Palæos:		Arthropoda
INVERTEBRATES		Paleodictyopteroidea

Parent: Paleoptera

Niece: Ephemoptera

Child:  Paleodictyopterida

Child: Megasecoptera,  Permothemistida & Diaphanopterodea

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The Paleodictyopteroidea were a diverse order of mostly large, rather solidly built paleopterous insects, which were widespread in the Upper Carboniferous.  We treat them as a paraphyletic assemblage, but cover our backsides by reserving the use of "Paleodictyoptera" for some possible monophyletic group of these insects.  Thus comfortably talking out of both sides of our mouths, we proceed to a description.

The largest had wingspans 20 to 50 cm across.  The Palaeodictyopteroidea are usually regarded as the most primitive winged insects so far known to have existed.  The wings were subequal (i.e. fore and hind pairs similar), sometimes widened, occasionally triangular.  The most interesting thing about these insects is the presence of paranota (fore-wings) on the first thoracic segment.  These are quite large and sometimes with rudiments of venation.

Despite their ancient status, the Paleodictyopteroidea already displayed specializations in that most, if not all, had mouth-parts modified into a long, suctorial rostrum - that is, piercing-sucking mouthparts for feeding upon plant sap.  This was not, however, the same as the hemipteran rostrum, but rather represented an independent (an earlier) adaptation to feeding on spores, pollen, fruit, etc.

The paleodictyopteroid wing (left) is generally taken as the ancestral type from which the other types evolved.  There is a complete system of venation, typically with the concave components (Rs, MP, CuP) arising as posterior branches from the convex components, and with a fully developed cubito-anal field which was sometimes more or less expanded.  The cross-veins are numerous, and regular or irregular.

The antennae are setose (bristly), the legs slender, abdominal segments usually with prominent lateral lobes, with cerci (two "tails") that are usually rather short, and no caudal style.  Some species were more slender, with reduced lateral processes and long cerci.

Links

Phylogenetic Systematics of basal Pterygota and Stem-Group Odonates - Günter Bechly,

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