Callomyia arnaudi Cumming

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 : 512-514

Callomyia arnaudi Cumming sp. nov.

( Figs 5, 6 , 16 , 23 , 33 , 56 , 71 )

Diagnosis. This southwestern Nearctic species is characterized by striking metallic bluish-white colour on the thorax and abdomen, and male terminalia with a broadly lamellate surstylus. The male is similar to the southwestern Nearctic species C. bertae , except for differences in colour and terminalia that are indicated in the key to species. Callomyia arnaudi has similar male terminalia to the western Nearctic species C. gilloglyorum , but the ventral process of the broadly lamellate surstylus is shorter in C. arnaudi , as well as the apical projections and basoventral lobe of the hypandrial process. The female of C. arnaudi is similar to C. velutina , from eastern and western North America, because of its similar thoracic and abdominal colour pattern, but can be distinguished from this species by differences in colour (metallic bluish-white versus silver-blue, and pale orange on tergites 1 and 2 versus yellow on tergites 1−3). The coloured abdominal segment interrupted by a median dorsal dark band is on tergite 4 in C. arnaudi as opposed to tergite 5 in C. velutina . The female abdominal colour pattern of C. arnaudi is also similar to that of C. gilloglyorum with light colouration on tergites 1, 2, 4, 6 and 7, and dark drown to black on tergites 3 and 5. However, the actual abdominal colour between the females of these species differs (pale orange versus silver-grey on tergites 1 and 2, and metallic blusih-white versus silver-grey on tergites 4, 6 and 7).

Description. Male ( Figs 5, 6 , 16 ). Body length 3.35–3.85 mm; wing length 3.3–3.8 mm. Head metallic bluishwhite; mouthparts including palpus brownish-yellow; antenna with scape, pedicel, first flagellomere and arista dark brown. Antenna with first flagellomere short-oval (as in Fig. 41 ).

Thorax dark brown to black with metallic bluish-white markings on lateral portion of presutural scutum, notopleuron, posterior portion of postsutural scutum, postalar callus, propleuron, mesopleuron, metapleuron, mediotergite and laterotergite; dark portion of presutural scutum silver-grey dusted. Scutum with 6 notopleural setae.

Legs brown with base of tibiae brownish-yellow; coxae metallic bluish-white dusted. Mid tibia with median anterodorsal seta absent, median dorsal seta present (as in Fig. 50 ); base of hind femur with long thin posteroventral seta (as in Fig. 54 ). Hind tarsomere 1 long, slightly narrower than apical width of hind tibia, length approximately 3X width.

Wing hyaline with cell sc faintly yellow. Halter dark brown.

Abdomen dark brown to black with lateral metallic bluish-white markings on tergites 1, 2 and 6; ventrolateral metallic bluish-white markings on tergites 3 and 4; sternites metallic bluish-white dusted, sternite 8 metallic bluishwhite.

Terminalia ( Fig. 56 ) with epandrium metallic bluish-white; surstylus and hypandrium brown; cercus brownishyellow. Epandrium with short tooth-like ventral lobe, pointed at apex; apical process elongate, pointed at apex. Surstylus broadly lamellate with narrow ventral process; dorsal lobe broad with rounded apex; ventral process moderately long, slightly curved dorsally. Hypandrium with elongate slender apical process; process trifid, with 2 moderately long narrow apical projections and short narrow basoventral lobe. Postgonite very long and narrow, tapered towards apex. Phallus sharply hooked at apex. Cercus short.

Female ( Figs 25 , 33 ). Body length 3.0– 3.2 mm; wing length 3.0– 3.3 mm. Head metallic bluish-white with dorsolateral portion of occiput bordering vertex reddish-brown; mouthparts brownish-yellow with palpus pale yellow; antenna with scape, pedicel, first flagellomere and arista brown to dark brown. Antenna with first flagellomere short-oval (as in Fig. 43 ).

