Ephydra (Halephydra) gracilis Packard

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 : 95-97

30. Ephydra (Halephydra) gracilis Packard

Figs. 130–132 , Map 30

Ephydra gracilis Packard 1871: 105 .— Aldrich 1912: 78 [biology, description].— Mathis and Zatwarnicki 1990b: 903 [revised status]; 1995: 243 [world catalog].

Ephydra cinerea Jones 1906: 159 .— Sturtevant and Wheeler 1954: 168 [distribution, notes, synonymy].—Wirth 1956: 19 [distribution in Bahamas]; 1968: 22 [Neotropical catalog].

Ephydra (Halephydra) cinerea .— Wirth 1971: 371 –374 [revision].— Simpson 1976: 264 [description and Figs. of larva and puparium].

Diagnosis. This is the only known species of the subgenus Halephydra that is known to occur in the Caribbean basin and is distinguished by the following combination of characters: cruciate interfrontal setae weak or lacking; crossvein dm-cu forming acute angle with vein CuA1; palpus relatively small; mesonotum strongly microtomentose, whitish gray. Medium-sized to moderately large shore flies, body length 3.00– 4.60 mm; general coloration gray, often with some faint greenish or bluish gray.

Head: Head ratio 0.71–0.75; frontal ratio 0.60–0.63; mesofrons with luster. Facial ratio 0.95–1.00. Eye ratio 0.93–0.96; gena-to-eye ratio 0.39–0.43; gena relatively high, concolorous with face.

Thorax: Scutum (vestiture and coloration); scutellum (shape). Acrostichal setae; prescutellar area of female; anepisternum (setae along posterior margin). Wing length 2.10–3.20 mm; costal vein ratio 0.34–0.36; M vein ratio 0.65–0.69.

Abdomen: Male terminalia ( Figs. 130–132 ): As described under the subgenus.

Type material. This species was originally described from puparia, and these have apparently been lost. Dr. Norman D. Woodley (personal communication) conducted a thorough search of the alcoholic collections at the Museum of Comparative Zoology and could not find the specimens of E. gracilis that Packard had studied.

Specimens of E. gracilis were found that were collected in 1871 by a J. A. Allen, and Packard could have studied these. But as Mr. Allen is not one of the collectors Packard mentioned in the original description, these specimens cannot be considered as part of the type series.

The lectotype male of Ephydra cinerea Jones (designated by Arnaud 1979: 349) is labeled “Ƌ/Redondo Los Angeles Co V-23-98 [23 May 1898]/1169/ LectoTYPE Ephydra CINEREA Jones /6 Ephydra [a manuscript name] n. sp./ Ephydra var gracilis Pack. det. Cresson 1919/ LECTOTYPE Ƌ Ephydra cinerea Jones det 1974 PHArnaud & VFLee.” The lectotype, allolectotype, and two paralectotypes are deposited in the CAS (4108).

Type locality. United States. Utah. Salt Lake: Great Salt Lake (40°45'N, 112°12.9'W).

Additional specimens examined. ANGUILLA. Prickly Pear Island (18°20.5'N, 63°74.8'W), 28 Mar 1958, J. F. G. Clarke (9♂, 15♀; USNM). Rendezvous Salt Pond (18°10.8'N, 63°06.7'W), 26 Mar 1992, W. E. Steiner, J. M. Swearingen (17♂, 23♀; USNM).

BAHAMAS. Exuma Cays: Staniel Cay (Staniard Cay; 24°14'N, 76°26'W), 13 Jan 1953, E. B. Hayden (50♂, 50♀; AMNH).

CURAÇAO. Koraal [Coral] Specht (3 km E Willemstad; 12°04.9'N, 68°52.9'W), 8–15 Feb 1987, W. E. Steiner, J. M. Swearingen (3♂, 13♀; USNM).

DOMINICAN REPUBLIC. Monte Cristi: Monte Cristi (19°51.5'N, 71°31.5'W; salt works), 18 May 1995, W. N. Mathis (3♂, 4♀; USNM).

JAMAICA. Clarendon: Rocky Point (2 km S; near Jackson Bay Cave; black pale; 17°44'N, 77°14'W), 10 Dec 1975, G. F. Hevel (1♂; USNM). St. Thomas: Yallahs salt ponds (17°51.8'N, 76°31'W), 14 May 1996, D. and W. N. Mathis, H. Williams (9♂, 6♀; USNM).

