| Psocodea | |
|---|---|
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| An unidentified bark louse in the familyStenopsocidae | |
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| Humanbody louse | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| (unranked): | Paraneoptera |
| Order: | Psocodea Hennig, 1966 |
| Suborders[1] | |
Psocodea is ataxonomic group ofinsects comprising the bark lice, book lice andparasitic lice.[2] It was formerly considered asuperorder, but is now generally considered by entomologists as anorder.[1][3][4] Despite the greatly differing appearance of parasitic lice (Phthiraptera), they are believed to have evolved from within the former orderPsocoptera, which contained the bark lice and book lice, now found to beparaphyletic.[5][6]
Psocodea contains around 11,000 species, divided among three suborders and more than 70 families.[1][2][7] They range in size from 1–10 millimetres (0.04–0.4 in) in length.
The species known as booklice received their common name because they are commonly found amongst oldbooks—they feed upon the paste used inbinding. The barklice are found on trees, feeding on algae andlichen.
Psocodea has been recovered as amonophyletic group in recent studies. Their next closest relatives are traditionally recognized as the monophyletic groupingCondylognatha that containsHemiptera (true bugs) andThysanoptera (thrips), which all combined form the groupParaneoptera. However, this is somewhat unclear, as analysis has shown that Psocodea could instead be thesister taxon toHolometabola, which would render Paraneoptera asparaphyletic.[6]
Here is a simplecladogram showing the traditional relationships with a monophyletic Paraneoptera:[6]
| Neoptera |
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Here is an alternative cladogram showing Paraneoptera as paraphyletic, with Psocodea assister taxon toHolometabola:[6]
| Neoptera |
| Paraneoptera | ||||||||||||||||||||||||
Here is acladogram showing the relationships within Psocodea:[3]
| Psocodea | |
The order Psocodea (formerly 'Psocoptera') is divided into threeextantsuborders.
Trogiomorpha haveantennae with many segments (22–50 antennomeres) and always three-segmented tarsi.[8]
Trogiomorpha is the smallest suborder of the Psocopterasensu stricto (i.e., excludingPhthiraptera), with about 340 species in 7 families, ranging from the fossil familyArchaeatropidae with only a handful of species to the specioseLepidopsocidae (over 200 species).Trogiomorpha comprises infraorderAtropetae (extant familiesLepidopsocidae,Psoquillidae andTrogiidae, and fossil families Archaeatropidae andEmpheriidae) and infraorderPsocathropetae (familiesPsyllipsocidae andPrionoglarididae).
Troctomorpha have antennae with 15–17 segments and two-segmented tarsi.
Troctomorpha comprises the InfraorderAmphientometae (familiesAmphientomidae,Compsocidae,Electrentomidae,Musapsocidae,Protroctopsocidae andTroctopsocidae) and InfraorderNanopsocetae (familiesLiposcelididae,Pachytroctidae andSphaeropsocidae). Troctomorpha are now known to also contain the orderPhthiraptera (lice), and are therefore paraphyletic, as are Psocoptera as a whole.
Some Troctomorpha, such asLiposcelis (which are similar to lice in morphology), are often found in birds' nests, and it is possible that a similar behavior in the ancestors of lice is at the origin of the parasitism seen today.[8]
Psocomorpha are notable for having antennae with 13 segments. They have two- or three-segmented tarsi, this condition being constant (e.g., Psocidae) or variable (e.g., Pseudocaeciliidae) within families. Their wing venation is variable, the most common type being that found in the genusCaecilius (rounded, free areola postica, thickened, free pterostigma, r+s two-branched, m three-branched). Additional veins are found in some families and genera (Dicropsocus andGoja in Epipsocidae, many Calopsocidae, etc.)
Psocomorpha is the largest suborder of the Psocopterasensu stricto (i.e., excludingPhthiraptera), with about 3,600 species in 24 families, ranging from the species-poor Bryopsocidae (2 spp.) to the speciose Psocidae (about 900 spp).[8]Psocomorpha comprises InfraorderEpipsocetae (familiesCladiopsocidae,Dolabellopsocidae,Epipsocidae,Neurostigmatidae andPtiloneuridae), InfraorderCaeciliusetae (familiesAmphipsocidae,Asiopsocidae,Caeciliusidae,Dasydemellidae andStenopsocidae), InfraorderHomilopsocidea (familiesArchipsocidae,Bryopsocidae,Calopsocidae,Ectopsocidae,Elipsocidae,Lachesillidae,Mesopsocidae,Peripsocidae,Philotarsidae,Pseudocaeciliidae andTrichopsocidae) and InfraorderPsocetae (familiesHemipsocidae,Myopsocidae,Psilopsocidae andPsocidae).
