Abai, MR

6th International Congress of DipterologyOne less acalyptrate family? The status ofEurychoromyiidaeGaimari, S. D.California State Collection of Arthropods, Plant Pest Diagnostic Center, CaliforniaDepartment of Food & Agriculture, Sacramento, California, U.S.A.The Neotropical genus Eurychoromyia Hendel was described for the singlespecies E. mallea Hendel, based on four specimens collected over 100years ago by Carl Schnuse in the lower elevation Andean foothills north ofLa Paz, Bolivia. When described, the species was considered an isolatedgroup, classified in its own family-group coordinate in rank with Hendel'ssubfamilies Lauxaniinae (=Lauxanioidea) and Sciomyzinae(=Sciomyzoidea). Hennig was first to align the family with Lauxanioidea(in the current sense), a placement followed by the few subsequent authorsdealing with this issue, but being specifically aligned, in turn, with each ofthe other lauxanioid families. Hennig and Griffiths based an affinity withChamaemyiidae on presence of four spermathecae (2+2), while alllauxaniids known at the time had three (2+1). J.F. McAlpine at firstsuggested placement near Lauxaniidae (or Ropalomeridae, an idea quicklydismissed), but 20 years later suggested Celyphidae. Characteristics usedto support Celyphidae + Eurychoromyiidae either represent clear trendstowards reduction that have evolved in parallel in several lauxanioidlineages (e.g., reduction of macrosetae), general conditions also found inmany lauxaniids (e.g., widened fronto-orbital plates, elongated scape), andmisinterpretations of character states (e.g., convex bulging face, reducedcostal setulae). Even the autapomorphies McAlpine listed forEurychoromyiidae relative to the lauxanioid ground plan are conditionsfound in some lauxaniids (e.g., reduction of gonopods and parameres, fourspermathecae). Griffiths suggested (from an illustration of Henning) thatanother autapomorphy was the fusion of the 7th tergite and sternite into aring – a condition now known in various lauxaniid genera. The currentstudy provides evidence for reducing Eurychoromyiidae to a subfamilywithin Lauxaniidae, demonstrating the close relationship ofEurychoromyia with three unequivocal Neotropical lauxaniid genera80