Cirrula Cresson, 1915

Mathis, Wayne N. & Sepúlveda, Luciane Marinoni and Tatiana A., 2025, Phylogeny and taxonomy of the shore-fly tribe Ephydrini with comments on related tribes in Ephydrinae (Diptera: Ephydridae), Zoologia (e 24044) 42, pp. 1-42 : 15

Cirrula Cresson, 1915

Figs 16–23

Cirrula Cresson 1915: 70 (feminine; type species: Cirrula gigantea Cresson , by monotypy). – Sturtevant and Wheeler 1954: 162– 163 [review]. – Wirth 1965: 753 [Neotropical catalog]. – Mathis and Simpson 1981: 8–29 [revision of North American species, natural history]. – Mathis and Zatwarnicki 1995: 236–237 [world catalog].

Pogonephydra Hendel 1917: 42 [type species: Pogonephydra chalybea Hendel (= C. gigantea ), by monotypy] [Synonymy by Hendel 1931: 10].

Hydropyrus Cresson 1934: 216 [type species: Ephydra hians Say , by original designation and monotypy]. – Sturtevant and Wheel- er 1954: 171 [review; as subgenus of Ephydra ]. – Wirth 1965: 753 [Nearctic catalog]; 1971: 374–376 [review, figures of male terminalia; as subgenus of Ephydra ]. – Mathis and Zatwarnicki 1995: 236 [synonymy].

Diagnosis. Cirrula is distinguished from other genera of Ephydrini by the following characters: Moderately large to large shore flies, body length 4.83–8.52 mm.

Head: Cruciate, interfrontal setae 1–2 pairs, size generally subequal to fronto-orbital setae (weakly developed in C. gigantea , especially females); lateroclinate, fronto-orbital setae either 2 or 3–4 pairs, slightly divergent, if two, then dorsocentral setae (1+4), if 3–4, then dorsocentral setae (2+4); antenna simple, lacking secondary seta inserted on lateral surface just below arista; arista bare to macropubescent; face uniformly setose with marginal setae larger, declinate, one species with patches of long setae above middle height of face on anterior surface of interfoveal hump.

Thorax: Prescutellar, acrostichal setae variable; dorsocentral setae 5–6 pairs (5 (1+4) in specimens with two fronto-orbital setae, 6 (2+4) in specimens with 3–4 fronto-orbital setae), well developed in Neotropical species; supra-alar seta present; presutural supra-alar seta variable; intrapostalar seta well developed. Costal vein ratio 0.18–0.19; M 1 vein ratio 0.95–1.10. Legs sexually dimorphic; hindtibia lacking apical, long seta; pulvilli greatly reduced or essentially absent; tarsal claws long and nearly straight.

Abdomen: Male terminalia symmetrical; surstyli complex, situated at ventral apex of epandrium, covering other internal structures in repose, fused medially; phallapodeme more or less C-shaped with a dorsal lobe extended far into epandrial cavity; aedeagus generally simple except in males of C. austrina , where trilobate process arises at anterior base of aedeagus. Female ventral receptacle with large operculum, generally as high as wide; extended process J-shaped, length about as long as height of operculum; conformation of receptacle in females of D. spinosa exceptional, operculum trapezoidal and much smaller, extended process three times as long as operculum length.

Third-instar larva: Prolegs distinct, better developed than those of Ephydra species; segment 3 of third-instar larvae with distinctive transverse band on venter.

Natural History: Mathis and Simpson (1981) published a detailed report on the natural history of C. austrina (Coquillett) . They successfully reared specimens from several localities along the coast of Virginia and noted that immatures and adults reached their highest densities where the habitat was partially dried, leaving algal mats on firm ground. Adults were collected commonly by sweeping over these mats.

Unlike the larvae of Dimecoenia spinosa , those of C. austrina have eight pairs of well-developed prolegs and the third-instar larva also has a dark transverse strap at the anteroventral margin of segment three.

Aldrich (1912) and Hutchinson (1937) provided excellent and detailed accounts of the biology of the so-called “alkali-fly,” C. hians (Say) . The larvae are usually found on the bottom of the water in pools of water where they feed and do not come to the surface. The puparia attach to any available object. In storms, the puparia detach and form wind rows along the shore.

Distribution. New World. Primarily the temperate western region of the Nearctic Region but with a southward extension into the northern Neotropical Region ( Belize (Stann Creek District )).

Remarks. Cirrula now comprises four species ( C. austrina (Coquillett) , C. currani (Wirth) , C. gigantea Cresson , and C. hians (Say)) and is similar and closely related to the genus Dimecoenia .

Figures

Figures 16–23. Cirrula. Cirrula hians, (16) head anterior; (17) head lateral; (18) thorax dorsal. Cirrula austrina, (19) thorax dorsal; (20) hind leg anterior; (21) male terminalia lateral; (22) male surstyli posterior; (23) ventral receptacle lateral.