Callomyia corvina Kessel

Cumming, Heather J. & Wheeler, Terry A., 2016, Revision of the Nearctic species of Callomyia Meigen (Diptera: Platypezidae) and phylogeny of the genus, Zootaxa 4111 (5), pp. 501-554 : 523-527

Callomyia corvina Kessel

( Figs 10 , 20 , 28 , 36 , 48 , 54 , 60 , 73 )

Callomyia corvina Kessel, 1948: 140 . Type locality: Marin County, California, USA.

Callomyia clara Kessel, 1948: 146 . Type locality: Marin County, California, USA. syn. nov.

Diagnosis. This western Nearctic species is characterized by its thoracic and abdominal colour patterns and male terminalia with a broadly lamellate surstylus and simple hypandrial process without projections. The female is distinguished by its distinctive thoracic colour pattern that is mainly silver-blue dusted with a black median dorsal stripe on the scutum and by its abdominal silver-yellow or silver-blue markings on tergites 1−4 and 6. The male is distinguished by its abdominal silver bluish-grey markings on tergites 1–5 and sometimes 6, yellowish-brown tinted wing, and features of the terminalia mentioned above. The male of C. corvina is similar to the western Nearctic species C. gilloglyorum , but differs in colour, terminalia, shape of the first flagellomere, and setae on the notopleuron and mid tibia, as indicated in the key to species.

Description. Male ( Figs 10 , 20 ). Body length 4.0– 4.2 mm; wing length 3.0–4.0 mm. Head dark silver-grey; mouthparts brownish-yellow with palpus pale yellow; antenna with scape, pedicel, first flagellomere and arista dark grey to dark brown. Antenna with first flagellomere short-oval (as in Fig. 41 ).

Thorax mainly dark brown to black with indistinct silver-grey dusting on lateral portion of presutural scutum, notopleuron, supra-alar area of scutum and postalar callus; propleuron, mesopleuron, metapleuron, mediotergite and laterotergite silver-grey; postpronotal lobe yellowish-brown posteroventrally. Scutum with 6 notopleural setae.

Legs yellowish-brown to brown with tarsomeres 4 and 5 dark brown, hind leg with apex of femur and base of tibia brownish-yellow; coxae silver-grey dusted. Mid tibia with median anterodorsal seta present in most specimens, median dorsal seta present (as in Fig. 49 ); base of hind femur with long thin posteroventral seta ( Fig. 54 ). Hind tarsomere 1 long, slightly narrower than apical width of hind tibia, length approximately 3X width.

Wing yellowish-brown tinted ( Fig. 48 ). Halter orange with base of stem brown.

Abdomen black to velvety black with lateral dark silver bluish-grey markings on tergites 1–4; ventrolateral dark silver bluish-grey marking on tergite 5; ventrolateral silver-grey marking on tergite 6; tergite 7 entirely brown to grey; sternites light brown, sternite 8 brown to grey.

Terminalia ( Fig. 60 ) with epandrium and hypandrium grey; surstylus brown; hypandrial process and cercus brownish-yellow. Epandrium with moderately long narrow ventral lobe, curved posteriorly, blunt at apex; apical process short, broad at apex. Surstylus broadly lamellate with narrow ventral process; dorsal lobe lengthened with slightly truncate apex; ventral process moderately long, straight. Hypandrium with elongate slender apical process; process simple and pointed at apex, without apical projections and basoventral lobe. Postgonite long, slightly expanded apically, truncate at apex. Phallus slightly curved towards apex, without sharp hook. Cercus short.

Female ( Figs 28 , 36 ). Body length 2.9–3.85 mm; wing length 2.75–4.1 mm. Head silver-blue with coppery reflections on occiput and gena in some specimens, postgena pale-yellow in some specimens; mouthparts including palpus pale yellow to yellow; antenna with scape and pedicel brown to brownish-yellow, pale yellow apically, first flagellomere and arista entirely brown. Antenna with first flagellomere short-oval (as in Fig. 43 ).

Thorax mainly silver-blue dusted; postpronotal lobe brownish-yellow; scutum with median dorsal stripe and supra-alar area black; scutellum mostly black, brownish-yellow basolaterally. Scutum with 2–4 presutural intraalar setae.

