Xenasteia Hardy, 1980

Grimaldi, David A., 2009, The Asteioinea of Fiji (Insecta: Diptera: Periscelididae, Asteiidae, Xenasteiidae), American Museum Novitates 3671, pp. 1-60 : 51

Genus Xenasteia Hardy

Xenasteia Hardy, 1980: 11 . Type species: X. sabroskyi Hardy , by original designation.

Tunisimyia Papp, 1980: 417 . Type species: T. excellens Papp , by original designation.

Synonymy by McAlpine, 1989: 1466 (date precedence).

DIAGNOSIS: Small, compact, dark-bodied acalyptrates with generally a metallic shine on the frons, scutum, and abdominal tergites. Head with minute pair of postocellar setae, generally 3 pairs of fronto-orbital setae (anteriormost pair inclinate); arista bare or minutely setulose, pedicel with dorsal seam. Scutum with 2 pairs of dorsocentrals, approximately 4 rows acrostichals. Wings with distinctive venation: Vein C with break near Sc, weakened near h (but no humeral break, contra Hardy, 1980); R 2+3 short; vein M past level where R 2+3 and R 4+5 fork is evanescent, represented by row of microtrichia; Cu present, incomplete; anal veins lost. Male terminalia distinctive but uniform: with pair of large lobes on posterior margin of hypandrium, which project posteriad and bear apical pair of minute, spinelike setulae; pair of long, projecting surstyli also present; aedeagus small, mostly membranous; male pregenital sclerites asymmetrical, well developed (tVII?) on right side.

COMMENTS: Based on the collecting data, Xenasteia spp. appear to be associated with xeric, sandy habitats, particularly seashores and near-shore habitats. They commonly come to light ( Hardy, 1980; Ismay, 2003; Papp, 2005), and congregate on xeric vegetation, but also have been found on decaying fish ( Hardy, 1980; Ismay, 2003). The vegetation from which they have been collected are tamarisk ( Tamarix ) trees ( Freidberg, 1994; Carles-Tolrá, 1995), Chrithanemum maritimum stems ( Papp, 1980), and decaying leaves of Pandanus (Pandanaceae) ( Hardy, 1980; Ismay, 2003). These plants are associated with saline and maritime habitats. Interestingly, the new Fiji species is probably the only one to have been collected using Malaise traps, but from a unique environment in Fiji: the Sigatoka Sand Dunes, of which large stands of Pandanus occur nearby. Systematic collecting at Sigatoka using light traps will probably yield a large series of Xenasteia .