Piesmatidae
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| Ash-grey leaf bugs | ||||||||||||||||||||||||
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| 3 genera, c. 40 species | ||||||||||||||||||||||||
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Zosmenidae Dorhn, 1859 |
Piesmatidae is a small family of true bugs, commonly called ash-grey leaf bugs. It contains a mere three living genera with about 40 described species altogether. The Piesmatidae are distributed mostly in the temperate Northern Hemisphere, with some occurring in Africa, Australia and South America. A common species found throughout the Americas is Piesma cinereum.[1]
Ash-grey leaf bugs are small insects, some 2-4 mm overall. The head, thorax and the firm part of the wings are extensively dimpled. This resembles the similar pattern of the Tingidae of the infraorder Cimicomorpha, and was initially taken to signify a close relationship. It is due to convergent evolution however.[1]
They feed on plant sap, mostly of Chenopodiaceae and Caryophyllaceae. Piesma linnavouri and Mcateella have been found on Acacia (Fabaceae). The host plants of Miespa remain unknown.[1]
[edit] Systematics
Three-quarters of the named species are in the type genus Piesma, from which the subgenera Afropiesma and Parapiesma are sometimes split off. The genus Thaicoris was for some time placed here, but is now recognized to be a member of the Thaumastocoridae.[1]
There are three fossil genera. Cretopiesma was found in mid-Cretaceous amber from Myanmar and lived about 100 mya (million years ago). Eopiesma from the earliest Eocene (about 55 mya) is still a very basal member of the family. Heissiana, found in Baltic amber from the Eocene might be a northern relative of Mcateella and Miespa but given its distribution it might more comfortably be considered closely related to the ancestor of Eopiesma.[1]
The closest relatives of the Piesmatidae remain rather insufficiently determined. After the ash-grey leaf bugs were recognized as Pentatomomorpha, they were most often placed in the Lygaeoidea based on cladistic analysis, with their relatives variously presumed to be the Berytidae, Colobathristidae and Malcidae, or the peculiar, beetle-like Psamminae, a subfamily of the Lygaeidae. For some time, the Psamminae were even included in the Piesmatidae.[1]
Alternatively, the ash-grey leaf bugs were considered Pentatomomorpha incertae sedis or placed in a monotypic superfamily Piesmatoidea. With the discovery of Cretopiesma, this view seems perhaps the most warranted one. The origin of the Pentatomomorpha cannot lie much before the Early Cretaceous, and from the same time as Cretopiesma the Aradoidea genus Archearadus is known which resembles the most ancient piesmatid very much. Therefore, the Piesmatidae are indeed best considered incertae sedis among the Pentatomomorpha, until a cladistic analysis including the Cretaceous fossils can clarify the relationship between Aradoidea and Lygaeoidea.[1]
[edit] Footnotes
[edit] References
- Grimaldi, David A. & Engel, Michael S. (2007): An Unusual, Primitive Piesmatidae (Insecta: Heteroptera) in Cretaceous Amber from Myanmar (Burma). American Museum Novitates 3611: 1-17. DOI:10.1206/0003-0082(2008)3611[1:AUPPIH]2.0.CO;2 PDF fulltext
