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. Around 2003, there was a view in favour of a single subfamily Issinae, but the current consensus is placement in four. 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

[Hysteropterinae]

Authority: Melichar, 1906; there are currently 59 genera including:Agalmatium Emeljanov, 1971Falcidius Stål, 1866Hysteropterum Amyot & Audinet-Serville, 1843 - type genus

Issinae

The monotypic subfamily contains the sole tribe Issini Spinola, 1839 and has a widespread distribution in Europe, the Middle East and temperate Asia. There are currently ten genera:Carimeta Gnezdilov, 2020Cophteroma Gnezdilov, 2020Cyclometa Gnezdilov, 2020

Thioniinae

Authority: Melichar, 1906
There are currently 3 tribes and 16 genera:

Issidae ''[incertae sedis]''

Twenty genera are currently placed here:Abolloptera Gnezdilov & O'Brien, 2006Argepara Gnezdilov & O'Brien, 2008Aztecus Gnezdilov & O'Brien, 2008Balduza Gnezdilov & O'Brien, 2006Bumaya Gnezdilov & O'Brien, 2008Carydiopterum Gnezdilov, 2017Delongana Caldwell, 1945Exortus Gnezdilov, 2004Gilda Walker, 1870Incasa Gnezdilov & O'Brien, 2008Kathleenum Gnezdilov, 2004Paralixes Caldwell, 1945Sarnus Stål, 1866Stilbometopius Gnezdilov & O'Brien, 2006Traxanellus Caldwell, 1945Traxus Metcalf, 1923Tylanira Ball, 1936Ulixes Stål, 1861Ulixoides Haupt, 1918
Uphodato Szwedo 2019, Krundia Szwedo 2019 and Breukoscelis Szwedo 2019 from the Bembridge Marls, England dating Eocene were considered members of this family upon description, however, other authors have found assignation to Issidae dubious.