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1.
PeerJ ; 8: e9037, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32377453

RESUMO

During a survey of intertidal zones at beaches on Jeju Island, two species belonging to the family Thoracostomopsidae were discovered. One new species, Enoploides koreanus sp. nov. and one known species, Epacanthion hirsutum Shi & Xu, 2016 are reported. Along with morphological analysis, mitochondrial cytochrome oxidase c subunit 1 (mtCOI) sequences and 18S rRNA sequences of the species were also obtained and used to check relative p-distance and phylogenetic positions. While most species of Enoploides have long spicules, the new species belongs to a group of Enoploides with short spicules < 150 µm). Of the seven species with short spicules, the new species is most closely related to E. disparilis Sergeeva, 1974. They both have similar body length, fairly similar sized and shaped spicules with small gubernaculum running parallel to distal end of spicule, and an index value of b. The new species can be distinguished from E. disparilis by having pre-anal supplementary organ with short conical tail, while E. disparilis lacks pre-anal supplementary organ and has a long conico-cylindrical tail. Along with the description of the new species, the genus Enoploides Ssaweljev, 1912 is bibliographically reviewed and revised. Of 45 species described to date, 27 are now considered valid, 16 species inquirendae due to inadequate descriptions and ambiguity of the material examined, along with two cases of nomen nudum. With this review, we provide an updated diagnosis and list of valid species, a tabular key comparing diagnostic characters of all valid species, and a new complete key to species. One known species, Epacanthion hirsutum Shi & Xu, 2016, is reported in Korea for the first time. The morphology agrees well with the original description provided by Shi & Xu, 2016. As they had already reviewed the genus at the time of reporting four Epacanthion species, we provide only a description, depiction, and measurements for comparison purposes.

2.
PeerJ ; 7: e8023, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31763070

RESUMO

A new species of the genus Mesacanthion Filipjev, 1927 was discovered during a survey of natural beaches of Jeju Island in South Korea. The new species Mesacanthion jejuensis sp. nov. shares general morphology of the genus such as the outer labial and cephalic setae being situated at the middle of cephalic capsule, well-developed mandibles with two columns united by a curved bar, and three equally sized and shaped teeth shorter than the mandibles. The new species belongs to a group of Mesacanthion species in which spicules are shorter than two anal body diameters. The new species is most closely related to M. pannosum, first discovered in Puget Sound, Washington, in terms of having enlarged cervical setae flap at the end of cephalic capsule, spicules which are shorter than 2 anal body diameter, both supplementary organ and gubernaculum. It can be distinguished from M. pannosum by its stronger inner labial setae, longer outer labial setae, and difference in the index value of b and c'. Along with the description of Mesacanthion jejuensis sp. nov., the genus Mesacanthion Filipjev, 1927 is bibliographically reviewed and revised. Including the new species, a total of 48 species are described within the genus; 39 which are valid; eight which are considered to be species inquirenda due to misplacement of genus and poor description; one which is considered nomen nudum. An updated diagnosis of the genus is provided along with a compiled tabular key comparing different diagnostic morphological characters of all valid species, as well as a pictorial key consisting of 21 species with spicules shorter than two anal body diameters.

3.
Zootaxa ; 4563(3): zootaxa.4563.3.6, 2019 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-31716532

RESUMO

A new species of the genus Thalassironus de Man, 1889 was discovered during several surveys of the offshore marine ecosystem in Korea. This new species belonging to the family Ironidae, Thalassironus koreanus sp. nov., shares general morphological traits of the genus such as an optically smooth cuticle, buccal cavity consisting of two parts with three movable teeth and thick cuticularized walls, six rounded lips with ten cephalic setae, slit-like amphid and short conical tail with caudal glands present. The new species is most closely related to T. bohaiensis, first discovered in the Bohai Sea, in terms of body ratio (a, b, c, c') and general morphology, but differs by its generally longer and larger body structures, cervical setae at the level of the buccal cavity, paired somatic setae distributed along the body, and longer/larger spicule. A description of Thalassironus koreanus sp. nov., diagnosis of the genus, emended pictorial key for the genus and discussion of important characteristics for the genus is provided.


Assuntos
Enoplídios , Nematoides , Animais , Ecossistema , República da Coreia
4.
Zootaxa ; 4098(2): 333-57, 2016 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-27394589

RESUMO

One new and one known species of the family Comesomatidae Filiepjev, 1918 were collected from marine sediments in the East Sea, Korea. Cervonema donghaensis sp. nov. is related to C. proximamphidum Tchesunov, 2000 and C. chilensis Chen & Vincx, 2000 but differs from them by the presence of the gubernaculum and by having outer labial setae and cephalic setae of unequal length. It differs from C. proximamphidum by having a rather shorter tail and the shape of the posterior widening of the pharynx, which has distinct muscular striation. Cervonema donghaensis sp. nov. differs from C. chilensis in body length, higher de Man's ratio c, and having a shorter cylindrical portion of the tail. Cervonema deltensis Hope & Zhang 1995 is considered as a junior synonym of C. tenuicauda (Schuurmans Stekhoven, 1950) Wieser, 1954. Specimens of Laimella filipjevi Jensen, 1979 from East Sea, Korea largely agree with the original description of Jensen (1979) of nematodes from the Western Baltic Sea, except for slight differences in length of cephalic setae and spicules. It also coincides well with the redescription of L. filipjevi by Tchesunov (2000) based on specimens from the White Sea. Pictorial keys for the identification of valid species in the genera Cervonema Wieser, 1954 and Laimella Cobb, 1920 are given.


