Anal Body Diameter Research Articles

A new species of the genus Discolaimus Cobb, 1913 (Qudsianematidae: Dorylaimida) from West Bengal, India with revised key to the genus

A new species of dorylaimid nematode, collected from rhizospheric soil of banana plantation (Musa paradisiaca L. cv. Kanthali) in Paschim Medinipur district of West Bengal, India is being described and illustrated. Discolaimus dhanachandi n. sp. comes close to D. affinis Loof, 1964 and D. elegans Sauer and Annells, 1985. But differs significantly in having large odontostyle, spear aperture occupying more than half of its length, prerectal and rectal length less than anal body width, asymmetrical ovary and slightly longer tail than anal body diameter. Besides, D. dhanachandi n. sp. differs from D. affinis in the values of c and V, and from D. elegans in the values of a, b and c. Species key of the genus Discolaimus is also provided.

Free-living nematodes from the deep-sea Håkon Mosby Mud Volcano, including the description of two new and three known species

Two new and three known species of the genera Aponema Jensen, 1978, Molgolaimus Ditlevsen, 1921, Sabatieria Rouville, 1903, and Terschellingia De Mann, 1888 were found at the deep-sea Håkon Mosby Mud Volcano, at a depth of 1250m, in the Norwegian Sea. Aponema ninae sp. n. is characterized by short body length, short spicules, gubernaculum with wide apophyses, which are bevelled on the top, and long narrowed tail with drop-shape thickened tip and caudal setae. The new species most resembles Aponema torosa (Lorenzen, 1973). Molgolaimus haakonmosbiensis sp. n. differs from all other species of Molgolaimus by shape and length of spicules; relations of spicule length to the anal body diameter; presence of two supplements. Spicules of the new species are short (30.5 µm), slender, twisted with amplate and excurved proximal parts. The appearance of our specimen of Sabatieria ornata fits well with the original description of Ditlevsen, 1918. Specimens of Terschellingia distlamphida Juario, 1974 also fit the original description based on nematodes sampled from the sub littoral of the German Bight. However, the Norwegian specimens have a shorter (1010 µ m vs. 1343 µ m) and thicker body (a=64.6 µ m vs. a=32.0 µm). The Håkon Mosby specimens of Terschellingia longicaudata De Mann, 1907 differ from the original description in body length and thickness: 1094 µm vs. 1429 µm, and a=22.3 µm vs. 49.0 µm correspondingly, but agree with descriptions by other authors, especially with the one by Chitwood (1951).

Three new species of free-living nematodes from inter-tidal sediments in southern New Zealand

Abstract Three new species are described from sheltered intertidal sediments of Papanui Inlet, southern New Zealand. Microlaimus falciferus n. sp. is characterised by a cuticle with two lateral alae, the presence of pores between the cephalic setae, a strongly sclerotised and non-compartmentalised mouth cavity and scythe-shaped spicules with two sub-lateral pre-cloacal setae. This is the first species of the family Microlaimidae described as having lateral differentiation of the cuticle. Microlaimus falciferus n. sp. can also be differentiated from other Microlaimus species by the presence of two types of porids, i.e., pores and short hollow setae, as all other species of the genus possess only one type of porid (when present). Aponema subtile n. sp. is characterised by its slender form, relatively long tail, presence of longitudinal bars and lateral grooves on the cuticle and groups of short setae in the pre- and post-cloacal regions. It is similar to A. torosum in the structure of the male sexual organs but differs from the latter in the following ways: higher a values (30-40 vs 17-27); longer tail (5.4-7.8 vs 4-5 anal body diam. long) and a weakly sclerotised pharyngeal bulb that is never angular in appearance. Sabatieria annulata n. sp. is most similar to the cosmopolitan species S. punctata, the main difference being the absence of punctations in S. annulata n. sp. Sabatieria annulata n. sp. also has shorter spicules (34-36 vs 41-54 μm) and shorter gubernacular apophyses (14-16 vs 20-24 μm) than S. punctata.

