Nemathelminthes Gegenbaur, 1859 see Phylum Nematoda Gegenbaur, 1859 Class Nematoda Gegenbaur, 1859 Subclass Secernentia (Von Linstow, 1905) Andrássy, 1976 Order Tylenchida G. Thorne, 1949 Suborder Tylenchina Chitwood, 1950 Family Heteroderidae Filipjev & Schuurmans Stekhoven, 1941