I was handed a specimen of mydas flies (Mydidae) by my colleague Norm Woodley the other day that was collected by USNM lepidopterists in 1989 in the Amazon basin of south-eastern Peru, specifically in the Madre de Dios Region. It was tugged away in a drawer and had not been incorporated into the main collection.
The specimen seemed interesting as there are only four species of Mydidae known from Peru in the genera Messiasia Andretta, 1951, Plyomydas Wilcox and Papavero, 1971, and Stratiomydas Wilcox, Papavero and Pimentel, 1989 (see catalog of Peruvian species here). This specimen, however, is very different and belongs in the genus Gauromydas Wilcox, Papavero and Pimentel, 1989.
Gauromydas includes the largest known fly, i.e., Gauromydas heros (Perty, 1833), distributed in south-eastern Brazil (see distribution here). The entire genus is only found in north-eastern South America and north-eastern Argentina, southern Brazil, and Paraguay (see distribution here). To my knowledge, it is so far unknown from the western Amazon Basin so that this unique specimen is quite exciting. Nelson Papavero, in the most recent catalog of Neotropical Mydidae (Papavero 2009), also does not record this genus from this part of the Amazon Basin.
There are four valid species of Gauromydas known to date (see species catalog here). While the specimen is morphologically similar to Gauromydas heros and keys out to that species in the Wilcox et al. 1989 key (electronic version available here), I am hesitant to call it that species because it is so far away from other collecting localities of G. heros.
Full occurrence data soon to be available in the NMNH collections database - USNMENT01115313.
It's always surprising to see what specimens might come your way.
Torsten Dikow @TDikow #asiloidflies