Thorax brown and silver-grey dusted, with metallic bluish-white markings on postpronotal lobe, lateral portion of presutural scutum, notopleuron, posterior portion of postsutural scutum, postalar callus, propleuron, mesopleuron, metapleuron, mediotergite and laterotergite; scutellum dark brown to black. Scutum with 2 presutural intra-alar setae.

Legs brown with trochanters, base and apex of femora, and base of tibiae brownish-yellow; coxae metallic bluish-white dusted. Mid tibia with median dorsal seta absent.

Wing hyaline. Halter pale orange.

Abdomen dark brown to black with tergites 1 and 2 entirely pale orange and silver-white dusted; tergite 4 metallic bluish-white, interrupted by median dorsal dark band; tergites 6 and 7 entirely metallic bluish-white; sternites pale orange to light brown.

Terminalia with segment 8 metallic bluish-white; epiproct, hypoproct and cercus metallic bluish-white.

Type material. HOLOTYPE, ♂ labelled: “ USA: NEW MEXICO / McKinleyCo. 4mi./ S. Fort Wingate/ 8000’ 9-VII-1966 / P.H.Arnaud, Jr.; “ PAUL H. ARNAUD, JR./ COLLECTION/ Gift to California/ Academy of Sciences/ SanFrancisco, CALIF.; “ HOLOTYPE ♂/ Callomyia arnaudi / H.J. Cumming [red label] [dissected] ( CAS). PARATYPES: USA: NEW MEXICO: same data as holotype (1 ♀, CAS); same data as holotype except 10.vii.1966 (1 ♀, CAS); Sandoval County, 3.5 km NW La Cueva Santa Fe National Forest, Barley Cyn., 0.5 km off For. Rte. 144, 3553’N,10640’W, 2590 m, MT#15, 23–24.vii.1995, S.D. Gaimari (1 ♂, CNC).

Geographical distribution and seasonal occurrence ( Fig. 71 ). Callomyia arnaudi is only known from the type series collected in July from McKinley County and Sandoval County in New Mexico.

Etymology. This species is named after Dr. Paul. H. Arnaud Jr. of the California Academy of Sciences, who collected most of the type specimens.

Remarks. Callomyia arnaudi is closely related to the Nearctic species C. gilloglyorum and the Palaearctic species C. dives and C. saibhira Chandler , as shown in the strict consensus tree ( Fig. 79 ). The male terminalia of C. arnaudi are most similar to the terminalia of C. saibhira (comparison based on description and figures of C. saibhira in Chandler (2001, figs 238−240) and Tkoč & Roháček (2014, fig. 10)). However, the thoracic and abdominal colour patterns and shape of the hypandrial process differ between these two species.

Figures

FIGURE 71. Known distribution of C. arnaudi, C. bertae, and C. browni.

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 4 − 8. Callomyia males, lateral view. 4. C. argentea. 5. C. arnaudi (abdomen removed). 6. C. arnaudi abdomen in glycerin (coloured markings more metallic bluish-white than depicted). 7. C. browni. 8. C. bertae.

FIGURES 15 − 18. Callomyia males, dorsal view. 15. C. argentea. 16. C. arnaudi (abdomen removed). 17. C. bertae. 18. C. browni.

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 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 55 − 58. Callomyia male terminalia, lateral view. 55. C. argentea. 56. C. arnaudi. 57. C. bertae. 58. C. browni. Abbreviations: ap prj—apical projection; bv lb—basoventral lobe; cerc—cercus; d lb—dorsal lobe; d o csp—dorsal outer cusp; d prj—dorsal projection; epand—epandrium; epand ap proc—epandrial apical process; epand v lb—epandrial ventral lobe; hypd—hypandrium; hypd proc—hypandrial process; i proc—inner process; o proc—outer process; pgt—postgonite; phphallus; sur—surstylus; v i csp—ventral inner cusp; v prj—ventral projection; v proc—ventral process. 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).

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 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.