Fore leg and mid leg pale yellow to yellow with tarsomeres yellowish-brown in most specimens; hind leg darker with apex of femur, tibia and tarsomeres yellowish-brown to brown. Mid tibia with short median dorsal seta present in most specimens (as in Fig. 52 ).

Wing hyaline with cell sc bluish-white in some specimens. Halter pale yellow to yellowish-orange.

Abdomen dark brown to black with tergites 1, 2 and 6 entirely silver-yellow or silver-blue; posterior silveryellow or silver-blue markings on tergites 3 and 4, marking on tergite 4 interrupted by median dorsal dark band in most specimens; sternites pale yellow to pale orange.

Terminalia with segment 8 brown; epiproct brown, hypoproct and cercus yellow to yellowish-brown.

Type material. Callomyia corvina Kessel , HOLOTYPE, ♂ labelled: “Mill Valley,/ Marin Co. Cal./ 10-5-45; “E.L. Kessel/ Collector; “ HOLOTYPE [red label]; “ Callomyia / corvina / Kessel/ 5997 [on left hand edge] [pink label]; “California Academy/ of Sciences/ Type No. 5997 [dissected] ( CAS). PARATYPE: USA: CALIFORNIA: same data as holotype except 25.x.1945 (1 ♂, CAS).

Callomyia clara Kessel , HOLOTYPE, ♀ labelled: “Mill Valley,/ Marin Co. Cal./ 11-5-45; “E.L. Kessel/ Collector; “ HOLOTYPE [red label]; “ Callomyia / clara / Kessel/ 6000 [on left hand edge] [pink label]; “California Academy/ of Sciences/ Type No. 6000 ( CAS).

Additional material examined. USA: CALIFORNIA: Amador County, 4 mi. E. of Volcano, 2.x.1960, E.L. Kessel (1 ♂, CAS); Amador County, Indian Grinding Rock St. Pk., dry wash nr. S. Nature trail, 3825’ N12038 ’W, MT# 2, 715 m, 3.iv-15.v.2008, P. Kerr, CSCA 08L335 (1 ♂, CNC); El Dorado County, Eagle Falls, 18.ix.1960, E.L. Kessel (1 ♂, CAS); Humboldt County, Grizzly Creek Redwoods State Park, 23.ix.1960, E.L. Kessel (1 ♀, CAS); Los Angeles County, Pasadena, 2.xi.1949, E.L. Kessel (1 ♀, CAS); Los Angeles County, Topanga Cyn., 34.08N 118.59W, 6–20.xii.1993, Malaise trap, B. Brown & G. Hendler (1 ♀, LACM); Los Angeles County, 9 km N. La Canada, 34.25N 118.19W, 16-30.xi.1994, Malaise trap 900 m, B. Brown (1 ♀, LACM), same except 30.xi- 14.xii.1994 (1 ♀, LACM); Marshfield, 14.ix.1934, A.L. Melander (1 ♀, USNM); Monterey County, Nacimiento Canyon Camp, 9.x.1960, E.L. Kessel (1 ♀, CAS); Riverside County, El Cariso Camp Ground, 1.iv.1961, E.L. Kessel (1 ♂, CAS); Riverside County, Upper San Juan Forest Camp, 6.xii.1961, E.L. Kessel (1 ♀, CAS); Riverside County, Upper San Juan Camp Ground, 1.iv.1961, E.L. Kessel (1 ♀, 1 ♂, CAS); San Bernardino County, Thurman Flats, 22.x.1965, P.H. Arnaud Jr. (1 ♂, CAS); Shasta County, Castle Creek, 18.x.1959, E.L. Kessel (1 ♂, CAS); Stanislaus County, Del Puerto Canyon, Frank Raines Park, 1120’, 3.iv.1970, P.H. Arnaud Jr. (1 ♂, CAS), same except 335 m, 5.iv.1970 (1 ♀, CAS); IDAHO: Moscow Mountain, 9.vii.1920, A.L. Melander (1 ♀, USNM); OREGON: Lane County, Limberlost Forest Camp, Hwy. 126, 6.ix.1962, E.L. Kessel (1 ♂, CAS); WASHINGTON: Mt. Rainier, Longmire, 20.vii.1922, A.L. Melander (1 ♀, USNM).

