Diastolaimus grossus




Rev 11/22/2022

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Morphology and Anatomy Life Cycle
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Diastolaimus grossus  (Truskova & Eroshenko, 1977) Andrassy, 1984


Diastolaimus grossuswas originally described as Fescia grossa by Truskova & Eroshenko (1977) from Chuguyevsky district, Primorsky Krai (Far Eastern Siberia, Russia) . Genus Fescia was  synonymized with Diastolaimus by Andrassy (1984) and Fescia grossus became Diastolaimus grossus (Truskova & Eroshenko, 1977) Andrassy, 1984.

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Morphology and Anatomy:


  • Didelphic-amphidelphic, both ovaries reflexed near to oviduct junction, very long, surpassing the level of the vulva.
  •  Oviduct narrow and short with distinct narrowing spermatheca containing big spherical sperms.
  • Vagina straight, occupying one-third of body diameter. Vulva a transverse slit, with distinctly protruded lips that forms a vulval cone;
  • Tail conical, slightly ventrad curved, tapering very gradually and ending in a filiform forked terminus
  • Phasmids  at 43-44% of tail length from anus.

Ref: Cermak et al., 2022


  • Monorchic, testis reflexed ventrad, on right-hand side of intestine. Spermatocytes first in two rows, then in only one row.
  • Spicules paired and symmetrical, 5.7-6.0 times longer than wide, curved ventrad with rounded manubrium, cylindrical calamus, ventrad curved lamina with reduced dorsal hump and a well-developed ventral velum.
  • Gubernaculum long, with thin manubrium and corpus with low central cuneus and well-developed triangular lateral crura.
  •  Fourteen pairs of genital papillae; eight subventral precloacal pairs and six postcloacal pairs.
  •  Tail conoid and tapering gradually and curved ventrad, ending in a short terminally forked filiform part.
  • Phasmids located in anterior half of tail, at 48% from anus.

Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:


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Originally described in 1977 from tree bark on branches of Abies sp. in Chuguyevsky district, Primorsky Krai (Far Eastern Siberia, Russia) . More recent collections (Cermak et al., 2022) Swere collected from bark from the bark from Namest na Hane,  Czech Republic (Salix sp.) and from Banja Luka, Bosnia and Herzegovina (Pinus nigra ).


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Presumed bacterial feeders but maybe also feeding on other microbes and fungal spores.

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Biology and Ecology:

All the members of the subfamily Chambersiellinae are considered epiphytic nematodes that live on the bark of various tree species and can survive rapid and long dehydration (Cermak et al., 2022)


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Life Cycle:


Ecophysiological Parameters:

For Ecophysiological Parameters for this species, click If species level data are not available, click for genus level parameters


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Ecosystem Functions and Services:



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Andrassy, I. 1984. Klasse Nematoda. (Ordnungen Monhysterida, Desmoscolecida, Araeolaimida, Chromadorida, Rhabditida). Akademie Verlag, Berlin, 509 pp.

Cermak, V. Njezic, B., Foit, J., Kulich, P., Orsagova, H., Ruiz-Cuenca, A.N., Shokoohi, E., Abolafia, J. 2022. Redescription of Diastolaimus grossus (Truskova & Eroshenko, 1977) Andr�ssy, 1984 (Rhabditida, Chambersiellidae) from Europe and comments on its phylogenetic position. Journal of Helminthology 96, e31, 1�14. https://doi.org/ 10.1017/S0022149X22000141

Truskova, G.M. & Eroshenko, A. 1977. Nematofaune vegetativnykh organov travjanistykh i drevesnykh rastenij elnikov primorja. Trudy Biologo-Pochvennogo Instituta 47:35-49.



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Copyright  1999 by Howard Ferris.
Revised: November 22, 2022 .