Canacidae

Female Canacea macateei, from Mathis (2010).

Belongs within: Schizophora.

The Canacidae, surf flies, are a group of small flies mostly found in intertidal habitats. Larvae are little-known but are probably grazers on algae or saprobes. The New World genus Procanace represents the sister group to the remaining genera in the family, from which it differs in the absence of intrafrontal setae (though the anterior third of the frons may bear scattered setulae). The remaining genera are divided between the Canacinae and Nocticanacinae with the latter also being restricted to the New World (Mathis 2010).

Characters (from Wirth 1987): Small pruinose flies, 3–5 mm long; blackish, brownish, yellowish, or gray in color, often with striking whitish to grayish pruinescence ventrally; wing usually without color pattern. Head large with large subcranial cavity. Clypeus prominent, usually fitting into emargination on lower margin of face. Proboscis large, with fleshy labella; palpus well-developed. First flagellomere rounded; arista dorsal, short pubescent to bare. Frons wide in both sexes; three to five pairs of divergent fronto-orbital bristles present; frontal vitta often differentiated, with or without one or more pairs of interfrontal bristles. Ocellar triangle large; ocellar bristles present and strong; postocellar bristles absent but often replaced by pseudopostocellar bristles, i.e. specialized ocellar setulae; inner and outer vertical bristles strong. Face slightly convex to concave; upper portion swollen, separating antennae, bristles usually absent except for incurved vibrissa. Gena broad; one or more upcurved genal bristles present, usually in an oblique series; subvibrissal setulae present or absent. Thorax with four or more pairs of dorsocentral bristles present; prescutellar acrostichal bristles present or absent, one pair of postpronotal bristles, one or two pairs of notopleural bristles, and one pair of presutural and usually two pairs of postsutural supra-alar bristles present; sometimes one pair of presutural intra-alar bristles present; anepisternal and katepisternal bristles present or absent; one or two pairs of scutellar bristles present. Legs rather short, without strong bristles; femora sometimes with ventral armature of short stout spines. Wing with C extending to M; Sc complete and separate from R₁ almost to its tip; C with only subcostal break; cells br, bm, dm, and cup complete; A₁ short. Male with terminalia symmetric. One pregenital segment present, formed mostly by tergite 6 but with its posterior portion possibly consisting of remnants of segments 7 and 8; sternite 6 absent; spiracles 1–6 situated just below margins of respective tergites; spiracle 7 situated in posterior part of tergite 6. Epandrium short or nearly divided medially. Surstylus fused with epandrium, in repose directed anteroventrally below abdomen, with its apex simple, hooked, or bilobate. Hypandrium broadly open or nearly closed anteriorly, posteriorly usually with a pair of lateral arms extending above aedeagus and fusing to form a backwardly directed long and acute or short and blunt spine-like process; gonopod large, weakly sclerotized, with dense fine setae; paramere rather slender, with a few preapical setae; aedeagus short, with complex sclerotisation; aedeagal apodeme slender and very long. Cercus distinct but weak. Female either with tergite 7 fused with sternite 7 and with sternite 7 divided medially and spiracle 7 enclosed in the synsclerite, or with tergite and sternite 7 separate, and with sternite 7 large and entire and spiracle 7 situated below the margin of the tergite. Tergite 8 large; sternite 8 divided medially or nearly so, each half weak except posteriorly where it bears several strong straight or curved setae. Epiproct and cerci completely fused; cerci apparently represented by a pair of long, backwardly directed, closely appressed, tapering, sometimes strongly sclerotised lobes (genital lamellae of authors); each lobe ending in a very strong seta that may be acute or blunt and flattened and may be preceded by one or more similar but smaller setae. Hypoproct small, with or without distinct hairs. Ventral wall of genital chamber with V-shaped or ring-shaped sclerite. Two spermathecae present, variable in shape.

<==Canacidae M10
    |  i. s.: Tethinosoma fulvifrons WT11
    |         Isocanace albiceps CM91
    |         Trichocanace atra O98
    |         Xanthocanace CM91
    |         Chaetocanace CM91
    |           |--C. biseta O98
    |           `--C. brincki O98
    |         Zalea CM91
    |--Procanace M10
    |    |--P. dianneae WT11
    |    |--P. gressitti O98
    |    |--P. grisescens M10
    |    |--P. nigroviridis M10
    |    |--P. novaeguineae O98
    |    `--P. opaca O98
    `--+--Canacinae M10
       |    |--Canace CM70 [Canacini M10]
       |    |    `--C. albiceps CM70
       |    `--Canacea [Dynomiellini] M10
       |         `--C. macateei M10
       `--Nocticanacinae M10
            |--Paracanace hoguei M10
            |--Canaceoides M10
            |    |--C. angulatus W87
            |    `--C. nudatus M10
            `--Nocticanace M10
                 |--N. arnaudi M10
                 |--N. chilensis M10
                 `--N. texensis M10

*Type species of generic name indicated

REFERENCES

[CM70] Colless, D. H., & D. K. McAlpine. 1970. Diptera (flies). In: CSIRO. The Insects of Australia: A textbook for students and research workers pp. 656–740. Melbourne University Press.

[CM91] Colless, D. H., & D. K. McAlpine. 1991. Diptera (flies). In: CSIRO. The Insects of Australia: A textbook for students and research workers 2^nd ed. vol. 2 pp. 717–786. Melbourne University Press: Carlton (Victoria).

[M10] Mathis, W. N. 2010. Canacidae (surf flies). In: Brown, B. V., A. Borkent, J. M. Cumming, D. M. Wood, N. E. Woodley & M. A. Zumbado (eds) Manual of Central American Diptera vol. 2 pp. 1115–1119. NRC Research Press: Ottawa.

[O98] Oosterbroek, P. 1998. The Families of Diptera of the Malay Archipelago. Brill: Leiden.

[WT11] Wiegmann, B. M., M. D. Trautwein, I. S. Winkler, N. B. Barr, J.-W. Kim, C. Lambkin, M. A. Bertone, B. K. Cassel, K. M. Bayless, A. M. Heimberg, B. M. Wheeler, K. J. Peterson, T. Pape, B. J. Sinclair, J. H. Skevington, V. Blagoderov, J. Caravas, S. N. Kutty, U. Schmidt-Ott, G. E. Kampmeier, F. C. Thompson, D. A. Grimaldi, A. T. Beckenbach, G. W. Courtney, M. Friedrich, R. Meier & D. K. Yeates. 2011. Episodic radiations in the fly tree of life. Proceedings of the National Academy of Sciences of the USA 108 (14): 5690–5695.

[W87] Wirth, W. W. 1987. Canacidae. In: McAlpine, J. F. (ed.) Manual of Nearctic Diptera vol. 2 pp. 1079–1083. Research Branch, Agriculture Canada.

Last updated: 29 June 2021.