Geographical distribution and seasonal occurrence ( Fig. 73 ). Callomyia corvina is currently known from western USA (Washington, Idaho, Oregon and California). Adults have been collected from early April, July and September to mid-December.

Remarks. Callomyia corvina is most closely related to the widespread Palaearctic species C. speciosa , as shown in the strict consensus tree ( Fig. 79 ). These two species have similar male terminalia and female abdominal colour pattern. However, the male terminalia of C. corvina have a broadly lamellate surstylus with a longer and thinner ventral process and a wider hypandrial process. The female abdominal markings of C. corvina differ by the silvery yellow or blue colour on tergite 4 being interrupted by a median dorsal dark band, which is uninterrupted in C. speciosa .

Callomyia corvina and Callomyia clara were described from one sex only by Kessel (1948) with C. corvina described from males and C. clara described from a female. Both species are considered to be conspecific because they have been collected from many of the same localities, including the type locality, at or around the same time.

The names C. corvina Kessel and C. clara Kessel are now considered subjective synonyms and were published in the same work ( Kessel 1948). As First Reviser (Article 24.2.2, ICZN 1999) the name C. corvina Kessel is herein selected as having precedence over C. clara Kessel.

Figures

FIGURE 73. Known distribution of C. corvina.

FIGURE 79. Strict consensus tree of the 136 most parsimonious cladograms of the world species of Callomyia and outgroups, produced by the analysis of the data matrix in Table 2. Bremer support values are listed above each internode. The Oriental species, Callomyia coei Kessel and C. triangulata Tkoč, were excluded from the analysis because they are only known from females.

FIGURES 9 − 14. Callomyia males, lateral view. 9. C. calla. 10. C. corvina. 11. C. gilloglyorum. 12. C. proxima. 13. C. velutina. 14. C. venusta.

FIGURES 19 − 24. Callomyia males, dorsal view. 19. C. calla. 20. C. corvina. 21. C. gilloglyorum. 22. C. proxima. 23. C. velutina. 24. C. venusta.

FIGURES 25 − 28. Callomyia females, lateral view. 25. C. arnaudi (pale orange on tergites 1 – 2 mostly obscured in photograph by silver-white dusting). 26. Possible C. bertae female. 27. C. calla. 28. C. corvina.

FIGURES 33 − 36. Callomyia females, dorsal view. 33. C. arnaudi (pale orange on tergites 1 – 2 mostly obscured in photograph by silver-white dusting). 34. Possible C. bertae female. 35. C. calla. 36. C. corvina.

FIGURES 45 − 48. Callomyia thoracic bristles and wings. 45. C. velutina, female (scutum with 3 presutural intra-alar setae). 46. C. venusta, female (scutum with 2 presutural intra-alar setae). 47. C. argentea, male wing. 48. C. corvina, male wing.

FIGURES 49 − 54. Callomyia legs. 49. C. proxima, male mid leg (with tibial setae). 50. C. velutina, male mid leg (with tibial seta). 51. C. proxima, female mid leg (with tibial seta). 52. C. velutina, female mid leg (with tibial seta). 53. C. argentea, male hind leg (with femoral seta). 54. C. corvina, male hind leg (with femoral seta). Abbreviations: ad s—anterodorsal seta; d sdorsal seta; pv s—posteroventral seta.

FIGURES 59 − 62. Callomyia male terminalia, lateral view. 59. C. calla. 60. C. corvina. 61. C. gilloglyorum. 62. C. proxima. Scale bar = 0.1 mm.

FIGURES 41 − 44. Callomyia antennae. 41. C. calla, male antenna (first flagellomere short-oval). 42. C. gilloglyorum, male antenna (first flagellomere elongate-conical). 43. C. venusta, female antenna (first flagellomere short-oval). 44. C. gilloglyorum, female antenna (first flagellomere subtriangular).