Assuntos
Adenofórios/classificação , Adenofórios/anatomia & histologia , Adenofórios/crescimento & desenvolvimento , Adenofórios/isolamento & purificação , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Animais , Tamanho Corporal , Ecossistema , Feminino , Sedimentos Geológicos/parasitologia , Masculino , Oceanos e Mares , Tamanho do Órgão , República da Coreia
5.
Zootaxa ; 4121(4): 383-411, 2016 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-27395231

RESUMO

Morphological descriptions of three "walking nematode" species found for the first time in the White Sea are presented. Draconema ophicephalum (Claparède, 1863) (Draconematidae) and Epsilonema steineri Chitwood, 1935 (Epsilonematidae), both known from insufficient material and females only, are re-described and problems of their taxonomic identification as well as species compositions of respective genera are discussed. The new species Prochaetosoma marisalbi sp. n. (Draconematidae) differs from other Prochaetosoma species except P. longicapitatum (Allgén, 1935) in that the pharyngeal bulb lumen is not cuticularised, from P. longicapitatum by shape of body and rostrum, greater number of cephalic adhesive tubes, and from P. maertensi Decraemer, 1989 by having a relatively longer tail, fewer anterior adhesive tubes and longer spicules, besides lacking cuticular thickening in the pharyngeal bulb. Draconema hoonsooi, D. youngeouni, P.rochaetosoma beomseomense, P. brevicaudatum, P. byungilli, P. cracense, P. saheungi, P. sujungi, P. supseomense erected by Rho & Min (2011) are considered as invalid species while Prochaetosoma arcticum, P. lugubre and Epsilonema cygnoides are assumed as species inquirenda. From a phylogenetic tree based on the 18S rRNA gene, all three White Sea species adjoin to unidentified species of their respective genera.


Assuntos
Adenofórios/classificação , Adenofórios/anatomia & histologia , Adenofórios/genética , Adenofórios/crescimento & desenvolvimento , Distribuição Animal , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Animais , Tamanho Corporal , Feminino , Masculino , Oceanos e Mares , Tamanho do Órgão , Filogenia , Água do Mar/parasitologia
6.
Zootaxa ; 3872(1): 57-74, 2014 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-25544071

RESUMO

Four new species of the genus Litinium are described from mangroves and from deep sea. The genus Litinium now includes ten valid species. An emended generic diagnosis and a pictorial guide for species identification are given. Litinium quangi sp. n. and L. curticauda sp. n., both found in mangroves of South Vietnam, are morphologically similar and differ from other congeneric species in body size, having short anterior setae, ovoid amphideal fovea and a short rounded tail. Litinium quangi differs from L. curticauda in the number of midventral preanal supplementary setae (one in L. quangi and two in L. curticauda) and relative tail length (c' 1.12-1.63 in L. quangi and 0.83-0.94 in L. curticauda). Litinium abyssorum sp. n. and L. profundorum sp. n., both collected from the Angola Basin, South-East Atlantic Ocean, at depth 5400 m, are also morphologically similar and differ from other species of the genus by having a smaller body and relatively large amphideal fovea with deep invagination of the anterior edge. Litinium abyssorum differs from L. profundorum in the number of midventral preanal setae (two in L. abyssorum, one in L. profundorum), relative tail length (c' 3.61 in L. abyssorum and 1.17 in L. profundorum) and L. abyssorum has unequal spicules.


Assuntos
Enoplídios/classificação , Distribuição Animal , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Animais , Tamanho Corporal , Ecossistema , Enoplídios/anatomia & histologia , Enoplídios/crescimento & desenvolvimento , Feminino , Masculino , Tamanho do Órgão
7.
PLoS One ; 6(5): e20094, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21629829

RESUMO

The Gollum Channels and Whittard Canyon (NE Atlantic) are two areas that receive high input of organic matter and phytodetritus from euphotic layers, but they are typified by different trophic and hydrodynamic conditions. Sediment biogeochemistry was analysed in conjunction with structure and diversity of the nematode community and differences were tested between study areas, water depths (700 m vs 1000 m), stations, and sediment layers. The Gollum Channels and Whittard Canyon harboured high meiofauna abundances (1054-1426 ind. 10 cm(-2)) and high nematode diversity (total of 181 genera). Next to enhanced meiofauna abundance and nematode biomass, there were signs of high levels of organic matter deposition leading to reduced sedimentary conditions, which in turn structured the nematode community. Striking in this respect was the presence of large numbers of 'chemosynthetic' Astomonema nematodes (Astomonema southwardorum, Order Monhysterida, Family Siphonolaimidae). This genus lacks a mouth, buccal cavity and pharynx and possesses a rudimentary gut containing internal, symbiotic prokaryotes which have been recognised as sulphur-oxidising bacteria. Dominance of Astomonema may indicate the presence of reduced environments in the study areas, which is partially confirmed by the local biogeochemical environment. The nematode communities were mostly affected by sediment layer differences and concomitant trophic conditions rather than other spatial gradients related to study area, water depth or station differences, pointing to small-scale heterogeneity as the main source of variation in nematode structure and function. Furthermore, the positive relation between nematode standing stocks, and quantity and quality of the organic matter was stronger when hydrodynamic disturbance was greater. Analogically, this study also suggests that structural diversity can be positively correlated with trophic conditions and that this relation is tighter when hydrodynamic disturbance is greater.


Assuntos
Invertebrados , Nematoides , Animais , Oceano Atlântico , Biomassa , Monitoramento Ambiental
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