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Volume 2, Part 2 (1994)

Tchesunov, A.V.

Description of a marine free-living nematode Stephanolaimus graciosus sp. n. and erection of Setostephanolaimus gen. n. (Chromadoria: Leptolaimidae)

Stephanolaimus graciosus sp. n. is described from the benthos in the South Atlantic off Namibia coast. The new species differs from S. elegans Ditlevsen, 1918, the only other member of the genus Stephanolaimus s. str. by having shorter cervical setae, fewer tubular supplements (9 vs. 36-45) and the presence of postanal papilla vs. preanal seta. The genus Stephanolaimus Ditlevsen, 1918 is revised and the majority of its species (apart from the type species and one described herein) is separated into a new genus Setostephanolaimus gen. n. The new genus differs from Stephanolaimus s. str. by the configuration of 6+4 cephalic setae vs. 4, simple labial region without a labial disc, amphid shape. S. jayasreei Platt, 1983 is considered to be conspecific with, and consequently junior synonym of S. longispiculum Jayasree, 1981.

Key words: Leptolaimidae, marine nematodes, Stephanolaimus graciosus sp. n., Setostephanolaimus gen. n., taxonomy.

Yushin, V.V. and Malakhov, V.V.

Ultrastructure of the body cuticle of free-living marine nematodes

The ultrastructure was studied of the body cuticle of 21 species of free-living marine nematodes belonging to 15 families in the Enoplida, Chromadorida, Desmodorida, Monhysterida and Araeolaimida. Most species had cuticles with osmiophilic epicuticle, striated exocuticle in the cortical position, fibrous mesocuticle and basally positioned endocuticle. The mesocuticle in enoplids, chromadorids, monhysterids and araeolaimids usually is multilayered and frequently has cavities crossed by intra-cuticular radial columns. Strongly sclerotized cuticles of nematode species belonging to the family Chromadoridae are comprised of mesocuticular transversal rings. The cuticle of desmodorids has a more specialized ultrastructure which may be considered as being modified. Punctuations of the cuticle of free-living marine nematodes appear to have evolved independently between orders.

Key words: marine nematodes, cuticle, ultrastructure.

Evtushenko, L.I., Dorofeeva, L.V. , Dobrovolskaya, T.G. and Subbotin, S.A.

Coryneform bacteria from plant galls induced by nematodes of the subfamily Anguininae

New associations are reported of coryneform bacteria with the gall-forming nematodes, Anguina agropyri, Heteroanguina graminophila, Mesoanguina picridis and Subanguina radicicola. Bacteria isolated were identified as Aureobacterium spp., Curtobacterium spp. and Rathayibacter spp. in accordance with the properties of the strains and bacterial classification. Three strains obtained from stem galls of Elytrigia repens and leaf galls of Calamagrostis neglecta could not be assigned to known genera. The taxonomic position of these three strains has to be determined. Bacteria-nematode associations appear to be more wide-spread among anguinids then has been previously described.

Subbotin, S.A., Chizhov, V.N. and Zakharenkova, N.N.

Ultrastructure of the integument of parasitic females in entomogenous tylenchids. I. Two species of the genus Wachekitylenchus, Allantonema mirabile and Bradynema rigidum

The structure of integument of parasitic female Wachekitylenchus bemibidi,W . bovieni, Allantonema mirabile and Bradynema rigidum were studied using transmission electron microscopy and compared with that present in several related species. In all species the microvilli layer covered the surface of hypodermis. Three types of structures of nematode body wall having hypodermal microvilli were revealed. The first type, observed in B. rigidum, W. bovieni and also in Howardula husseyi, contains only a microvilli layer. In the second type the body wall is covered with cuticle-like and microvilli layers: W. bembidi and A. mirabile. The third type - 'spongy layer', have only been observed in Skarbilovinema laumondi. The adaptive significance of microvilli for parasitism and use of this character in the systematics of entomogenous nematodes are discussed.

Key words: ultrastructure, integument, hypodermis, Wachekitylenchus bembidi, W. bovieni, Allantonema mirabile, Bradynema rigidum, entomogenous nematodes.

Kulinich, O.A., Kruglic, I.A., Eroshenko, A.S. and Kolosova, N.V.

Occurrence and distribution of the nematode Bursaphelenchus mucronatus in the Russian Far East

During the summer of 1991 - 1993 the conifer forests of the Russian Far East area were surveyed to determine the presence of the pinewood nematode Bursaphelenchus xylophilus (Steiner & Buhrer, 1934) Nickle 1970. Wood samples from branches, logs, and tops of dead and dying pine (Pinus sylvestris L., P. koraiensis Sieb. & Zucc.), spruce (Picea koraiensis Nakai, P. ajanensis Fisch.), larch (Larix dahurica Turcz.) and fir (Abies nephrolepis Maxim.) were assayed. The results showed that B. xylophilus was not present in the area, but a closely related nematode B. mucronatus was widespread. Morphological features of B. mucronatus from Primorsky territory are illustrated, the nematode distribution is given. B. mucronatus was obtained only from wood of plantation-grown Scots (P. sylvestris) and Korean (P. koraiensis) pines. The maximum number of B. mucronatus was found 20,000 nematodes per gram of pine (P. koraiensis) fresh wood. Most of infected B. mucronatus pines died during one summer, suggesting that B. mucronatus caused their death.

Key words: Russia, Far East, pinewood nematode, Bursaphelenchus xylophilus, B. mucronatus, conifers, Pinus sylvestris, P. koraiensis.

Ryss, A.Yu. and Sturhan, D.

Studies on Pratylenchoides ivanovae Ryss, 1980 and P. magnicauda (Thorne, 1935)

The type material of Pratylenchoides ivanovae and populations from Germany and Russia (St. Petersburg region and Chukchi peninsula) was compared with P. magnicauda specimens from Spitsbergen and data from the literature. The synonymy P. ivanovae =P. magnicauda is established and males of P. magnicauda are described for the first time. The less developed stylet and oesophagus in males, presence of lateral flanges on the spicules and the dorsal curvature of the male tail are characters supporting the inclusion of the species in the genus Pratylenchoides rather than in Amplimerlinius.

Key words: Pratylenchoides ivanovae, P. magnicauda, morphology, distribution, Germany, Russia.