PTERALIA OF THE PALEOZOIC INSECT ORDERS 
PALAEODICTYOPTERA, MEGASECOPTERA AND 
DIAPHANOPTERODEA ( PALEOPTERA) * 
By Jarmila Kukalova-Peck 
Department of Geology, Carleton University 
Ottawa, Ontario, Canada 
For an understanding of insect evolution the structure of the wing 
base is of major significance. However, the fossil record of pteralia 
in extinct orders is extremely scanty. This paper is concerned with 
the wing bases of certain Paleozoic Paleoptera, namely, Palaeodictyop- 
tera, Megasecoptera and Diaphanopterodea from the Upper Carboni- 
ferous (Namurian) of Czechoslovakia, the Upper Carboniferous 
(Stephanian) of France, and the Lower Permian of Czechoslovakia 
and Kansas. Independently of the Neoptera, the Diaphanopterodea 
acquired the ability to flex the wings backwards over the abdomen. 
In this respect, the order is of special interest, and an attempt is 
made here to compare the pteralia of the Diaphanopterodea with 
those of extant Ephemeroptera. 
Our present knowledge of the wing base in Paleozoic Paleoptera 
is restricted to the axillary plate of several palaeodictyopteran adults 
(Kukalova, i960, 1969-70), and palaeodictyopteran nymphs (Woot- 
ton, 1972; Sharov, 1971) [See figures 1, 2 and 4]. Recently, the 
wing base has been described in the Diaphanopterodea, Family El- 
moidae (Kukalova-Peck, 1974) (fig. 8). In the present paper, the 
axillary plates in Martynoviidae and Asthenohymenidae of the Order 
Diaphanopterodea are included, and for the first time the axillary 
sclerites in Megasecoptera are described. 
The interpretation and terminology of the pteralia in extinct Pale- 
optera are necessarily dependent upon the detailed functional mor- 
phology of extant Ephemeroptera and Odonata. At the same time, 
the wing base structures found in extinct orders provide an evolu- 
tionary view and might be helpful in unraveling the enigmatic archi- 
*This research has been aided in part by a Publication Grant from 
Carleton University and in part by a National Science Foundation Grant, 
GB 39720, F. M. Carpenter, Principal Investigator, Harvard University. 
I am deeply indebted to Dr. Carpenter for his assistance in finding speci- 
mens and for placing them at my disposal at the Museum of Comparative 
Zoology. I also wish to express my sincere gratitude to Dr. R. J. Wootton 
(University of Exeter, England) and Dr. P. A. Adams (California State 
University at Fullerton) for their valuable critical comments. 
Manuscript received by the editor December 15, 1974. 
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