Tethininae

Mathis, Wayne N. & Marinoni, Luciane, 2012, A conspectus on the Canacidae (Diptera) of Brazil, ZooKeys 162, pp. 59-92 : 75-76

Subfamily Tethininae

Tethinidae Hendel 1916: 297 [as a family]; 1917: 45. Type genus: Tethina Haliday. Mathis and Munari 1996: 1-27 [world catalog]. Munari and Mathis 2010: 40-66 [world catalog].

Diagnosis.

Adult. Small to moderately large flies, body length 1.43-3.66 mm; frequently invested with pale yellowish to brown microtomentum. 3-4 lateroclinate fronto-orbital setae, 3 inclinate frontal setae; postocellar seta convergent. Face sometimes characterized by 2 shiny protuberances laterad of facial cavity above vibrissal pore ( Tethina ); vibrissal seta variable, if present usually weak. 1 proepisternal seta; 1 proepimeral seta (sometimes absent in the genus Tethina ); anepisternum with 1 or more setae and some setulae posteriorly. Precoxal bridge present. Wing hyaline to infuscate or pale yellow or even patterned ( Tethina pictipennis Freidberg and Beschovski and Tethina lusitanica Munari, Almeida and Andrade); C with Sc break only; cell cup present but small; A1 weakened apically, not reaching wing margin. Tibiae lacking preapical dorsal seta. Male epandrium bearing 2 lobes ventrally (the lobe that articulates dorsally with the subepandrial sclerite is considered to be the true surstylus while the anterior surstylar-like lobe may or may not be surstylar in origin); the true surstylus is generally strongly setulose; aedeagal apodeme long, slender; ejaculatory apodeme usually large; aedeagus usually elongate, ribbonlike, sinuous, subcylindrical, with a more or less dense ventral pubescence, often with several microscopic papillae. Female with 2 sclerotized spermathecae; cercus subcylindrical or compressed, sometimes bearing strong, spinelike setulae (pseudacanthophorites); tergites 7-8 mostly with characteristic pigmented areas; epiproct generally small, bearing a pair of setulae dorsally on apical third; hypoproct large.

Natural History.

Tethininae are mostly halobiont/thalassophiles, occurring in coastal marine habitats. Adults of thalassophilous species are commonly found in coastal marine habitats ( Karl 1930; Munari and Vanin 2007), including the intertidal zone, wrack heaps (usually brown algae that are most abundant along temperate seashores bathed by cold currents), salt marshes, dune vegetation, and on salty soils or bare sand. We have also observed adults often in large numbers on carcasses of marine animals on beaches.

The immature stages of the subfamily are incompletely known. Ferrar (1987) provided some observations on the puparia of Tethina grisea ( Fallén). Gorczytza (1988) reported on the spatial and seasonal distribution of some European species ( Pelomyiella mallochi (Sturtevant), Tethina albosetulosa (Strobl), Tethina illota Haliday, Tethina flavigenis (Hendel), and Tethina grisea ( Fallén)) from a study using color traps on the Frisian Islands of Mellum and Memmert. In nature, an abundance of individuals and a paucity of species sometimes characterize sandy sites where tethinids occur.

Key to Genera of Tethininae from Brazil