Romaleosyrphus arctophiloides (Giglio-Tos, 1892) Moran & Skevington, 2021

Moran, Kevin M. & Skevington, Jeffrey H., 2021, Taxonomic revision of Romaleosyrphus Bigot (Diptera, Syrphidae), including descriptions of seven new species, ZooKeys 1075, pp. 1-32 : 1

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Romaleosyrphus arctophiloides (Giglio-Tos, 1892)

comb. nov.

Romaleosyrphus arctophiloides (Giglio-Tos, 1892) comb. nov.

Figures 4A View Figure 4 , 6A View Figure 6 , 8A View Figure 8 , 9A View Figure 9 , 10A View Figure 10 , 11A View Figure 11

Crioprora arctophiloides Giglio-Tos, 1892: 7. - Giglio-Tos (1893): 25. - Aldrich (1905): 401. Type locality: Mexico, Angang[ueo] [MRSN]

Penthesilea arctophiloides Kertész, 1910: 286.

Criorhina tapeta Fluke, 1939: 369. -Thompson (1976): 119. Type locality: Mexico City, 10,000 ft. [AMNH]

Criorhina arctophiloides Thompson, 1976: 118.

Material examined.

Mexico. Durango: 14 miles Southwest of El Salto, 23.702772, -105.564053, 2438m,, W.R.M. Mason, CNC_ Diptera 142464 (1♂, CNC); Mexico City, D.F.: San Pedro Atocpan, 19.204792, -99.048853, 2600m, 16.ix.1947, C. Bolivar, CNC_ Diptera 142465 (1♂, CNC);1910, USNM_ENT1071372 (1♂, USNM) GoogleMaps ; Mexico: Edo. de Mexico, km. 73rd to Popocatépetel, 19.075366, -98.65902, 3352m, 15.vii.1961, D.H. Janzen, EMEC354664 (1♀, EMEC); Nevado Toluca, 19.110036, -99.753425, 3200m, 11.vii.1951, H.E. Evans, Jeff_Skevington_Specimen52560 (1♂, CNC); 19.110035, -99.753423, 3444m, 11.vii.1951, P.D. Hurd, EMEC354662 (1♂, EMEC); West Slope, Cortez Pass, 19.08569, -98.648296, 2743m, 13.vii.1954, R.R. Dreisbach, KMM0919 (1♂, WIRC); 19.08569, -98.648296; 19.085692, -98.648297, 2743m;~ 13.vii.1954, CNC_Diptera142466;CNC_Diptera142467 (1♂, 1♀, CNC); Mexico City, 19.42250, -99.14389, 10000ft, vii.1936 (1♂ HT AMNH); Morelos: #17 Lagunas de Zempoala Nat. Park , 19.04828, -99.312179, 2865m, 23.viii.1969, G.W. Byers, KMM0920 (1♂, SEMC); Cuernavaca, 18.924211, -99.221567, 2133m, 29.vii.1961, R. & K. Dreisbach, J_ Skevington _ Specimen 50177 (1♀, ANSP) GoogleMaps .

Differential diagnosis.

Scutellum only partly yellow pilose, black pilose anteriorly and medially. Tergite II-III extensively rufous to yellow pilose. Tergite IV dominantly black pilose, but sometimes with rufous or yellow pile medially or posteriorly. Hind trochanter not tuberculate in male.


MALE. Body length: 13.1-14.8 mm. Wing length: 8.6-9.4 mm.

Head. Face shape as in Fig. 10A View Figure 10 ; face silver or gold pruinose; gena black pilose posteriorly; anterior tentorial pit variable pilose: yellow or black; frons broad, ca. as long as broad at antenna, 2/3 as broad at vertex as at antenna, black pilose and silver-gold pruinose; vertex triangular, longer than broad, black pilose and brown pruinose; postocular setae black; occipital setae variable: yellow or black; antenna reddish orange.

Thorax. Matte black; postpronotum variable pilose: black or mixed black and yellow; scutum black pilose; scutellum yellow pilose, except black pilose anteromedially; postalar callus variable pilose: yellow, black or mixed black and yellow; proepimeron black pilose; posterior anepisternum yellow pilose; katepisternum yellow pilose posteriorly with broadly separated patches; metasternum variable pilose: black, yellow or mixed black and yellow; anepimeron with anterior portion yellow pilose; lower calypter with long black pile.

Legs. Coxae black; femora black except extreme apex of femora; remainder of legs reddish; hind trochanter rounded, not tuberculate as in Fig. 8A View Figure 8 ; fore and mid-coxae black pilose; hind coxa mixed black and yellow pilose; fore femur black pilose, except occasionally with small mix of yellow pile basally; mid femur fully black pilose or with stretch of yellow pile on posterior side; hind femur black pilose; tibiae and tarsi black pilose; hind tibia as in Fig. 9A View Figure 9 .

Wing. Microtrichia absent from following areas: broad anterior margin of cell cua.

Abdomen. Tergites shiny to subshiny black; tergite I with scattered, yellow pile medially, except with short black pile in lateral corners; tergite II with dense yellow pile; tergite III with dense pile which is yellow anteromedially, rufous from anterolateral corners to posteromedial margin and black in posterolateral corners; tergite IV variable, dominantly black pilose, but sometimes with rufous or yellow pile medially or posteriorly; grey pruinosity as follows: tergite I pruinose posteriorly, all of tergite II, tergite III except in posterolateral corners; sternites I-III yellow pilose and not pruinose; sternite IV variable: black or rufous pilose or some mix of the two; pile of postabdomen rufous or yellow.

Male genitalia. (Fig. 11A View Figure 11 ) Cercus yellowish brown, broader at apex, covered with long yellow pile; surstylus brown, ca. 2 × as long as broad, broadened basally with apical third tapering, directed ventrally and with an acute apex, ventral margin concave, undulated; pile on dorsal surface of surstylus, increasing in length posteriorly; minute spines on ventral surface and apical 3/4th of lateral inner and outer surface.

FEMALE. As male, except for usual sexual dimorphism; microtrichia on wing absent in following areas: broad anterior margin of cell cua, medial area of cell bm, anterior margin in cell dm, small region anteriorly in cell m4 near cross-vein m-cu.




Trans-Mexican Volcanic Belt pine-oak forests ecoregion.


Romaleosyrphus arctophiloides is the only known member of Romaleosyrphus in which the hind trochanter is not tuberculate in the male. Although males are not known for Romaleosyrphus argosi sp. nov., R. drysus sp. nov. and R. woodi sp. nov., males of their closest relative in the COI gene tree, R. nephelaeus sp. nov., possess a tuberculate hind trochanter. It is therefore expected that males of these three species also have a tuberculate hind trochanter.

We suspect that a single specimen “CNC_Diptera142464” collected in the Sierra Madre Occidental may represent a distinct species from specimens collected in the Trans-Mexican Volcanic Belt pine-oak forests. Although no genital or discrete morphological differences could be found, the legs of this specimens are fully black pilose while those of all the others have a streak of yellow pile at the base of the fore and mid femora. Unfortunately, while a barcode was obtained for this specimen, no barcode sequences were obtained from specimens from specimens collected in the Trans-Mexican Volcanic Belt pine-oak forests.














Romaleosyrphus arctophiloides (Giglio-Tos, 1892)

Moran, Kevin M. & Skevington, Jeffrey H. 2021

Crioprora arctophiloides

Moran & Skevington 2021

Penthesilea arctophiloides

Moran & Skevington 2021

Criorhina tapeta

Moran & Skevington 2021

Criorhina arctophiloides

Moran & Skevington 2021