Taxonomic diversity in sewage nematodes of Aligarh, North India

A checklist is given of about 50 species of aquatic and semi-aquatic species of nematodes collected from sewage drains of Aligarh and adjoining districts, Uttar Pradesh, India.. The total nematode density as well as the species diversity varied in samples from the different localities. The relative counts of the different trophic groups revealed the abundance of the colonizer bacteriophagous species indicating decomposition to be the main energy channel in the perturbed and contaminated environment. The species diversity and the maturity index were markedly low in sewage waters compared to irrigation canal waters

Chemo-oriented sex attraction in a plant parasitic nematode, Hirschmanniella oryzae

During the present observations on the sex attraction behaviour of H. oryzae it was observed that both the sexes produced attractants which resulted in a mutual response towards each other. Males of H. oryzae were more responsive than females. There was no attraction of males towards male attractants and females towards female attractants. The distance of nematode inoculation and the period of nematode exposure to attractants influenced the degree of attraction. Significant correlations were observed between the attraction (Mean Score) and the period of nematode exposure to attractants

Description and developmental biology of Teratorhabditis andrassyi n. sp. (nematoda : Rhabditida)

Teratorhabditis andrassyi n. sp. has 58-77 p.m long spicules fused at lips and bursal papillae arranged as 2 + 4 + 1 + 3. It is closely related to T. mariannae Farkas, 1973 and T. rovinjensis (Sudhaus, 1974) Andrassy, 1983 but differs from both in the length of spicules, the extent of their fusion and in the arrangement of bursal papillae. T. andrassyi n. sp. is amphimictic with a high reproductive potential. Fertilization is internal with external embryonic development. The lime taken from egg laying to hatching varies from 12-14 h at 29-30". Juvenile stages show a high degree of variability in body lengths. Ratios a, b, and c are not significant for their differentiation but the number of genital primordial nuclei along with some allometric ratios (body length anus position from anterior end; tail length/position of primordium from anterior end and tail length/anus position) are important. Primordial nuclei multiply even during active stages besides the moulting. The flexure in gonad is formed at the time of the fourth or final moulting in females but at the third moulting in males. Total duration of life cycle is only 3-4 days at 29-30"

Two new species of Chronogaster Cobb (nematoda: Araeolaimida)

Chronogaster sclerostoma sp. n. from banana soil near Karachi. Pakistan and C. neoparva sp. n. from soil around roots of Patisola sp. in Korup National Park, Cameroon are described and illustrated. C sclerostoma is characterised by large-sized (1.0-1.1 mm) body having crystalloids, expanded sclerotized cheilostom and long conoid tail with a single terminal spine. C neoparva sp. n. has 0.44-0.49 mm long body, cephalic setae indistinct, 3-4 urn long. vulva at 44.1-46.4 percent of body length and a filiform, 129-158 µm long tail. It resembles C. parva in most morphomelric details but can be distinguished from it in the absence of glandular bodies, smaller "V and 'c' values and a longer tail devoid of a mucro. Males were not found for both new species

Development of gonads in plant and soil nematodes - a review

The article describes the comparative gonad development among different nematode groups. The monoprodelphic gonad of female develops from a single primordium which is oriented parallel to the longitudinal axis. The development starts with proliferation of somatic nuclei posteriad while the germinal nuclei remain at the anterior end of primordium. In the didelphic secerncntea the gonad develops from a single primordium which may be longitudinally Oriented in tylenchs or obliquely oriented in some rhabditids and diplogasterids. In didelphic Adenophorea the gonad develops either from a single longitudinally oriented primordium (e.g dorylaims) or two primor-dia oblique in position with each other (e.g. mononchs). In Secernentean males the monorchic gonad develops as a result of anterior proliferation of somatic nuclei. The germinal nuclei thus remain at the posterior end. In diorchic condition which is exclusively found in Adenophorea the primordium elongates both in anterior and posterior direction to give rise to two opposed testes joined with a common vas deferens. The ventral hypodermal chord nuclei play an important role in gonad development. In females they form a part of vagina while in males they form the supplements. The spicules develop from the dorso-latcral aggregates of cells known as spicular primordia

Parkellus park us gen. n., sp. n. and Miconchus koreanus sp. n. (Mononchida), two new predaceous nematodes from Korea

