Setacera pilicornis (Coquillett)

Mathis, Wayne N. & Marinoni, Luciane, 2016, Revision of Ephydrini Zetterstedt (Diptera: Ephydridae) from the Americas south of the United States, Zootaxa 4116 (1), pp. 1-110 : 102-104

32. Setacera pilicornis (Coquillett)

Figs. 139–145 , Map 32

Ephydra pilicornis Coquillett 1902: 184 .

Setacera pilicornis .— Sturtevant and Wheeler 1954: 204 [generic combination].— Wirth 1968: 24 [catalog, distribution].— Mathis 1982b: 49 –53 [revision, Figs. of head, thorax, ♂ terminalia].— Mathis and Zatwarnicki 1995: 254 [world catalog]. Setacera knabi Cresson 1935: 346 .— Sturtevant and Wheeler 1954: 204 [synonymy].

Diagnosis. This species is similar to other species of the pacifica group, especially S. trichoscelis Mathis , but is distinguished by the following combination of characters: Overall body coloration more bluish gray; antennal grooves sparsely microtomentose, subshiny, nearly concolorous with dorsum of hump; vertico-orbits with velvety microtomentum very narrow, inconspicuous; postpronotal seta weak, length less than 1/2 presutural seta; distance between presutural seta and posterior notopleural seta slightly less than between notopleural setae; forecoxa lacking shaggy-appearing setulae; fore- and midtibiae mostly dark and concolorous with femora, at most with tibial-femoral articulation pale; midtibia of male lacking apical tufts of long hairs; tergite 5 of male longer than either tergites 3 or 4, narrowly to bluntly rounded, width at apex much less than length; sternites 3 and 4 of male usually with dense patch of stout setae toward posterior margin; conformation of male terminalia (Figs.?) unique; females with 6 visible abdominal segments from dorsal view. Medium-sized to moderately large shore flies, body length 3.30–4.10 mm; subshiny to shiny dorsally, with faint to distinct, greenish blue to bluish green metallic luster.

Head ( Fig. 139 ): Head ratio 0.56–0.57; frontal ratio 0.52–0.55; mesofrons luster metallic blue to greenish blue, occasionally bluish green; a large patch of thinly scattered, pilose hairs on either side of frons midline; parafrons dull, charcoal gray in color; ocelli in isosceles triangle, distance between posterior pair shorter than between medial ocellus and either posterior ocellus; fronto-orbital plates concolorous with mesofrons, shiny. Antenna black, with considerable grayish vestiture; basal flagellomere slightly longer than combined length of scape and pedicel. Face mostly silvery white except for dorsal shelf; antennal groove and interfoveal space concolorous, with metallic luster similar to mesofrons coloration; area immediately surrounding base of antenna with some dull, grayish color; lower portion of face receding, facial angle in profile approximately 110°; length of lower portion longer than distance between base of antenna and facial angle. Eye ratio 0.78–0.83, oval, with oblique orientation to epistoma.

Thorax ( Fig. 140 ): Mesonotum dull, microtomentose to subshiny, generally dark brown but with some shiny metallic luster; anterior portion duller, progressively darker and shinier posteriorly; pleural areas olivaceous brown to grayish brown; anepisternum and anepimeron generally concolorous, with some brownish coloration dorsally; katepisternum concolorous with ventral portion of anepisternum; forecoxa mostly gray, somewhat shiny. Femora concolorous, mostly dull, grayish blue, heavily microtomentose, apices pale; tibiae blackish blue, less microtomentose than femora; tarsomeres mostly black; legs of both sexes rather plain, lacking tufts of long hairs toward the apices of mid- and hindtibiae. Costal vein ratio 0.26–0.28; M vein ratio 0.80–0.83.

Abdomen: Mostly unicolorous, usually grayish blue but often with considerable brownish green coloration; posterior margins of segments often more subdued, paler. Tergite 5 of male almost as long as combined length of 3rd and 4th segments; lateral margins tapered gradually to truncate apex which is almost half the width of base. Male terminalia ( Figs. 141–143 ): epandrium more or less parallel sided; surstyli attached basally to ventral margin of epandrium, fused medially but with acutely-angled apical processes; aedeagus rather bulbous, broadly produced, rounded apically; sternite 5 more or less U-shaped, each posteroventral arm produced into well-sclerotized, sharply-angled processes. Female terminalia, including female ventral receptacle, as in Figs. 144–145 .

