Rev: 01/20/2026
Type species of the genus; Deladenus durus (Cobb, 1922) Thorne, 1941
Synonym
Dotylaphus Andrassy, 1958
Thorne (1941) created the genus Deladenus to accommodate tylenchid nematodes without a valvular median esophageal bulb. It was differentiated from other genera by the location of the esophageal-intestinal junction immediately behind the nerve ring, a median esophageal chamber present or absent, absence of a post-uterine sac and V > 90% (Thorne, 1941). More recent studies indicate the presence of a post-uterine sac and more a more anterior location of the vulva in some species, for example D. megacondylus (Mwamula et al., 2025).
Ref: Jalainasab, et al., 2020
Often associated with bark of dead trees.
Food Sources and Feeding strategies for the genus Deladenus
Wood (1973) observed Deladenus durus feeding and reproducing on fungi in culture.
Several mycuphagus species have been described from the wood of dead trees (Mwamula et al., 2925).
Some species are parasites of insects
Some species are considered to have alternative life cycles, one as insect parasitic nematodes and another thought to feed on fungi, algae, or root hairs of higher plants. Examples: Fergusobia, Deladenus (Siddiqi, 2000; Yeates et al., 1993).
Deladenus nitobei is an internal parasite of a wood wasp, Sirex nitobei.. Parasitized wasps are collected as they emerge from dead logs. The parasitism results in a reduction in body size of females (Kanzaki et al., 2018).
Bedding, R. A. and Akhurst, R. J. 1978. Geographical distribution and host preferences of Deladenus species (Nematoda: Neotylenchidae) parasitic in siricid woodwasps and associated hymenopterous parasitoids. Nematologica 24:286-94.
Chitambar, J. J. 1991. On the genus Deladenus Thorne, 1941 (Nemata: Allantonematidae). Review of the mycetophagous stage. Revue de Nematologie 14:427-444
Cobb, N. A. 1922. Two tree-infesting nemas of the genus Tylenchus. Annales de Zoologia Aplicada 9:27-35.
Fenili, R.; Mendes, C. J.; Miquelluti, D. J.; Mariano-da-Silva, S.; Xavier, Y.; Ribas, H. S.; Furlan, G.. 2000. Deladenus siricidicola, Bedding (Neotylenchidae) parasitism evaluation in adult Sirex noctilio, Fabricius, 1793 (Hymenoptera: Siricidae). Revista Brasileira de Biologia 61: 683-687.
Jalainasab, P., Esmaelli, M., Ye, W., Heydari, R. 2020. Description of Deladenus gilanica n. sp. (Hexatylina: Neotylenchidae) isolated from wood of black pine in Northern Iran. J. Nematology 52: | DOI: 10.21307/jofnem-2020-065
Mwamula, A.O., Bae, C-h., Kim, Y.S., Lee, D.W. 2025. Description of Deladenus uljinensis n. sp., and additional DNA barcode data for Deladenus posteroporus (Nematoda: Neotylenchidae) from Korea. J. Nematology 57:
Kanzaki, N., S.E. Tanaka, M. Ito, K. Tanaka, B. Slippers and M. Tabata. 2018. Some additional bionomic characters of Deladenus nitobei. Nematology 20:597-599.
Siddiqi, M. R. 2000. Tylenchida: Parasites of plants and insects, 2nd ed. Wallingford: CABI Publishing.
Thorne, G. 1941. Some nematodes of the family Tylenchidae which do not possess a valvular median esophageal bulb. Great Basin Naturalist, 2:37-85.
Wood, F.H. 1973. Nematode feeding relationships: Feeding relationships of soil-dwelling nematodes. Soil Riol. Biochem. 5: 593-601.
Yeates, G.W., T. Bongers, R.G.M. de Goede, D.W.Freckman and S.S. Georgieva. 1993. Feeding habits in soil nematode families - an outline for ecologists. Journal of Nematology 25:315-331.