Thysanura is the now deprecated name of what was, for over a century, recognised as an order in the class Insecta. The two constituent groups within the former order, the Archaeognatha and the Zygentoma, share several characteristics, such as of having three long caudal filaments, the lateral ones being the cerci, while the one between (telson) is a medial cerciform appendage, specifically an epiproct. They are also both wingless, and have bodies covered with fine scales, rather like the scales of the practically unrelated Lepidoptera. In the late 20th century, it was recognized that the two suborders were not sister taxa, therefore Thysanura was paraphyletic, and the two suborders were each raised to the status of an independent monophyletic order, with Archaeognatha sister taxon to the Dicondylia, including the Zygentoma.
The name Apterygota is sometimes applied to a former subclass of small, agile insects, distinguished from other insects by their lack of wings in the present and in their evolutionary history; notable examples are the silverfish, the firebrat, and the jumping bristletails. Their first known occurrence in the fossil record is during the Devonian period, 417–354 million years ago. The group Apterygota is not a clade; it is paraphyletic, and not recognized in modern classification schemes. As defined, the group contains two separate clades of wingless insects: Archaeognatha comprises jumping bristletails, while Zygentoma comprises silverfish and firebrats. The Zygentoma are in the clade Dicondylia with winged insects, a clade that includes all other insects, while Archaeognatha is sister to this lineage.
The Archaeognatha are an order of apterygotes, known by various common names such as jumping bristletails. Among extant insect taxa they are some of the most evolutionarily primitive; they appeared in the Middle Devonian period at about the same time as the arachnids. Specimens that closely resemble extant species have been found as both body and trace fossils in strata from the remainder of the Paleozoic Era and more recent periods. For historical reasons an alternative name for the order is Microcoryphia.
Zygentoma are an order in the class Insecta, and consist of about 550 known species. The Zygentoma include the so-called silverfish or fishmoths, and the firebrats. A conspicuous feature of the order are the three long caudal filaments. The two lateral filaments are cerci, and the medial one is an epiproct or appendix dorsalis. In this they resemble the Archaeognatha, although the cerci of Zygentoma, unlike in the latter order, are nearly as long as the epiproct.
Coreamachilis is a genus of jumping bristletails in the family Machilidae. There is at least one described species in Coreamachilis, C. coreanus.
Corethromachilis is a genus of jumping bristletails in the family Machilidae.
Janetschekilis is a genus of jumping bristletails in the family Machilidae.
Leptomachilis is a genus of jumping bristletails in the family Machilidae. There is one described species in Leptomachilis, L. californica.
Mendeschilis is a genus of jumping bristletails in the family Machilidae. There is at least one described species in Mendeschilis, M. escorcai.
Neomachilis is a genus of jumping bristletails in the family Machilidae. There is one described species in Neomachilis, N. halophila.
Metagraphitarsus is a genus of jumping bristletails in the family Machilidae.
Meximachilis is a genus of jumping bristletails in the family Machilidae. There are at least three described species in Meximachilis.
Paetrobius is a genus of jumping bristletails in the family Machilidae.
Parapetrobius is a genus of jumping bristletails in the family Machilidae. Currently, there is one described species, Parapetrobius azoricus, which has only been found on Pico Island and the Formigas Islets in the archipelago of the Azores
Parateutonia is a genus of jumping bristletails in the family Machilidae.
Pseudocatamachilis is a genus of jumping bristletails in the family Machilidae. There is at least one described species in Pseudocatamachilis, P. torquata.
Pseudomachilanus is a genus of jumping bristletails in the family Machilidae.
Silvestrichiloides is a genus of jumping bristletails in the family Machilidae.
Protrinemuroides is a genus of silverfish in the family Protrinemuridae. It only comprises the type species Protrinemuroides celebicusMendes, 2002, found on the Indonesian island of Sulawesi.
Lepidotrix is an extinct genus of wingless insect belonging to Zygentoma in the family Lepidotrichidae. There is one described species in Lepidotrix, L. piliferum/pillifera. It is known from specimens found in Eocene aged Baltic amber and Rovno amber. The genus lacks occelli. Its relationship with the extant genus Tricholepidion, which has historically been placed in the same family, is disputed, with some studies finding the two taxa to not be closely related, with Tricholepidion being placed in its own family instead. While often spelled Lepidothrix in historic literature, this is homonymous with a genus of birds, and Lepidotrix was the spelling used in the original publication.