Heterorhabditis georgiana n. sp. (Rhabditida: Heterorhabditidae) from Georgia, USA

AbstractIn a survey of entomopathogenic nematodes in Georgia, a nematode isolate of the genus Heterorhabditis was collected from soil by the insect-baiting technique and maintained in the laboratory on last instar Galleria mellonella (L.) larvae. Morphological and molecular studies of the isolate showed that the nematode is a new species. Light and scanning electron microscopy, DNA characterisation and phylogeny were used for this description. Heterorhabditis georgiana n. sp. is morphologically similar to H. bacteriophora and can be distinguished from this species mainly by male and female characters. Sixty percent of males have three pairs of papillae in the terminal group; 40% with three papillae on one side and two papillae on the other. The tail is conoid and slightly curved ventrally. The percentage of the gubernaculum to spicule length (GS%) is similar to that of H. mexicana (56) but higher than that of H. bacteriophora and species in the indica-group and the length of the spicule relative to anal body diam. (SW%) is lower than that of H. baujardi (172 vs 182), H. indica (172 vs 187) and H. bacteriophora (172 vs 174), but higher than that of H. amazonensis (172 vs 152), H. floridensis (172 vs 157) and H. mexicana (172 vs 167). The female can be differentiated from related species by its unique vulva pattern. In phylogenetic trees of ITS and D2D3 regions, the new species and H. bacteriophora form a monophyletic group. The new species has evolved five autapomorphic nucleotide character states based on analysis of ITS, differing from its sister taxon H. bacteriophora at 29 and three aligned positions of ITS and D2D3 regions, respectively.

Two new species of the genus Elzalia (Nematoda: Monhysterida: Xyalidae) from the Yellow Sea, China

Two new species of free-living marine nematodes of the genus Elzalia, Elzalia gerlachi sp. nov. and Elzalia striatitenuis sp. nov. from the Yellow Sea, China, are described and illustrated. Elzalia gerlachi sp. nov. is characterized by relatively large body length (1540–1740 μm in males; 1510–1780 μm in females), spicules 135–160 μm (3.33–3.90 anal body diameter) and complex gubernaculum. Elzalia striatitenuis sp. nov. is characterized by rather small body size (560–660 μm in males; 570–630 μm in females), short cephalic setae 2.5 μm long (21.4–31.3% of head diameter), spicules 65–85 μm (4.06–4.67 anal body diameter) and relatively simple gubernaculum. The two new species can be distinguished from other species of the genus by length and structure of spicules and gubernaculum. Pictorial and tabular keys to the genus are given.

Taxonomy and biogeography of Molgolaimus Ditlevsen, 1921 (Nematoda: Chromadoria) with reference to the origins of deep sea nematodes

Molgolaimus is a genus of free-living marine nematodes which is found in high densities (10–35% of the total community) up to 2000 m depth. Its occurrence is often associated with organically enriched and recently disturbed areas. Currently, only 16 species have been described, mainly from shallow waters. The present study contributes 17 new species mainly from the Weddell Sea but also from the Pacific Ocean, and provides an illustrated polytomous identification key to species level. The 33 Molgolaimus species described can be identified based on just a few morphometric features: spicule length, body length, anal body diameter, tail length and pharynx length. A first insight into the biogeography of this deep sea genus at species level is presented. A comparison of morphometric characteristics between species suggests that the most similar species co-occur in the same geographical region, rather than within the same bathymetric zones or similar ecosystems separated over long distances. These observations suggest that deep sea nematodes may not have a common origin but might have derived “recently” from shallow water taxa. Therefore, global distribution of nematodes could be explained by means of palaeogeographical events.

New and known species of Dorylaimidae (Nematoda: Dorylaimida) from Arunachal Pradesh, India

