Issidae

Issidae is a family of planthoppers described by Spinola in 1839, belonging to the order Hemiptera, suborder Auchenorrhyncha superfamily Fulgoroidea.
Distribution
Species of this family are present throughout the Northern Hemisphere.
Description
Issidae are small insects generally with a stocky body, as the wings mainly develop in width. Basic body coloration is not striking, usually shows brownish colors. The head has two ocelli. The forewings have strong pronounced ribs. They wrap the abdomen when the insect is at rest. The family originally included approximately 1000 species with 215 genera, but the systematics of Issidae remains uncertain, with many of the subfamilies having been recently removed to separate families, including Caliscelidae. Nogodinidae, and Tropiduchidae.
In 2013, scientists described a biologically unique set of mechanical gears in an Issus nymph, though identical structures are known in most planthoppers, and were known for decades before the function of the gears was discovered
Taxonomy
The family Issidae was once large and included many groups which are now treated in other families or as families themselves. These groups include the Caliscelidae, Nogodinidae, and Tropiduchidae (e.g., subfamilies Tonginae and Trienopinae). Around 2003, there was a view in favour of a single subfamily Issinae, but the current consensus is placement in four (as below). The Catalogue of Life lists genera in five tribes Issini, Parahiraciini, Hemisphaeriini and Thioniini. The tribe Colpopterini have now been placed in family Nogodinidae Melichar, 1898 having been raised to a subfamily. The oldest fossil of the group is Cubicostissus of the Paleocene Menat Formation of France, belonging to the tribe Hysteropterini, molecular clock calibrations suggest a diversification during the Upper Cretaceous.
Subfamilies, Tribes and selected Genera
Fulgoromorpha Lists On the Web lists four subfamilies:
Hemisphaeriinae
Authority: Melichar, 1906
Hemisphaeriini Melichar, 1906
Gergithus
Hemisphaerius
Kodaianellini Wang, Zhang & Bourgoin, 2016
Parahiraciini Cheng & Yang, 1991
†Bolbossus Gnezdilov & Bourgoin, 2016 Baltic amber, Eocene (Priabonian)
Sarimini Wang, Zhang & Bourgoin, 2016
Hemisphaeriinae incertae sedis
Hysteropterinae
Authority: Melichar, 1906; there are currently 61 genera including:
Agalmatium Emeljanov, 1971
Falcidius Stål, 1866
Hysteropterum Amyot & Audinet-Serville, 1843 - type genus
†Cubicostissus Bourgoin & Nel, 2020 Menat Formation, France, Paleocene (Selandian)
Issinae
The monotypic subfamily contains tribe Issini Spinola, 1839 and has a widespread distribution in Europe, the Middle East and temperate Asia. There are currently four genera:
†Issites Haupt, 1956 Germany, Eocene (Lutetian)
Issus Brullé, 1832 – type genus
Latissus Dlabola, 1974
Sinonissus Wang, Shi & Bourgoin, 2018
Thioniinae
Authority: Melichar, 1906
There are currently 3 tribes and 16 genera:
Cordelini Gnezdilov, 2019 (1 genus)
Cordela Gnezdilov, 2019
Guianaphrynini Gnezdilov, 2018 (1 genus)
Guianaphryna Gnezdilov, 2018
Thioniini Melichar, 1906 (14 genera)
Amnisa Stal, 1862
Diceroptera Gnezdilov, 2011
Dracela Signoret, 1861
Heremon Kirkaldy, 1903
Oronoquina Gnezdilov, 2018 (1 genus)
Oronoqua Fennah, 1947
Paranipeus Melichar, 1906
Proteinissus Fowler, 1904
Thioniamorpha Metcalf, 1938
Thioniella Metcalf, 1938
Thioniina Melichar, 1906
Aplos Gnezdilov, 2018
Cheiloceps Uhler, 1895
Fowlerium Gnezdilov, 2018
Thionia Stal, 1859
Waoraniina Gnezdilov & Bartlett, 2018 (1 genus)
Waorania Gnezdilov & Bartlett, 2018
Issidae incertae sedis
Twenty genera are currently placed here:
Abolloptera Gnezdilov & O'Brien, 2006
Argepara Gnezdilov & O'Brien, 2008
Aztecus Gnezdilov & O'Brien, 2008
Balduza Gnezdilov & O'Brien, 2006
Bumaya Gnezdilov & O'Brien, 2008
Carydiopterum Gnezdilov, 2017
Delongana Caldwell, 1945
Exortus Gnezdilov, 2004
Gilda Walker, 1870
Incasa Gnezdilov & O'Brien, 2008
Kathleenum Gnezdilov, 2004
Paralixes Caldwell, 1945
Sarnus Stål, 1866
Stilbometopius Gnezdilov & O'Brien, 2006
Traxanellus Caldwell, 1945
Traxus Metcalf, 1923
Tylanira Ball, 1936
Ulixes Stål, 1861
Ulixoides Haupt, 1918
Uphodato Szwedo 2019, Krundia Szwedo 2019 and Breukoscelis Szwedo 2019 from the Bembridge Marls, England dating Eocene (Priabonian) were considered members of this family upon description, however, other authors have found assignation to Issidae dubious.
References
W. E. Holzinger, I. Kammerlander, H. Nickel: The Auchenorrhyncha of Central Europe - Die Zikaden Mitteleuropas. Volume 1: Fulgoromorpha, Cicadomorpha excl. Cicadellidae. - Brill, Leiden 2003
Stephen W. Wilson – Keys to the families of Fulgoromorpha with emphasis on planthoppers of potential importance in the Southern United States -Florida Entomologist 88(4) Fcla.edu
External links
Fauna Europaea
Biolib
Auchenorrhyncha families
Fulgoromorpha
Taxa named by Maximilian Spinola