral surface of the cephalic capsule and thickened midventral preanal cuticle with a few supplementary papillae inserted therein in males. D. striatocephala sp. nov. differs from related species D. cuddlesae Inglis, 1963 and to some lesser degree with D. inflexa Wieser, 1954 with shorter body, relative tail length, bigger size of the amphidial fovea and lesser number of supplementary papillae.


Zootaxa ◽  
2013 ◽  
Vol 3608 (7) ◽  
pp. 547-560 ◽  
Author(s):  
VLADIMIR G. GAGARIN

Specimens of four new nematode species of the family Comesomatidae were isolated from the sediments of littoral zone of South China Sea at the coast of Vietnam and described and illustrated. Sabatieria curvispiculata sp. n. is characterized by the long and slender tail, short cephalic setae and strongly curved spicules in males. Setosabatiera orientalis sp. n. is close to S. australis Riera, Nunez, Brito, 2006, but differs from it in the comparatively shorter and more slender tail, small-er number of amphidial fovea turns, greater number of precloacal supplements in males and shape and structure of spic-ules. Dorylaimopsis intermedia sp. n. is morphologically closest to D. mediterranea Grimaldi-de Zio, 1968 and D. magellanense Chen, Vincx, 1968, but differs from both species in the longer outer labial setae and absence of precloacal supplements in males. D. brevispiculata sp. n. is similar to D. turneri Zhang, 1992 and D. coomansi Muthumbi, Soetaert, Vincx, 1977, but differs from both species in the shape of outer labial sensillae and absence of precloacal supplements in males. A pictorial key for determination of valid species in the genus Setosabatieria Rouville, 1903 is given.


Zootaxa ◽  
2009 ◽  
Vol 1998 (1) ◽  
pp. 1-170 ◽  
Author(s):  
ILSE BARTSCH

At the end of 2007, the family Halacaridae, superfamily Halacaroidea, included 1118 valid species in 63 genera. The genera and the number of species (in parentheses) are: Acanthohalacarus (1), Acanthopalpus (2), Acarochelopodia (8), Acaromantis (11), Acarothrix (5), Actacarus (24), Agaue (42), Agauides (2), Agauopsis (85), Anomalohalacarus (19), Arenihalacarus (1), Arhodeoporus (31), Astacopsiphagus (1), Atelopsalis (7), Australacarus (5), Bathyhalacarus (12), Bradyagaue (17), Camactognathus (3), Caspihalacarus (1), Coloboceras (3), Colobocerasides (2), Copidognathides (3), Copidognathus (359), Corallihalacarus (1), Enterohalacarus (1), Halacarellus (47), Halacaroides (2), Halacaropsis (5), Halacarus (75), Halixodes (3), Hamohalacarus (1), Himejacarus (1), Isobactrus (26), Limnohalacarus (13), Lobohalacarus (6), Lohmannella (36), Metarhombognathus (2), Mictognathus (3), Parasoldanellonyx (3), Parhalixodes (2), Pelacarus (1), Peregrinacarus (2), Phacacarus (1), Porohalacarus (2), Porolohmannella (1), Rhombognathides (6), Rhombognathus (103), Ropohalacarus (1), Scaptognathides (11), Scaptognathus (30), Simognathus (45), Soldanellonyx (9), Spongihalacarus (1), Stygohalacarus (1), Thalassacarus (1), Thalassarachna (14), Thalassophthirius (1), Troglohalacarus (1), Tropihalacarus (2), Werthella (10), Werthelloides (1), Winlundia (2), and Xenohalacarus (1). More than 1000 species live in marine and brackish water and almost 60 species exclusively in fresh or oligohaline to mesohaline brackish water (< S18‰). The checklist presents names used for halacarid genera and species of the world, names recognized as valid, synonyms, nomina nuda, names of species inquirendae and species erroneously attributed to the family Halacaridae. All valid species are supplemented with distributional data, namely, biogeographical provinces, depth zones and habitats, and references of descriptions of genera and species.


Zootaxa ◽  
2021 ◽  
Vol 5020 (1) ◽  
pp. 130-140
Author(s):  
ALEXEY V. TCHESUNOV ◽  
RAEHYUK JEONG ◽  
WONCHOEL LEE

As a part of the study of marine nematofauna of a sandy intertidal zone of Jeju Island (South Korea), a number of species have been proven as new for science. Here a new species representing a new genus of the family Microlaimidae (Chromadorea), Jejulaimus sinyangensis gen. n., sp. n. is described. The new monotypic genus is characterized by head set off abruptly from the body; anterior sensilla pattern 6+10, where six outer labial setiform sensilla together with four longer cephalic setiform sensilla are integrated in a common crown; pharyngostoma armed with a dorsal tooth and surrounded by convex muscular pharyngeal tissue, forming an anterior pharyngeal bulb which is distinctly set off from the rest of the pharynx; terminal pharyngeal bulb oval; ventral pore and ampulla of the excretory-secretory gland situated just posterior to the nerve ring; an only anterior testis present. The new genus bears some resemblance to the genera Bolbolaimus, Pseudomicrolaimus and Spirobolbolaimus in having an anterior pharyngeal bulb and in the position of the ventral pore of the excretory/secretory gland, but differs from them by anterior sensilla pattern 6+10, absence of subventral teeth in buccal cavity, and monorchic condition of male reproductive system.  


2019 ◽  
Vol 178 ◽  
pp. 102160 ◽  
Author(s):  
Vladimir V. Mordukhovich ◽  
Alexandr A. Semenchenko ◽  
Natalya P. Fadeeva ◽  
Julia K. Zograf

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