MEXICO. Baja California: Tijuana (72 km S; 30°24'N, 116°W), P. H. Arnaud, Jr. (ex; CAS). Baja California Sur: Isla del Carmen, Gulf of California (26°N, 111°08.6'W), 18–19 Jul 1984, S. E. Miller (1♂; USNM); Puerto Refugio (29°39.9'N, 11333.9'W), Isla Angel de la Guardia, M. C. Van Duzee (ex; CAS); San José del Cabo (23°03'N, 109°41'W), A. E. Michelbacher, E. S. Ross (ex; CAS); Todos Santos (29°30'N, 114°45'W), C. Ewart, R. C. Dickson (ex; UCR). Guerrero: Acapulco (16°50'N, 99°53'W), J. Chillcott (ex; CNC). Nayarit: San Blas (22°52'N, 105°06'W), 3 Jul 1964, P. J. Spangler (1♂; USNM). Oaxaca: Tehuantepec (16°20'N, 95°14'W; at light trap), 15–23 Jul 1964, P. J. Spangler (1♂; USNM). Sinaloa: Mazatlán (23°13'N, 106°25'W), 1–23 Jul 1963, 1964, P. J. Spangler (19♂, 27♀; USNM). Sonora: Álamos (27°01.6'N, 10856.4'W), P. H. Arnaud, Jr. (ex; CAS); Bahía Kino (28°47'N, 111°58'W), P. H. Arnaud, E. S. Ross, D. Rentz (ex; CAS); Ciudad Obregón (27°29'N, 110°W; San Jose beach), H. Howden, Martin (; CNC); El Desemboque (29°30'N, 112°23'W), B. Malkin (ex; CAS); Rocky Point (Puerto Peñasco; 31°19.1'N, 113°32.2'W), A. L. Melander (ex; CAS).

NAVASSA ISLAND. ruins near Lulu Bay (18°23.75'N, 75°01.07'W; 22 m), 29 Jul 1998, W. E. Steiner, J. M. Swearingen (1♂, 2♀; USNM).

PUERTO RICO. Bahía Salinas (beach; 17°57.5'N, 67°12'W), 20 Sep 1995, D. and W. N. Mathis (2♂; USNM). Ensenada (17°58.2'N, 66°55.7'W), Nov 1936, Martoreli, G. Wollcott (43♂, 51♀; USNM). Guanica (17°59.3'N, 66°54.4'W), 22 Jul 1952, F. S. Blanton (1♂, 2♀; USNM). Río Grande (18°21.1'N, 65°48.4'W), 11–12 Mar 1964, S. M. Gaud, G. Rivera (2♂, 1♀; USNM).

TRINIDAD. St. George: Chacachacare Island (10°41'N, 61°46'W), 29 Jun 1993, W. N. Mathis (17♂, 9♀; USNM).

TURKS and CAICOS. Providenciales: Crystal Bay (near North West Point; 21°50'N, 72°19'W; sandy scrub forest), 31 Jan 1998, W. E. Steiner, J. M. Swearingen (1♀; USNM).

VIRGIN ISLANDS. St. John: Coral Bay (18°20.9'N, 64°43'W), 22 Jan 1963, P. J. Spangler, Muller (17♂, 20♀; USNM).

Distribution (Map 30): Australasian/Oceanian: Hawaiian Islands (Kauai, Oahu). Nearctic: United States (Arizona, California, Kansas, Nevada, New Mexico, Ohio, Texas, Utah). Neotropical: Bahamas, Curaçao, Mexico (Baja California, Baja California Sur, Guerrero, Nayarit, Oaxaca, Sinaloa, Sonora), Trinidad, Turks and Caicos, West Indies ( Anguilla, Dominican Republic, Dutch West Indies, Jamaica, Navassa Island, Puerto Rico, Virgin Islands).

Remarks. Our usage of the name E. gracilis , as the senior synonym for this species, reverses a trend established by Sturtevant and Wheeler (1954) when they gave precedence to E. cinerea Jones and listed E. gracilis as a questionable synonym. Sturtevant and Wheeler argued, incorrectly paraphrasing Aldrich (1912), that Packard's description of the “larva [sic, Packard described the puparium] does not agree with the present species--a point that we can confirm.” we have reexamined the available data and have concluded that E. gracilis can indeed be recognized, and as this name has age priority we have recognized it as the senior synonym. Our argument is as follows.

Packard's description of the puparium, although brief, does mention a few salient characters that are unique to this species. The respiratory tube is much longer than that of any other species, “being as long as the body.” The body is generally smaller and more slender, and the “feet” (prolegs) are more prominent. In addition, as Packard also noted, this species occurs abundantly around the Great Salt Lake. This combination of characters does describe this species adequately, and it is the most abundant species known to occur around the Great Salt Lake.

Aldrich (1912: 79), contrary to Sturtevant and Wheeler's incorrect paraphrasing of his work, did not say that Packard's description “does not agree with the present species.” Instead, Aldrich noted the brevity of Packard's description and that the description was “scarcely” recognizable and unsatisfactory by the omission of a striking distinction (the basal filaments of the “anal” tube). Nevertheless, Aldrich concluded that “it is certain that Packard was describing a strikingly small Ephydra common in Great Salt Lake, and there is but one species [ E. gracilis ], whether he [Packard] described it well or not.”

As we believe that the puparia Packard described can be recognized, and as E. gracilis has distinct age priority by over thirty years, we can only conclude that this species is recognized by the name its original describer gave, i.e., E. gracilis .

MAP 30. Distribution map for Ephydra gracilis Packard.

Figures

FIGURES 130 – 132. Structures of male and female terminalia of Ephydra gracilis Packard. (130) epandrium, cerci, surstyli, posterior view; (131) same, lateral view; (132) aedeagus, aedeagal apodeme, gonites, hypandrium, dorsal view.