A TRIASSIC ODONATE FROM ARGENTINA 
By F. M. Carpenter 
Harvard University 
The fossil insect described in this paper was collected in 1958 in 
the precordilleran region of Mendoza in Argentina by the joint ex- 
pedition of the Museum of Comparative Zoology and the Museo 
Argentino de Ciencias Naturales of Buenos Aires. The specimen was 
turned over to me for study by a member of the expedition, Professor 
Bryan Patterson. 
The rock containing the insect is a nearly white shale, with definite 
bedding and numerous plant fragments. The insect consists of the 
distal part of a wing, very clearly preserved. About 6 cm. away 
from this wing there is another specimen, consisting of a small, distal 
fragment of a wing. The larger specimen is clearly odonate but cer- 
tain structural details eliminate it from all described families of the 
order; because of our lack of knowledge of the proximal part of the 
wing, including the arculus region, I am placing this species in In- 
certae Sedis , in preference to establishing a new family on so few de- 
tails. The smaller wing fragment can be interpreted best by compari- 
son with the larger specimen, as will be noted below. 
Order Odonata 
Family: Incertae Sedis 
Genus Triassothemisj new genus 
Pterostigma well formed, elongate; nodus incomplete, without a 
costal indentation at the junction of the subcosta; nodus remote from 
the base of the wing: about 6 postnodals between nodus and ptero- 
stigma. The genus appears to be related to the suborder Archizygop- 
tera, which has been found in the Triassic of Australia and Jurassic 
of Europe and Asia (Turkestan). 
Type species: Triassothemis mendozensis, new species 
Triassothemis mendozensis , n. sp. 
Text figure 1 A, plate 9. 
Wing: length (as preserved), 25 mm.; width, 8.5 mm. Ptero- 
stigma about four times as long as wide, distinctly pigmented; costal 
border along the pterostigma somewhat thickened. Nodus incipient; 
subcosta distinctly thickened as it meets the costa; a short cross-vein 
between the end of the subcosta and Ri, this cross-vein being almost 
aligned with the cross-vein below it (extending from Ri to R2). R3 
separating from R2 at a point not much distal of the nodus; R2 and 
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