AbstractFour new and six known species of dorylaim nematodes belonging to the family Dorylaimidae are described and reported from Arunachal Pradesh, India. Laimydorus vulvastriatus sp. n. is characterised by the 1.5-1.8 mm long body; lip region truncate, offset by weak depression; 35-38 μm long odontostyle; longitudinal vulva; advulval cuticular ornamentation; elongate, attenuated, female tail 5.0-6.8 anal body diam. long, and males with 11 contiguous ventromedian supplements with prerectum terminating within the range of the supplements. Laimydorus cardiacus sp. n. is characterised by the 1.8-2.16 mm long body; lip region truncate, offset by slight depression; 34.0-34.5 μm long odontostyle; longitudinal vulva; female tail dorsally hooked, 9-11 anal body diam. long, and males with 12 contiguous ventromedian supplements and prerectum terminating beyond the range of the supplements. Prodorylaimus bomdillaensis sp. n. is characterised by the 1.0-1.3 mm long body; lip region truncate, offset by slight depression; 25.0-26.5 μm long odontostyle; odontophore shorter than odontostyle; exceptionally long cardia; longitudinal vulva, and long, filiform tail. Prodorylaimus baldus sp. n. is characterised by the 1.62-1.75 mm long body; lip region with amalgamated lips and offset by slight depression; 14.5-16.5 μm long odontostyle; pore-like vulva; characteristic shape of pars refringens vaginae; female tail filiform, whip-like, 16.0-16.8 anal body diam. long; male with nine contiguous ventromedian supplements and prerectum terminating within the range of the supplements. Ischiodorylaimus paraugandanus, Mesodorylaimus chamoliensis, Amphidorylaimus flagellicauda, Thornenema baldum, T. mauritianum and Opisthodorylaimus cavalcantii are reported for the first time from Arunachal Pradesh.

Mononchina (Dorylaimida) from Western Malaysia

AbstractThe results of a survey of the mononchs found in 20 soil samples from Western Malaysia is presented. Twenty species were found, of which seven are new to science, although one of these (Iotonchulus sp. A) is not formally named as only a single female was found. Parahadronchus selangorensis n. sp. is a didelphic species over 3 mm long, the female possessing advulvar papillae. Hadronchoides maximus n. sp. differs from H. microdenticulatus by much longer body, buccal cavity and tail, and by the more posteriorly placed dorsal tooth. Miconchus parathornei n. sp. resembles M. thornei but is bisexual, the lip region is narrower and the dorsal tooth lies more anterior in the buccal cavity. Iotonchus abrahmani n. sp. is characterised by the reduced, but differentiated, posterior genital branch. Iotonchus pusillus n. sp. resembles I. chantaburensis but differs by the subacute tail terminus, absence of distinct caudal glands, and values of c and anal body diameter, and V. Mylonchulus williamsi n. sp. resembles M. incurvus in tail shape but differs from it in having much lower values of L, buccal cavity length and lip region diameter. The other species found were: Parahadronchus yuenae; Iotonchus trichurus; I. cf. trichurus; I. silvallus; I. basidontus; I. indicus; I. chantaburensis; I. cf. rinae; Iotonchulus longicaudatus; Mylonchulus brachyuris; M. minor; M. mulveyi; and Sporonchulus ibitiensis. Paramylonchulus indistinctus is proposed as a junior synonym of Mylonchulus mulveyi.

Heterorhabditis amazonensis n. sp. (Rhabditida: Heterorhabditidae) from Amazonas, Brazil

AbstractIn a survey of entomopathogenic nematodes in Brazil, a nematode isolate of the genus Heterorhabditis was found. The nematode was collected from soil by the insect-baiting technique and maintained in the laboratory on last instar Galleria mellonella (L.) larvae. Morphological and molecular studies of the isolate showed that the nematode is a new species. Light and scanning electron microscopy, DNA characterisation and phylogeny were used for this description. Heterorhabditis amazonensis n. sp. is morphologically similar to H. baujardi, H. floridensis, H. mexicana and H. indica, and can be distinguished from these species mainly by male and female characters. Fifty percent of Heterorhabditis amazonensis n. sp. males have two pairs of bursal papillae in the terminal group; 25% with two papillae on one side and one papilla on the other side and 25% with one pair of papillae. Twenty percent of the population has a curved gubernaculum. The percentage of the gubernaculum to spicule length (GS%) is lower than that of H. mexicana (50 vs 56), and the length of the spicule relative to anal body diam. (SW%) is lower than that of H. mexicana (152 vs 167) and H. baujardi (152 vs 182). The female can be differentiated from related species by its unique vulva pattern. In a phylogenetic tree, the new species, H. floridensis, H. baujardi and H. mexicana form a monophyletic group, a sister group to H. indica. The new species has evolved three autapomorphic nucleotide character states, differing from its sister taxa H. mexicana at 22, and H. baujardi at 15, aligned positions.

