<p><strong>First fossil record of the genus <em>Reissa</em> Evenhuis & Báez (Diptera: Mythicomyiidae: Mythicomyiinae) from the Eocene Green River Formation of North America, and discussion of biogeographical implications</strong></p>

Abstract

The genus Reissa Evenhuis & Báez in Greathead & Evenhuis (2001) was originally described based on a short series of extant specimens from the island of Tenerife in the Canary Islands. No further species of the genus have been discovered since. A related fossil genus (Riga Evenhuis) was described from Eocene Rovno amber (Evenhuis, 2013) and has some characters in common with the fossil specimen but differs in thoracic and antennal features. The new species described and illustrated here is represented by a single compression fossil of the new species Reissa kohlsi sp. nov. from the Parachute Creek member of the Green River Formation of Wyoming/Utah/Colorado, USA, the site of which dates from 51.2–48.7 my (Smith et al., 2008). It marks the first fossil record of the genus and its first record from the New World, and the first fossil record of the family Mythicomyiidae from North America. The family was previously known in the New World fossil record from the Miocene Dominican amber (cf. Evenhuis, 2013), including two representatives from the Mythicomyiinae (Mythicomyia dominicana Evenhuis, 2002 and Pieza dominicana Evenhuis, 2002).