Evolution
The fossil record of the Dermaptera starts in the Late Triassic to Early Jurassic period about 208 million years ago in England and Australia, and comprises about 70 specimens in the extinct suborder Archidermaptera. Some of the traits believed by neontologists to belong to modern earwigs are not found in the earliest fossils, but adults had five-segmented tarsi (the final segment of the leg), well developed ovipositors, veined tegmina (forewings) and long segmented cerci; in fact the pincers would not have been curled or used as they are now. The theorized stem group of the Dermaptera are the Protelytroptera. These insects, which resemble modern Blattodea, or Cockroaches owing to shell-like forewings and the large, unequal anal fan, are known from the Permian of North America, Europe and Australia. There are no fossils from the Triassic when the morphological changes from Protelytroptera to Dermaptera took place. The most likely, and most closely resembling, related order of insects is Grylloblattaria, theorized by Giles in 1963. However, other arguments have been made by other authors linking them to Phasmida, Embioptera, Plecoptera, and Dictyoptera.
Archidermaptera is believed to be sister to the remaining earwig groups. This suborder has tarsi with five segments (unlike the three found in the other suborders) as well as unsegmented cerci like Hemimerina and Arixenina; however, no fossil Hemimerina and Arixenina are known. Species in Hemimerina were at one time in their own order, Diploglassata, Dermodermaptera, or Hemimerina. Like most other epizoic species, there is no fossil record, but they are probably no older than late Tertiary.
Some evidence of early evolutionary history is the structure of the antennal heart, a separate circulatory organ consisting of two ampullae, or vesicles, that are attached to the frontal cuticle to the bases of the antennae. These features have not been found in other insects. An independent organ exists for each antenna, consisting of an ampulla, attached to the frontal cuticle medial to the antenna base and forming a thin-walled sac with a valved ostium on its ventral side. They pump blood by elastic connective tissue, rather than muscle.
Molecular studies suggest that this order is the sister to Plecoptera or to Ephemeroptera.
Read more about this topic: Earwig
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