Ecanema ecae gen. n., sp. n. (Nematoda: Dorylaimida) from Costa Rica

AbstractEcanema gen. n. is described from natural forest in Costa Rica. The new genus is characterised by having distinctly offset lip region, separate lips with distinctly projecting labial papillae, attenuated odontostyle, pharynx rather sac-like, apparently divisible into three regions, large S1N1, distinct cardiac glands, amphidelphic female genital system, short conoid tail and supplements beginning within the range of spicules in males. The type and only species, E. ecae sp. n., is characterised by having 0.87-0.98 mm long body; 19.5-20.5 μm long odontostyle; expanded part of pharynx comprising 36-41% of total neck length; pars refringens vaginae sclerotised and about one anal body diam. long, and conoid tail with acute terminus.

Five new and two known species of the family Dorylaimidae (Nematoda: Dorylaimida) from Costa Rica

Abstract Five new and two known species of dorylaim nematodes belonging to the family Dorylaimidae are described and illustrated from Costa Rica. Prodorylaimus paraobesus sp. n. has 1.5-1.9 mm long body; lip region offset by a depression; 35-38μm long odontostyle with thick walls; 'double' guiding ring; transverse vulva and elongate-conoid, dorsally bent tail. Laimydorus esquiveli sp. n. has 1.6-2.1 mm long body; lip region offset by slight depression; 30-32μ m long odontostyle; 'double' guiding ring; longitudinal vulva; males with 12 ventromedian supplements and prerectum terminating within the range of supplements. Laimydorus tropicus sp. n. has 1.5-1.9 mm long body; lip region truncate, offset by depression; 'double' guiding ring; transverse vulva; female tail 14-15 anal body diam. long; male with ten ventromedian supplements and prerectum terminating within the range of supplements. Calcaridorylaimus andrassyi sp. n. has 1.7-1.8 mm long body; slightly offset lip region; 15μm long odontostyle; pore-like vulva and spicules with triple contour and much shorter ventral arm. Coomansinema brevicauda sp. n. has 1.3-1.6 mm long, robust body; 21-22μ m long odontostyle; transverse vulva; short conoid female tail with an elongate dorsally bent projection and male with ten ventromedian supplements. Mesodorylaimus guarani Andrássy, 1968 and Sicaguttur hooperi Carbonell & Coomans, 1986 are reported for the first time from Costa Rica.

Two new species of Sabatieria (Nematoda, Comesomatidae) from Golfo Nuevo, Chubut (Argentina)

Two new Comesomatidae species from the Gulfs of San José and San Matías, Chubut province of Argentina are described. Sabatieria flecha sp. n. is characterized by the particular shape of the dorsal distal end of the spicule, smaller spicule length (47 μm; 1.5 anal body diameter), number of weakly cuticularised supplements (12), size of amphids with two and a half turns, short body length (1260 μm), values of a (36) and b (7,8) and tail shape with 1/3 cylindrical part. Sabatieria sanjosensis sp. n. is characterized by a long body length (3000 μm), large value for a (82) and tail shape with 1/2 cylindrical part.

Heterorhabditis baujardi sp. n. (Rhabditida: Heterorhabditidae) from Vietnam and morphometric data for H. indica populations

AbstractA survey of entomopathogenic nematodes in Vietnam yielded several Heterorhabditis isolates. The majority belonged to H. indica; their morphometrics are given in this paper. Three isolates collected in forests in Backan, Ninhbinh and Kontum provinces, Vietnam are here described as a new species Heterorhabditis baujardi sp. n. The new species is distinguished from the other ten valid Heterorhabditis species by a combination of morphological, morphometrical, and DNA characters. Heterorhabditis baujardi sp. n. is morphometrically similar to H. indica, but can be separated from this species by the shape of the gubernaculum and the number of normal pairs of genital papillae. The gubernaculum of H. baujardi sp. n. with the proximal end ventrally curved resembles that of H. bacteriophora. Heterorhabditis baujardi sp. n. can be separated from this latter species by a shorter body length of infective juveniles and longer spicules, longer gubernaculum, and a higher spicule length to anal body diameter ratio of males. The canonical discriminant analysis of morphometrical characters of both infective juveniles and males failed to discriminate Heterorhabditis baujardi sp. n. from H. indica. However, the new species was easily distinguished from H. downesi, H. marelatus, H. megidis and H. bacteriophora. Heterorhabditis baujardi sp. n. was slightly separated from H. bacteriophora by variables of the infective juveniles, but was clearly distinguished by variables of the males. Cross-breeding tests using isolates of the new species and H.indica did not yield fertile progeny. Analysis of the ITS1 sequence of rDNA of H. baujardi sp. n. revealed substantial differences with other known ITS1 Heterorhabditis sequences. Phylogenetic relationships between Heterorhabditis species and the usefulness of morphological and molecular characters for identification of species from this group are discussed.

