The firebrat (Thermobia domestica) is a small insect (typically 1–1.5 cm) in the order Zygentoma.
The firebrat (Thermobia domestica) is a small insect (typically 1–1.5 cm) in the order Zygentoma.
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 (jumping bristletails) and the Zygentoma (silverfish and firebrats), 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.
Although the group Thysanura is no longer recognized, the name still appears in some published material. Another name used to separate the two groups from winged insects is Apterygota.
Pterygota (/ˌtɛrəˈɡoʊtə/ terrə-GOH-tə Ancient Greek: πτερυγωτός, romanized: pterugōtós, lit. 'winged') is a subclass of insects that includes all winged insects and groups which lost them secondarily.
Pterygota group comprises 99.9% of all insects. The orders not included are the Archaeognatha (jumping bristletails) and the Zygentoma (silverfishes and firebrats), two primitively wingless insect orders. Unlike Archaeognatha and Zygentoma, the pterygotes do not have styli or vesicles on their abdomen (also absent in some zygentomans), and with the exception of the majority of mayflies, are also missing the median terminal filament which is present in the ancestrally wingless insects.
Zygentoma are an order in the class Insecta, and consist of about 550 known species. The Zygentoma include the silverfishes 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.
Until the late twentieth century the Zygentoma were regarded as a suborder of the Thysanura, until it was recognized that the order Thysanura was paraphyletic, thus raising the two suborders to the status of independent monophyletic orders, with Archaeognatha as sister group 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 nymphs (younger stages) go through little or even no metamorphosis, hence they resemble the adult specimens (ametabolism).Currently, no species are listed as being at conservation risk.