NEMESTRINIDAE (Barraclough, 2006)

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 : 49

FAMILY NEMESTRINIDAE

The family of “tangled-vein” flies is distinctive and relict, with only 250 world species in 23 genera, but in some areas they are ecologically vital. The group has an extensive fossil record. These flies are immediately recognized by the diagonal vein, in which obliquely aligned through the wing are portions or the entireties of veins Rs, base of R 4+5, crossvein r-m, portions of M 1-3, and CuA 1. Nemestrinids have one cercomere, a pulvilliform empodium, two palpomeres, no tibial spurs, and primitively four flagellar articles (often reduced to one or two), the apical 1–3 articles formed into a slender stylate portion of the antenna. The proboscis varies from vestigial (e.g., Trichopsidea Westwood ) to extraordinarily long (e.g., Moegistorrhynchus Macquart). Bernardi (1973) monographed the world genera, though the family would benefit from an updated, comprehensive phylogenetic analysis.

Life histories of very few species are known, and all are larval parasitoids with a first instar planidial larva (Clausen, 1940; York and Prescott, 1952; Prescott, 1960; Greathead, 1958; Bernardi, 1973). Adults either don’t feed or, in ones with developed labella, they are anthophilic, feeding on flower nectar and pollen. The group occurs in xeric regions of the world, particularly deserts and Mediterranean biomes: southern South America, southern Africa, Australia; eastern Africa, the Middle East, central Asia, and western North America (Bernardi, 1973). The only tropical area with significant numbers of species is southern Asia from India to Japan and Indonesia, but this includes just about 17 species of Cyclopsideinae, in the gen- era Ceyloniola Strand (1 sp.), Nycterimyia Lichtwardt (9 spp.) and Nycterimorpha Lichtwardt (6 spp.). South Africa, by contrast, has 43 species of Nemestrinidae (Barraclough, 2006) . Here, about a dozen long-tongued nemestrinids form five guilds of monolectic to oligolectic pollinators, which collectively pollinate some 170 species of flowering plants in the Western and Northern Cape regions, particularly ones with long, narrow corolla tubes (Goldblatt and Manning, 2000; Manning and Goldblatt, 1996, 1997). The most remarkable of these guilds involves three species of the genus Moegistorrhynchus Macquart, endemic to the Western and Northern capes, which have a proboscis 90–100 mm in length—more than 3.5 times the length of the body. Like most pollinating flies, nemestrinids have exceptional flight ability, with stationary hovering required to guide the proboscis into the long, narrow corollas. Coalescence of apical wing veins, with numerous cross veins, appears to be correlated with hovering ability and length of the proboscis.

Nemestrinidae have one of the best fossil records among orthorrhaphous Brachycera, some 25 species in 13 genera from the Late Jurassic to Late Eocene. Isolated lithified wings are fortunately easily recognizable as Nemestrinidae by the diagonal vein. Bequaert and Carpenter (1936) reexamined the late Eocene species from Florissant described by Scudder and Cockerell; Evenhuis (1994) cataloged the fossil species up to 1992; Mostovski (1998) treated the Late Jurassic species from Karatau, including revisions of the taxa described by Rohdendorf; Mostovski and Martínez-Delclòs (1999) treated a diverse paleofauna from the Early Cretaceous of Spain and described further taxa from Eurasia; Ansorge and Mostovski (2000) listed all taxa known to that time. Additional taxa have been described from the Late Jurassic ( Zhang et al., 2008) and Early Cretaceous ( Ren, 1998a) of China.

The three species (two new) of Hirmoneura reported here are the first Nemestrinidae known from amber.