Nematodes from Rajasthan, India. 1. Six new species of Dorylaimida

AbstractSix new species of the order Dorylaimida are described from Rajasthan, India: Mesodorylaimus kauli sp. n., 1.00-1.14 mm long, odontostyle 11-13 μm, female tail convex-conoid with elongated dorsally bent tip, male with 40-42 μm long spicules and ten to 11 regularly spaced ventromedian supplements; Mesodorylaimus bhansalii sp. n., 1.07-1.33 mm long, odontostyle 11-14 μm, female tail 5.3-5.4 anal body diam. long, male with 35-37 μm long spicules and 14-15 contiguous ventromedian supplements; Kochinema farodai sp. n., 0.96-1.18 mm long, well set off lip region, amphidial apertures prominent, odontostyle 17-19 μm, guiding ring one lip region diam. (LRD) from anterior end, tail 28-32 μm long, convex-conoid with rounded terminus; Kochinema caudatum sp. n., 0.81-0.95 mm long, well set off lip region, odontostyle 35-38 μm, odontophore 36-38 μm, guiding ring 2.1 LRD from anterior end and convex conoid tail with rounded tip; Tylencholaimus nagauriensis sp. n., 0.64-0.74 mm long, characterised by having perioral region disc-like, odontostyle 8-9 μm, monoprodelphic female reproductive system and anteriorly directed vagina; Tylencholaimus annulatus sp. n., distinct from all the known species of the genus in having coarsely striated inner cuticle giving an appearance like the species of Tylenchida, characterised by L = 0.50-0.59 mm, odontostyle 10-12 μm, odontophore 13-15 μm, amphidelphic female reproductive system and convex-conoid tail with rounded tip.

New and little known Nematodes (Monhysteroida, Nematoda) from the Strait of Magellan and the Beagle Channel (Chile)

Six species of Monhysteroida are described from the Strait of Magellan and the Beagle Channel, Chile. Three species of which, Sabatieria heipi n. sp., Paramonhystera geraerti n. sp. and Siphonolaimus smetti n. sp., are new to science. Sabatieria heipi n. sp. is characterised by a body length of 1529–1934 μm, cuticle punctuations with lateral differentiation; cephalic setae 5 μm long, amphids spiral with 4.0–4.2 turns, 10–11 μm in diameter; spicules 76 μm (2.1 anal body diameter), with a 6 μm projection in the ventral distal extremity, 11 minute precloacal supplements; tail 3.7–4.7 anal body diameter (abd) long with enlarged tip. Paramonhystera geraerti n. sp. is characterised by a body size of 705–767 μm; head diameter 12 μm, the cephalic setae 6 μm; amphids circular, 9–10 μm in diameter; spicules slender 108–116 μm (5.6 abd) long, 5 precloacal supplements; and tail 4.0–5.2 abd. Siphonolaimus smetti n. sp. is characterised by the long spear (40–45 μm), head diameter 11–12 μm, amphids circular, 12–13 μm in diameter or 50–57% of corresponding body diameter; the spicules 55 μm and 1.5 abd; tail conical, 2.8 abd (males) and 4.0 abd (females) long. Three other species, i.e. Metacomesoma cyatholaimoides Wieser, 1954, Paramonhystera biforma Wieser, 1956 and P. megacephala (Steiner, 1916) are redescribed. A key of all known species of Paramonhystera is proposed.

