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40 (2001) suggest that they are the sister group to the Grylloblattodea. In contrast, Boudreaux

(1979) and Kukalova-Peck (1991) included the order in the blattoid group, though according to Kristensen (1981) the presumed synapomorphies are weak. Grylloblattodea (rock crawlers) show an interesting mixture of orthopteran, phasmid, dermapteran, and dicty-opteran features, which led to an early suggestion that they are remnants of a primitive stock from which both orthopteroids and blattoids evolved. According to Storozhenko (1997), grylloblattid fossils are known from the Middle Carboniferous onward, and these insects were among the most abundant insects in the Permian. He believes that the group included the ancestors of Plecoptera, Embioptera and Dermaptera. As noted above, Kamp's analysis showed that considerable similarity exists between the grylloblattids and dermapterans, which supports the conclusion reached by Giles (1963) and Wheeler et al. (2001) that the two may be sister groups.

The fossil record of the Embioptera (web spinners) extends back to the Lower Permian, though even by this stage the wing venation was reduced and the asymmetric genitalia of males was evident. Web spinners share features with the Plecoptera, Dermaptera, and Zoraptera], though it is unclear whether these are primitive or derived. Wheeler et al. (2001) place them as the sister group to Plecoptera based on examination of two species. The phylogenetic position of the Zoraptera (zorapterans) is also uncertain. The order is not encountered in the fossil record until the Upper Eocene/Lower Miocene. As noted, zorapterans share features with the web spinners, earwigs, and stoneflies; however, the few Malpighian tubules, composite abdominal ganglia, and two-segmented tarsi are features that could align them with the hemipteroids. Wheeler et al.'s (2001) analysis suggests a sister-group relationship with the Dictyoptera + Isoptera.

Included in the blattoid group of orders are the Protelytroptera (Permian-Lower Cretaceous), Dictyoptera (Upper Carboniferous-Recent), and Isoptera (Lower Cretaceous-Recent). Protelytropterans were apparently an abundant group judging by the amount of fossil material discovered, though this may be somewhat artifactual because their highly sclerotized, elytralike fore wings were readily preserved. The latter are remarkably similar to the elytra of some early Coleoptera, and often it is only when other evidence is available (e.g., the hind wing) that the correct identification can be made (Wootton, 1981). The Protelytroptera appear to be an early branch off the line leading to the Dictyoptera, and in Kukalova-Peck's (1991) view were probably ancestral to the Dermaptera. The Dictyoptera (cockroaches and mantids) and Isoptera (termites) are clearly monophyletic, and some authors (e.g., Kristensen, 1981, 1991) see little point in giving each of these ordinal status. Cockroaches underwent a massive radiation in the Upper Carboniferous (often referred to as the Age of Cockroaches in view of the commonness of their remains) and the order remains extensive today. Female Paleozoic cockroaches had a long, well-developed ovipositor, and the evolution of the short, internal structure seen in modern forms apparently did not occur until the end of the Mesozoic. Reports of fossilized oothecae from the Upper Carboniferous are, according to Carpenter (1992), "not very convincing." Within the Dictyoptera two trends can be seen. The cockroaches became omnivorous, saprophagous, nocturnal, often secondarily wingless insects, whereas the mantids (not known as fossils until the Eocene) remained predaceous and diurnal. Although termites are known as fossils only from the Cretaceous onward, comparison of their structure and certain features of their biology with those of cockroaches (some of which are subsocial) indicates that they are derived from blattoidlike ancestors (Weesner, 1960). Indeed, certain venational features and the method of wing folding in the primitive termite Mastotermes resemble those of fossil rather than extant cockroaches.

The relationships of the recently erected order Mantophasmatodea remain unclear. 41

Though unquestionably orthopteroid, members of this order possess a blend of features that

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