Rev 01/11/2021
Aphelenchoides megadorus was described by Allen (1941) from specimens collected in desert soil near Mosida, Utah. Allens original description of A. megadorus did not designate a holotype, was based on drawings of poorly preserved specimens and did not include photographs, Goodey (1960) considered that the relatively (for a member of the Aphelenchoididaei) massive stylet with large knobs, the tapering of the esophagus anterior to the metacorpus, and the lack of a mucro on the tail. were sufficiently different to establish a new genus, Megadorus, with type species Megadorus megadorus (Allen, 1941) Goodey, 1960. Andrassy (2007) determined that the genus name Megadorus was pre-emptively used in the Class Insecta and established the genus Robustodorus, with type species Robustodorus megadorus (Allen, 1941) Andrassy, 2007.
Based on analysis of near-full-length small subunit (SSU), internal transcribed spacer (ITS) and D2-D3 expansion segments of the large subunit (LSU) rRNA genes, Kanzaki et al (2018) transferred Aphelenchoides arachidis and A. subtenuis to the genus Robustodorus as R. arachidis and R. subtenuis.
Metacorpus large, rounded-ovoid. DEGO just anterior to the metacorpus valve. Two subventral glands ducts open immediately after the valve. Excretrory pore opening ventral, between the metacorpus and nerve ring.
Esophageal glands overlap the intestine dorsally.
Reproductive systems monodelphic-prodelphic with a postuterine branch 1.3 to 2.3 times vulval body diameter
Vulva a transverse, thick-lipped slit, no vulval flap.
Crustaformeria pear shaped, anterior to uterus and separated by a sphincter
Spermatheca oval, without sperm.
Tail, slightly curved ventrally,conically rounded, 2x abd in length, tip smoothh, no mucro,.
Specimens of the genus Robustodorus have since been reported from Idaho, Montana, and several areas of the former Soviet Union (Ryss et al., 2013).
Robustidorus megadorus specimens have been seen infected with Pasteuria sp. (Ryss et al, 2013).
Allen, M.W.(1941). Aphelenchoides megadorus, a new species of Tylenchoidea (Nematoda). Proceedings of the Helminthological Society of Washington 821-23.
Andrássy, I. 2007. Free-living Nematodes of Hungary (Nematoda Errantia) Vol. II. Hungarian Natural History Museum. Budapest. Hungary, 496 pp.
Kanzaki, N., E. Shokoohi, H Fourie, A Swart, L Muller, R.M. Giblin-Davis. 2018. On the morphology and phylogeny of Robustodorus Andr�ssy, 2007 and two �Aphelenchoides� species (Nematoda: Aphelenchoidinae). Nematology 20:601-615.
Ryss, A.Y., McClure, M.A., Nischwitz, C., Dhiman, C., and Subbotin, S.A. 2013. Redescription of Robustodorus megadorus with Molecular Characterization and Analysis of Its Phylogenetic Position within the Family Aphelenchoididae. J. Nematology 45:237-252.