The Palaeodictyoptera is perhaps paraphyletic to all other palaeodictyopterid "orders," and, pending a study of their phylogeny, they should be segregated into natural groups. Many "ordinal" names already exist for paleodictyopterans (e.g., Eugereonoptera of Crampton, various names of Hand-lirsch), which may need to be resurrected. The order can be characterized by large paranotal lobes, many of which resemble small wings, a well-developed archedictyon in the wing, and typically a broader, roughly triangular hind wing. All of these are primitive traits and the Palaeodictyoptera lacked traits that were derived relative to other palaeodictyopterid lineages.

The wings of Palaeodictyoptera were frequently boldly patterned (e.g., Dunbaria fascipennis: Figure 6.19) and may have been used for communication between conspecifics or in disruptive, startle responses when attacked by predators. Palaeodictyopterans could be enormous, achieving wingspans of around 550 mm (22 inches) (e.g., Mazothairos) (Figures 6.20, 6.21)! Indeed, the order included some of the largest insects on record, second only to the giants of the Protodonata. A walk through a Late Carboniferous or Early

Permian forest would encounter many palaeodictyopterans, and one can imagine startling a perched spilapterid or Steno-dictya that was feeding on a plant cone or leaf, flashing its wings in response.

Specimens of Palaeodictyoptera (e.g., Delitzschala bitter-feldensis) are among the earliest records of pterygote insects, having been recovered from near the Mississippian-Pennsyl-vanian boundary in Germany and in North America (Nelson and Tidwell, 1987; Brauckmann et al., 1996). The order is recorded from most of the known Paleozoic deposits and from a diversity of genera and families.

+1 0

Post a comment