A new genus of Mononchidae. Parkellus. with type species, P. parkus sp. n., from Korea is proposed and described. Its dorsal tooth is quite posteriorly located in the buccal cavity and this helps in differentiating the new genus from Coomansus Jairajpuri, 1977 which has its dorsal tooth situated anterior to middle of dorsal vertical wall. -P. parkus sp. n. is 2.07-2.50 mm long, buccal cavity 55-62×28-32 µm. cardia without tubercles, female gonads amphidelphic, spicules 82-92 µm long, gubernaculum 30-35 µm. veniromedian supplements 21-25 and tails 85-95 µm or 1.5 to 2.0 anal body-widths long. Miconchus koreanus sp. n. is unique in the genus Miconchus Andrassy 1958, because of its mono-prodelphic gonad without any trace of posterior sexual branch. Body 1.32-1.68 mm. long, buccal cavity 38-45x26-28 µm. cardia tuberculate and tails 117-142 µm or 3.5-4.0 anal body-widths long. The new species, M. koreanus sp. n. comes close to M. digiturus (Cobb, 1893) Andrassy, 1958 and M. tridonlus Buangsuwon & Jensen. 1966 but has no posterior rudimentary sexual branch or uterine sac

Description of two new species of Plectinae (Nematoda: Araeolaimida) from India

Two new plectid species from India are described and illustrated. Plectus glandulatus sp. n. has 917-1307 µm long body. strongly annulated cuticle; conspicuously large hypodcrmal glands: ovoid amphidial apertures; offset lip region; separate, globular, lips; thickly cuticularised. arcuate, cheilostomal walls: basal bulb with four to five paired denticulate ridges: a pair of pseudocoelomoeytes located posterior to the cardia and tail with a subtenninal spur and three pairs of caudal setae. Chiloplectus indicus sp. n. has 695-1041 pm long body: thick, transversely annulated, cuticle: three lateral incisures: markedly offset, narrow, lip region: lips with conical apices anil slightly raised papillae: inner margin of lips forming well cuticularised oral framework; prorhabdion as long as wide and comprising 20% of the stoma length; basal bulb with six pairs of denticulate ridges; paired pseudocoelomoeytes located posterior to the cardia. genital tract weakly developed and tail with one median spur and two pairs of caudal setae

Impact of the nematophagous fungus Pochonia chlamydosporia on nematode and microbial populations

The microbial and nematode populations associated with two plants (tomato and cabbage) inoculated with the nematophagous fungus, Pochonia chlamydosporia var. chlamydosporia or root knot nematode (Meloidogyne incognita), or both, were compared with those in unplanted controls. The dominant factor affecting culturable microbial populations was found to be the presence or absence of tomato plants. Generally microbial colony counts were lowest in unplanted soil, small increases were associated with cabbage and significantly greater numbers with tomato plants. Differences in microbial diversity (estimated from community profiles of carbon substrate utlisation, using Biolog) were observed between planted and unplanted soils, however, there were few differences between soils with either of the two plants. The presence of P. chlamydosporia was associated with a reduction in the numbers of plant parasitic nematodes (51%-78%) including the migratory ectoparasites, whereas free-living nematodes, culturable bacteria and bacterial populations assessed by Biolog were unaffected by the application of fungus

Description of Metarhabditis andrassyana gen sp. n. (nematoda: Rhabditidae) from India

Metarhabditis andrassyana gen. n., sp. n. from cow dung in India is described and illustrated. The new genus is characterised by medium- to large-sized body; slightly setoff lip region; six lips forming three doublets; rhabditoid stoma with cluster of knobbed setose denticles on metastegostomal swellings; uniformly cylindrical pharyngeal corpus; well developed didelphic gonad with proximally dilated oviducts; ovoid, setoff spcrmathecae; vulva with epiptygma and vulval flaps; rectum with rectal glands; sexual dimorphism in tail with females having long filiform and males with shorter tails: stout spicules with dorsal arm; a pseudopeloderan bursa: eight bursal papillae and copulatory muscle bands. The new genus resembles Rhabditella (Cobb. 1929) Chitwood. 1933 in the structure of spicules (with dorsal arms) but differs in having larger and greater number of metastomal denticles, a remarkably weak pharyngeal corpus, lesser number of genital papillae, a well developed bursa and presence of copulatory muscle bands

Coelomocytes: Biology and Possible Immune Functions in Invertebrates with Special Remarks on Nematodes

All metazoans are exposed to a wide range of microbes and have evolved complex immune defenses used to repel infectious agents. Coelomocytes play a key role in the defense reactions of most invertebrates. They are involved in important immune functions, such as phagocytosis, encapsulation, graft rejection, and inflammation, as well as the synthesis and secretion of several humoral factors especially in annelids and echinoderms. Coelomocytes in nematodes are variable in shapes from round, ovoid, cuboidal, and spindle-shaped to stellate or branched cells that are found usually at fixed positions in the pseudocoelom. Their number usually varies from 2 to 6. The model nematode, C. elegans lacks an adaptive immune system and the coelomocytes are capable of endocytosis, but their involvement in phagocytosis of bacteria seems unlikely. The aim of this review is to evaluate current knowledge on coelomocytes of invertebrates with special reference to nematodes. The morphology and structure of these coelomocytes are discussed along with their origin. Their relative positions and diversity in different nematode groups have also been discussed and illustrated