Hirmoneura Meigen, 1820: 132

Grimaldi, David A., 2016, Diverse Orthorrhaphan Flies (Insecta: Diptera: Brachycera) In Amber From The Cretaceous Of Myanmar: Brachycera In Cretaceous Amber, Part Vii David A. Grimaldi, Bulletin of the American Museum of Natural History 2016 (408), pp. 1-132 : 50

Hirmoneura Meigen, 1820: 132 ; Bernardi, 1973

(synonyms and major subsequent citations).

DIAGNOSIS (adapted and modified from Bernardi, 1973): Head broad, hemispherical; proboscis small, barely visible past oral margin; basal flagellomere drop shaped, with three slender, apical flagellar articles forming stylus, apical article longest and fine; venation with few or generally no apical radial and medial cells; cell cup absent; hypandrium (male) highly reduced or lost; female cerci long, tapered, apically pointed.

TYPE SPECIES: Hirmoneura obscura (Wiedemann) , Recent.

COMMENTS: Hirmoneura are one of the three largest genera in the Nemestrinidae after Trichophthalma Westwood and Nemestrinus Latreille. It contains approximately 50 described living species distributed nearly equally between Old and New worlds (Bernardi, 1973). The venation of this genus and the two largest ones (above) are very similar and generalized, with the least amount of vein coalescence among nemestrinid genera; these genera also share similarities in antennal structure and a distinctive modification of the ocelli, where the anterior ocellus is separated considerably anterior to the posterior ones and on a separate mound. These three genera are probably closely related, though phylogenetic work is needed to test this. Interestingly, in the one Burmese amber specimen in which the dorsum of the head is visible, the ocelli are unmodified, no doubt plesiomorphically. The female cerci of Hirmoneura caudoprima , however, are extended into a long, tapered, pointed oviscapt, like many of the modern species of the genus. All three of the Burmese amber species also lack the dense, long pilosity of modern species. Monophyly of modern Hirmoneura is supported by a hypandrium in the male that is small or usually lost, unknown for the fossil taxa. There are three species of Hirmoneura based on compression fossils from the Early Cretaceous of Spain and Siberia (Mostovski and Delclòs, 2000); these have a closed cell cup. The genus is also recorded from the Cenozoic ( Wedmann, 2007). Otherwise, the venation of Cretaceous Hirmoneura is remarkably similar to modern species, but this may just be a plesiomorphic resemblance, as the ocelli of the amber Hirmoneura suggests these three species to be stem groups. The recent venation terminology is used here rather than that in Bernardi’s (1973) work, with differences as follows: R 3+4 (vs. R 4 in Bernardi), M 3 +CuA 1 (vs. M 3 +M 4), CuA 2 (vs. Cu 1).