Scydmaeninae are a subfamily of small beetles, commonly called ant-like stone beetles or scydmaenines. These beetles occur worldwide, and the subfamily includes some 4,500 species in about 80 genera. Established as a family, they were reduced in status to a subfamily of Staphylinidae in 2009 Grebennikov, V.V. and Newton, A.F. 2009. Good-bye Scydmaenidae: or why the ant-like stone beetles should become megadiverse Staphylinidae sensu latissimo (Coleoptera). European Journal of Entomology 106: 275-301.
Many scydmaenine species have a narrowing between head and thorax and thorax and abdomen, resulting in a passing resemblance to ants that inspires their common name. They are typically small beetles, with some very small species only half a millimeter in length. Scydmaenids typically live in leaf litter and rotting logs in forests, preferring moist habitats. A number of types are known to feed on oribatid mites, using "hole scraping" and "cutting" techniques to get through the mite's hard shells.
In addition to the two living subfamilies, the prehistoric subfamily Hapsomelinae, known only from fossils, has been placed here.
Taxonomy
Supertribes
Cephenniitae Reitter, 1882 † Hapsomelitae Poinar & Brown, 2004 Mastigitae Fleming, 1821 Scydmaenitae Leach, 1815
Selected genera Cephennium Elacatophora Schaufuss, 1884 (including Borneosabahia) Euconnus Thomson, 1859 Eutheia Horaeomorphus Schaufuss, 1889 Loeblites Franz, 1986 Microscydmus Saulcy & Croissandeau, 1893 Nevraphes Parastenichnaphes Franz, 1984 Penicillidmus Jałoszyński, 2014 Protoscydmus Franz, 1992 Scydmaenus Siamites Franz, 1989 Stenichnus Thomson, 1859 Synidcus Motschulsky, 1851
Extinct genera
Clade Cephenniitae Reitter 1882 Tribe Cephenniini Reitter 1882 †Praphennium Jałoszyński 2018 Burmese amber, Myanmar, Cenomanian Tribe Eutheiini Casey 1897 †Archeutheia Jałoszyński and Peris 2016 El Soplao amber (Spanish amber), Spain, Albian Clade Mastigitae Fleming 1821 Tribe Clidicini Casey 1897 †Palaeoleptochromus O'Keefe 1997 Canadian amber, Foremost Formation, Campanian Tribe Leptochromini Jałoszyński and Brunke 2018 †Euroleptochromus Jałoszyński 2012 Baltic amber, Eocene †Rovnoleptochromus Jałoszyński and Perkovsky 2016 Rovno amber, Ukraine, Eocene Clade Scydmaenitae Leach 1815 †Kachinus Chatzimanolis et al. 2010 Burmese amber, Myanmar, Cenomanian Tribe Scydmaenini Leach 1815 †Kuafu Yin et al. 2017 Burmese amber, Myanmar, Cenomanian Tribe Stenichnini Fauvel 1885 †Cenomaniola Jałoszyński and Yamamoto 2017 Burmese amber, Myanmar, Cenomanian †Glaesoconnus Jałoszyński and Perkovsky 2016 Rovno amber, Ukraine, Eocene †Hyperstenichnus Jałoszyński and Perrichot 2017 Vendée amber, France, Turonian †Nuegua Yin et al. 2018 Burmese amber, Myanmar, Cenomanian †Pangusyndicus Yin et al. 2018 Burmese amber, Myanmar, Cenomanian †Scydmobisetia Jałoszyński and Yamamoto 2016 Burmese amber, Myanmar, Cenomanian †Taimyraphes Jałoszyński and Perkovsky 2019 Taimyr amber, Russia, Santonian †Clade Hapsomelitae Poinar and Brown 2004 †Ektatotricha Chatzimanolis et al. 2010 Burmese amber, Myanmar, Cenomanian †Electroatopos Chatzimanolis et al. 2010 Burmese amber, Myanmar, Cenomanian †Hapsomela Poinar and Brown 2004 Burmese amber, Myanmar, Cenomanian Incertae sedis †Cryptodiodon Schaufuss 1890 Baltic amber, Eocene †Electroscydmaenus Schaufuss 1890 Baltic amber, Eocene †Hetereuthia Schaufuss 1890 Baltic amber, Eocene †Heuretus Schaufuss 1890 Baltic amber, Eocene †Microlynx Kohring and Schlüter 1989 Sicilian amber, Miocene †Palaeothia Schaufuss 1890 Baltic amber, Eocene †Pinitoides Motschulsky 1856 Baltic amber, Eocene †Scydmaenoides Motschulsky 1856 Baltic amber, Eocene †Semnodioceras Schaufuss 1890 Baltic amber, Eocene
References Notes
Sources Ross H. Arnett Jr. and Michael C. Thomas, American Beetles (CRC Press, 2001), vol. 1