Heydenius is a collective group genus of fossil mermithid nematodes from the Tertiary period that cannot be placed in extant genera.
Species Scientific name Age Type locality Country Host Notes Heydenius antiquus (von Heyden, 1860) Taylor, 1935 Oligocene/Miocene Rhine lignite Hesthesis immortua von Heyden, 1862(Coleoptera, Cerambycidae) Originally named Mermis antiqua von Heyden, 1860. Heydenius arachnius Poinar, 2012 Miocene Dominican amber Araneae Heydenius araneus Poinar, 2000 Eocene Baltic amber () Araneae, Thomisidae Heydenius brownii Poinar, 2001 Eocene Baltic amber () Hemiptera, Achilidae Heydenius cecidomyae Poinar, 2011 Eocene Baltic amber () Diptera, Cecidomyiidae Heydenius dipterophilus Poinar, 2011 Miocene Dominican amber Diptera, Milichiidae Heydenius dominicus Poinar, 1984 Miocene Dominican amber Culex(Diptera, Culicidae) Heydenius formicinus Poinar, 2002 Eocene Baltic amber () Prenolepis henschei Mayr, 1868(Hymenoptera, Formicidae) Heydenius lamprophilus Poinar, 2011 Miocene Dominican amber Coleoptera, Lampyridae Heydenius matutinus (Menge, 1866) Taylor, 1935 Eocene Baltic amber () Diptera, Chironomidae Originally named Mermis matutina Menge, 1866. Heydenius myrmecophila Poinar, Lachaud, Castillo & Infante, 2006 Miocene Dominican amber Linepithema(Hymenoptera: Formicidae) Heydenius neotropicus Poinar, 2011 Miocene Dominican amber Diptera, Chironomidae Heydenius phasmatophilus Poinar, 2012 Eocene Baltic amber () Balticophasma(Phasmatodea: Phasmatidae) Heydenius podenasae Poinar, 2012 Eocene Baltic amber () Lepidoptera Heydenius psychodae Poinar, 2011 Miocene Dominican amber Diptera, Psychodidae Heydenius quadristriatus (Menge, 1872) Taylor, 1935 Eocene Baltic amber () Unknown Originally named Mermis quadristriata Menge, 1872. Heydenius saprophilus Poinar, 2011 Miocene Dominican amber Diptera, Anisopodidae Heydenius scatophilus Poinar, 2011 Miocene Dominican amber Diptera, Scatopsidae Heydenius sciarophilus Poinar, 2011 Eocene Baltic amber () Diptera, Sciaridae Heydenius simulphilus Poinar & Currie, 2019 Eocene Baltic amber () Diptera, Simuliidae Heydenius tabanae Poinar, 2011 Late Pliocene(Piacenzian) Willershausen clay pit Tabanus sudeticus Zeller, 1842(Diptera, Tabanidae) Heydenius trichorosus Poinar, 2012 Eocene Baltic amber () Triaenodes balticus Wichard & Barnard, 2005(Trichoptera, Leptoceridae)
See also Cretacimermis
References