Neoephydra caesia (Wulp)

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 : 50-53

14. Neoephydra caesia (Wulp)

Figs. 69–71 , Map 14

Ephydra caesia Wulp 1883: 58 .

Dimecoenia caesia .— Cresson 1931: 104 [generic combination; review]; 1935: 352 [review].— Wirth 1968: 23 [Neotropical catalog].—Lizarralde de Grosso 1989: 58 [list, Argentina].— Mathis and Zatwarnicki 1995: 238 –239 [world catalog]. Neoephydra caesia .— Mathis 2008: 10 [generic combination].

Diagnosis. Specimens of N. caesia are distinguished from similar congeners of the araucaria group by the following characters: appearance generally pale, particularly the legs; face moderately setose; gena moderately high; and structures of male terminalia with distinctive conformation. Moderately large to large shore flies, body length 4.20–5.50 mm; generally dull, grayish brown to gray with some subshiny areas dorsally.

Head: Head ratio 0.65–0.68; frontal ratio 0.52–0.55; mesofrons with dark, blackish blue, metallic luster; ocellar triangle and parafrons nearly concolorous, microtomentose, brownish gray to charcoal gray; parafrons becoming more charcoal colored anteriorly; fronto-orbits with narrow strip through insertions of fronto-orbital setae subshiny, with some faint metallic luster; number of fronto-orbital setae 2. Antenna mostly concolorous, blackish brown. Facial ratio 0.86; mostly moderately setulose particularly along oral margin and toward posteroventral portions of face; dorsum of interfoveal hump with subshiny area more or less concolorous with mesofrons, otherwise face densely microtomentose, yellowish to palely brownish gray, gradually paler ventrally. Eye ratio 0.89–0.92; gena-to-eye ratio 0.39–0.41; gena moderately high, coloration gray to whitish gray but with faint tinges of olivaceous green posteriorly.

Thorax: Mostly microtomentose; mesonotum mostly blackish blue, darker and subshinier posteriorly; anterior margin more microtomentose, especially postpronotum, gray to bluish gray; pleural areas paler, more gray to grayish white ventrally; anepisternum with dorsal and posterior margins faintly brownish, otherwise faintly bluish gray; other pleural areas including coxae mostly whitish gray, concolorous. Wing length averaging 3.95–4.30 mm; mostly very faintly infuscate, palely grayish brown; costal vein ratio 0.25–0.29; M vein ratio 0.75–0.79. Legs generally pale colored; femora mostly bare, reddish yellow, hindfemur thinly microtomentose, faintly bluish to olivaceous gray; tibiae and tarsi mostly concolorous, reddish yellow.

Abdomen: Generally microtomentose and unicolorous, grayish olivaceous green to gray, becoming paler toward lateral margins, some specimens with faint bluish tinges of metallic luster; ventral surface of tergites frequently whitish gray. Tergite 5 of male somewhat trapezoidal, truncate apically. Male terminalia ( Figs. 69–71 ): margins of epandrium in posterior view narrowed below level of cerci, rounded dorsally; surstyli in posterior view roughly forming isosceles triangle, longer than wide; surstylus in lateral view with posterior process tapered gradually to narrowly rounded apex; lateral process less than 1/2 length of posterior process, more or less parallel sided, narrow, with medioapical patch of long setulae.

Type material. The neotype male of Ephydra caesia Wulp here designated is labeled “Carhue, Buenos Aires/ Argentina Dec 16 1920 /A Wetmore Collector/♂/ NEOTYPE ♂ Ephydra caesia van der Wulp by W. N. Mathis USNM [red].” The neotype is double mounted (glued to a paper point), is in good condition, and is deposited in the USNM. Nineteen paraneotypes (10♂, 9♀; USNM) bear the same locality label data as the neotype.

Type locality. Argentina. Buenos Aires: Carhué (37°11'S, 62°44'W).

MAP 14. Distribution map for Neoephydra caesia (Wulp) .

Additional specimens examined. ARGENTINA. Mendoza: Río Desaguadero (33°25'S, 67°11'W), Nov 1972, M. L. de Grosso (4♂, 9♀; FML).

Distribution (Map 14). Neotropical: Argentina (Buenos Aires, Mendoza).

Remarks. Van der Wulp described this species from a single female specimen, which is automatically the holotype, but he also studied a topotypical male. That male, according to van der Wulp, was a paler variety of the species, being smaller, more metallic green, and with legs that are entirely brownish yellow. Because van der Wulp accorded this specimen varietal status, it cannot be considered as part of the type series.

In the original description, van der Wulp stated that the holotype was collected in Argentina by Professor H. Weyenbergh, Jr. The unique specimen was apparently returned to Professor Weyenbergh in Argentina, and according to Horn and Kahle (1937: 301) all of Weyenbergh's collection was destroyed. Other holotypes apparently suffered a similar fate ( Thompson 1974: 28). Thus, it seems likely that the holotype of Ephydra caesia was destroyed.

When we began this study, we requested the holotype from the Instituut voor Taxonomische Zoologie, Amsterdam, through Dr. Theowald van Leeuwen. We were sent a “ syntype ” which was missing its abdomen. This specimen cannot be a syntype, as already noted, and although we cannot determine the sex of the specimen, it does match the brief description of the male “variety,” especially in the coloration of the legs, which are entirely brownish yellow rather than red to dark brown, the leg color of the female holotype. The specimen does bear a handwritten label, which reads “Argenta Weyenb[ergh] [handwritten, pale yellow]/ Ephydra caesia [handwritten]/ SYNTYPE [red with black border near margin].” Based on this evidence, we believe this specimen is the topotypical male variety that van der Wulp mentioned in the original description. It has no nomenclatural status, however.

As no holotype is apparently extant and as the so-called male variety is neither identifiable nor has any nomenclatural status, we have designated a neotype (see “ Type Material”).

Figures

FIGURES 69 – 71. Structures of male terminalia of Neoephydra caesia (Wulp). (69) epandrium, cerci, surstyli, posterior view; (70) same, lateral view; (71) surstylus, lateral view.