Type material. The holotype male of Ephydra pilicornis is labeled “ BISC [ ANYE]. BAY, FL[ ORID]A.: Mrs [Annie T.] Slosson, Collector/ Type No 6645, U.S. N.M. [red].” The holotype is in good condition and is deposited in the USNM (6645).

The holotype male of Setacera knabi is labeled “Miami, 23.11.12 [23 Feb 1912] Fl[orid]a/ Fredk Knab, Collector/♂/ TYPE No., Setacera KNABI ♂/E. T. Cresson, Jr. [pink], Type No, 51098, USNM [red].” The holotype is in good condition and is deposited in the USNM (51098).

Type locality. United States. Florida. Biscayne Bay (25°33.5'S, 80°12.6'W).

Additional specimens examined. BAHAMAS. New Providence: Carmichael area (25°01'S, 77°25'W; black light in Caribbean pine forest and scrub), 17 Apr 2007, J. M. Swearingen, W. E. Steiner (1♀; USNM); Coral Harbour (24°59'S, 77°29'W; black light in gap of scrub forest near beach), 16 Apr 2007, W. E. Steiner, J. M. Swearingen (1♂; USNM).

CUBA. Matanzas: Playa Larga (1 km E; 22°15.9'N, 81°09.9'W), 2 May 1983, W. N. Mathis (7♂, 19♀; USNM).

JAMAICA. Manchester: near Clandon (18°09'N, 77°28.3'W), 8 May 1996, D. and W. N. Mathis, H. Williams (1♀; USNM).

MEXICO. México: La Marquesa, Las Cruces Park (19°17.8'N, 99°22.2'W), 5–9 Jul 1965, O. S. Flint, Ortiz (1♀; USNM). Tabasco: Villahermosa (17°59'N, 92°55'W), 6 Aug 1964, P. J. Spangler (3♂, 5♀; USNM).

Distribution (Map 32). Nearctic: USA (Florida, Georgia, Louisiana, Mississippi, South Carolina). Neotropical: Bahamas, Mexico ( México, Tabasco), West Indies ( Cuba, Jamaica).

MAP 32. Distribution map for Setacera pilicornis (Coquillett) .

Natural history. Numerous specimens of this species were collected as prey of sphecid wasps on St. Catherines Island, Georgia (the wasps were being studied behaviorally and ecologically by Dr. R. W. Matthews and students, University of Georgia).

Remarks. When Sturtevant and Wheeler (1954) reviewed the Nearctic species of Setacera , they tentatively listed S. knabi Cresson as a junior synonym of S. pilicornis . Their uncertainty was because the type specimen of S. knabi , stated to be in the USNM, could not be located and studied. The type was subsequently located by Drs. Selwyn S. Roback and Willis W. Wirth among specimens at the Academy of Natural Sciences of Philadelphia that were not returned to the institution of deposition following the untimely death of E.T. Cresson, Jr. We examined the types of both synonyms and can confirm their conspecificity and thus, the status of S. knabi as a junior synonym. Only one species of Setacera is known to occur in Florida.

Although Coquillett's original description of this species indicates only a single male specimen, which automatically becomes the holotype, the Academy of Natural Sciences of Philadelphia collection contains four additional specimens labeled as paratypes with Cresson's blue labels. These specimens cannot be paratypes since Coquillett's description specifically lists a single male specimen.

Figures

FIGURES 139 – 140. Setacera pilicornis (Coquillett). (139) head, lateral view; (140) mesonotum, dorsal view (from Mathis 1982).

FIGURES 141 – 145. Setacera pilicornis (Coquillett). (141) male terminalia, lateral view; (142) internal structures of male terminalia, lateral view; (143) surstyli, posterior view; (144) female ventral receptacle, lateral view; (145) female terminalia, lateral view (from Mathis 1982).