Three species of Tobrilidae (Nematoda: Enoplida) from Li River at Guiling, China

Eutobrilus annetteae Joubert & Heyns, 1979 with its male reported for the first time, Semitobrilus pellucidus (Bastian, 1865) Tsalolichin, 1983, and Epitobrilus allophysis(Steiner, 1919) Tsalolichin, 1996 are described from the Li River at Guiling, China. The male of Eutobrilus annetteae is characterized by lots of crystalloids inside body, almost straight spicules about one anal body diameter long and seven equally sized supplements. Semitobrilus pellucidus from Guiling shows large variation in body width, position of amphids, form of buccal cavity, distance between denticles, direction of vagina, arrangement of oocytes, and shape of eggs. It is different from other populations in its shorter cephalic setae, less than 60% of head width, in its shorter tail and smaller c′ value. In males, there are 6–9 supplements, reduced and irregulary spaced. Epitobrilus allophysisis characterized by its labial setae longer than 50% of head width, small, posteriorly located ovoid amphid, single egg occupying whole space of uterus and blunt tail tip.

Nematodes from the Strait of Magellan and the Beagle Channel (Chile): description of four new species of the Comesomatidae.

Four nematode species of the Comesomatidae from the Strait of Magellan and the Beagle Channel, Chile, are described as new to science. Comesoma hermani n. sp. can be separated from similar species, Comesoma bermudense Jensen & Gerlach, 1977, Comesoma minimum Chitwood, 1937 and Comesoma chilense Jensen & Gerlach, 1977 by the difference of body length, cephalic setae length, the ratio of the subcephalic setae to cephalic setae length and the ratio of spicule to anal body diameter. Dorylaimopsis magellanense n. sp. is identified by the lateral differentiation of 3–4 longitudinal rows of enlarged dots, the curved spicules are prominently jointed and with a ventral protrusion. Hopperia beaglense n. sp. could be easily recognised by both the rounded tail tip and anterior head end which differs from all the species of this genus except H. dorylaimopsoides (Allgen, 1959), which has, however, a smaller de Man ratio 'a' and reflexed ovaries. Hopperia arntzi n. sp. has a shorter body length which differs from the closest species, Hopperia americana Ward, 1984 and Hopperia muscatensis Warwick, 1973. Furthermore, the de Man ratio 'a' is different between our specimens and the other two species. An identification key to all known species of the genus Hopperia is provided.

A new freshwater species ofTheristusfrom South West Africa/Namibia (Nematoda: Xyalidae)

Theristus tessae n. sp. is described from the Fish River in South West Africa/Namibia. The new species is characterized by a slender, cylindroid body, outer labial setae slightly shorter than lip region diameter, amphideal fovea one third corresponding body diameter, elongate-conoid tail equal to about three fourths the vulva-anus distance, absence of posterior uterine sac. The spicules are equal, slightly bent and barely longer than anal body diameter. T. tessae n.sp. is compared with the cosmopolitan Theristus agilis (de Man, 1880) as well as with all other known athallasic species.

Two New Species in the Family Tylenchidae (Nematoda) From Iran, With a Key To Psilenchus De Man, 1921

Two new species Psilenchus iranicus n. sp. and Tylenchus cerealis n. sp. are described and illustrated from soil samples from Iran. P. iranicus can be differentiated by the striated lip region, the presence of a postanal intestinal lobe 1.3 to 1.6 anal body-diameters long, the presence of 3 to 4 small separate cells at the level of the rectum, the structure of the lateral fields (in the female) and by the length and shape of the spicules. T. cerealis is distinctive with an open c shape on death, a very short tail with rounded terminus, a very short post-uterine branch and a posteriorly placed vulva (75-78%). A key to the present 11 species of Psilenchus is given.

Three New Species of Carcharolaimus (Nematoda: Dorylaimidae)

Carcharolaimus taurus n. sp., about 1.25 mm long, with vulva at 52-53%, has a cuticularised labial framework of 6 sectors, and blunt conoid tail longer than the anal body diameter. The male has 7 ventromedian supplements. C. multicostatus n. sp., about 1 mm long, with vulva at 53-57%, has a cuticularised labial framework with 48 ribs, blunt conoid tail equal in length to the anal body diameter. C. lucidus n. sp., about 1.7 mm long, with vulva at 51-55%, has a cuticularised labial framework of 12 sectors with denticles on the walls, blunt conoid tail equal in length to the anal body diameter; male with 5 to 7 ventromedian supplements. A small muscular bulb is present in the anterior part of the oesophagus of each of these species, most strongly developed in C. multicostatus.