LONCHOPTEROIDEA, Curtis, 1839

Grimaldi, David A., 2018, Basal Cyclorrhapha In Amber From The Cretaceous And Tertiary (Insecta: Diptera), And Their Relationships: Brachycera In Cretaceous Amber Part Ix David A. Grimaldi, Bulletin of the American Museum of Natural History 2018 (423), pp. 1-97 : 1-97

SUPERFAMILY LONCHOPTEROIDEA

This is a group comprised of the monogeneric Recent family Lonchopteridae ( Lonchoptera Meigen ) plus four stem-group Cretaceous fossils in three extinct genera, discussed below and in Grimaldi and Cumming (1999): Lonchopterites Grimaldi and Cumming , Lonchopteromorpha Grimaldi and Cumming , and Alonchoptera , n. gen. The approximately 55 described species of Lonchoptera are gracile, yellowish to grayish, pollinose flies of moderate size. Interestingly, there are no definitive Tertiary fossils of Lonchopteridae ( Evenhuis, 1994) , even from the prolific Baltic amber and Florissant and Green River shale deposits, which would be immediately recognizable based on wings. The only fossils are four species from the mid-Cretaceous Burmese amber and Early Cretaceous Lebanese amber, all of which are minute flies slightly longer than one millimeter, substantially smaller than living species. A suite of features, many of them concerning the wing, indicates the close relationship of these Cretaceous genera to Lonchopteridae (fig. 24, table 1), such as:

(1) long setae on head, including a pair of large interfrontal reclinate setae positioned very close to anterior margin of frons;

(2) base of arista generally slightly dorsal to the apex of the basal flagellomere;

(3) pair of large vibrissae present, although none of the fossils have the row of large, protruding setae on the oral margin;

(4) males are dichoptic, although this is known for the fossils with certainty only in Lonchopterites burmensis , n. sp. (the sex is uncertain for Lonchopteromorpha asetocella Grimaldi and Cumming );

(9) vein C has long spinules, although most of the fossils lack the row of lateral setae on vein C.

Some of these apomorphic features, and those in table 1, are shared with Phoridae and/or Opetiidae and Platypezidae , such as the interfrontals, dichoptic male eyes and several of the vein features. Whether these characters are synapomorphic for these families will require a comprehensive phylogenetic study (see below). The fossil lonchopteroids lack some of the synapomorphies of Lonchoptera (e.g., setulose R and M veins; pointed wing tip), thus indicating their stem-group nature. Rather than redefining the concept of Lonchoptera or Lonchopteridae as more inclusive and less specific, I feel it is best to leave the three fossil genera as incertae sedis within a superfamily Lonchopteroidea (fig. 24).

The family Lonchopteridae has traditionally been accorded an isolated but uncertain position at or near the base of the Cyclorrhapha, as either near the Phoroidea ( McAlpine, 1989; Woodley et al., 2009), or closer to the base of the entire Cyclorrhapha ( Griffiths, 1972; Hennig, 1976; Wiegmann et al., 2010). Early Cretaceous lonchopteroids indicate that the lineage clearly diverged early in the history of Cyclorrhapha.