Lasiopogon drabicolum Cole

Mcknight, Tristan A. & Cannings, Robert A., 2020, Molecular phylogeny of the genus Lasiopogon (Diptera: Asilidae) and a taxonomic revision of the bivittatus section, Zootaxa 4835 (1), pp. 1-115 : 54-57

Lasiopogon drabicolum Cole

Lasiopogon drabicolum Cole, 1916: 65 .

Lasiopogon drabicola Cole ; Melander 1923: 137. Unnecessary emendation.

Diagnosis. ( Fig. 31 ) A small to medium dusty grey species from southern and central California; mystax variable but usually partly to completely white; setae on scape and pedicel at least partly white; scutal macrosetae black, finer setae white at least medially; scutum tomentum grey to brown with dorsocentral and acrostichal stripes indistinct; tergites with faint patches of brown tomentum basally, but mostly greyish white; lateral setae on tergites white. Male terminalia cuticle reddish to dark brown with sparse setae; epandrium in dorsal view appears circular, evenly rounded from base to apex; gonostylus in lateral view flattened, longer than tall; phallus with dorsal carina flat, extended apically equidistant to gonopore like a rounded porpoise fin. Ovipositor dark brown/black; acanthophorite spines black.

Redescription. Body length ♂ 6.9–7.7mm; ♀ 8.1–9.2mm. Head. HW ♂ 1.62–1.78mm; ♀ 1.84–2.14mm. FW ♂ 0.32–0.37mm; ♀ 0.38–0.46mm. VW ♂ 0.64–0.68mm; ♀ 0.68–0.83mm. VW/HW = ♂ 0.36–0.40; ♀ 0.35–0.42. FW/VW = ♂ 0.50–0.54; ♀ 0.49–0.56. VD/VW = ♂ 0.12–0.19; ♀ 0.12–0.17. GH/GL = ♂ 0.36–0.46; ♀ 0.37–0.48. Face grey, vertex brown-grey; occiput grey. Ventral setae (on beard, labium, palps) white; occipital setae black; orbital and ocellar setae usually black, rarely white; mystax and frontal setae usually predominately white, but variable from completely white to mostly black with some ventral white setae. Occipital macrosetae relatively straight, longest (to 0.6mm) and most curved posterior corners of vertex; frontal and orbital setae relatively short, reaching base of postpedicel; ocellar setae also relatively short. Antennae. Dark brown, with thin grey tomentum. Setae mostly white, at most 2 brown macrosetae dorsally and 1 ventrally on pedicel; no setae on postpedicel. Postpedicel moderately long, dorsal and ventral margins straight; stylus moderately long. WPP/LPP = ♂ 0.26–0.33; ♀ 0.33–0.38. LAS/LPP ♂ 0.54–0.70; ♀ 0.56–0.72. Thorax. Prothorax grey, with white setae; postpronotal lobes grey, the lateral angle light chestnut, setae white. Scutum tomentum brown to grey; dorsocentral and acrostichal stripes slightly darker but indistinct. Fine notal setae usually white, sometimes black except anteromedially; macrosetae always black. Dorsocentral and lateral macrosetae well developed: anterior dorsocentrals 3–5 (to 0.8mm); posteriors 3–5; postalars 2, with 2–3 fine setae; supra-alars 2–3; presuturals 2–3; posthumerals 0–1. Scutellar tomentum greybrown; apical macrosetae black, 4–9 on each half; shorter setae pointing straight up white, about 60% the length of apical macrosetae. Pleural tomentum greyish brown. Katatergite setae black, 6–8, with a few shorter white setae, sometimes 1–2 white long macrosetae; katepisternal setae wispy, white; anepisternal setae 3–4, black (to 0.5mm), with short white setae along dorsal margin and a few in posteroventral corner; anepimeron with 2–3 short fine white setae. Legs. Cuticle dark brown/ black, covered in grey tomentum except at femur joints. No coxal peg. Coxae with white setae. Fine setae of femur and tibia white, on tarsi black; Macrosetae of femur and tibia white basoventrally, black dorsoapically; black (rarely white) on tarsi. Ventral setae on femur as long as or shorter than femur width; dorsolateral macrosetae on profemur 5–11, with many finer setae; on mesofemur 3–5; on metafemur 7–12. Protibia with ventral macrosetae 2–3 times longer than tibial width; faint patch of short yellow setae on apical half of protibial and brown setae on metatibia. Claws chestnut over basal 60%, apically black. Wings. Veins brown; membrane hyaline but brown when viewed obliquely. DCI = 0.30–0.47. Halter knob cream, without spot, stem light brown.

Abdomen. Tergite cuticle dark brown/black. Apical bands of grey tomentum frequently weakly extend anteriorly along midline to divide basal brown tomentum into two lateral spots, but overall pattern weakly apparent and occasionally replaced by straight bands or totally grey (tergite 1 entirely covered in grey tomentum); lateral margin of tergites broadly grey. Tergite 1 with 0–4 brown and 2–7 white lateral macrosetae; lateral setae on tergites white, as long as halter on tergites 1–3, as long as scape + pedicel on tergites 4–7 in male, as long as scape only in female; dorsal setulae very fine, white or pale brown in male; black in female. Sternite tomentum grey, setae white. Male genitalia. Epandrium and hypandrium/gonocoxite complex cuticle red/dark brown, thin grey tomentum on epandrium, hypandrium mostly bare; setae mostly black (a few white), moderately long and erect but sparse; setal brush dark brown. Epandrium elongate, in lateral view the width about 50% the length, widest in basal third, dorsal and ventral margins gently sinuate; apex rounded into strong ventral subapical tooth. In dorsal view, epandrium appears circular, evenly rounded from base to apex; medial margins moderately curved, curvature starts about 39% from base; basal sclerite prominent. Phallus paramere sheath dorsally 55% the length of phallus; paramere sheath without ventral ornamentation; dorsal carina flat, extended apically equal to gonopore like a rounded porpoise fin, leaving a broad gap between apices. Ejaculatory apodeme in lateral view strongly bent dorsally in basal quarter, with broad dorsal carina. Subepandrial sclerite with triangular central unsclerotized area in basal 71%; spines parallel-sided, blunt, sparsely but evenly distributed.

Female genitalia. Undissected: Tergite 8 cuticle dark brown/black; sternite 8 dark brown/black basally, pale red-brown apically and at bases of hypogynial valves. Setae on segment 8 fine, white; cerci with white setae; a few short white setae on lateral lobes; acanthophorite spines black.

Variation. Mystax, frontal, orbital, and antennal setal color vary greatly from all white to mostly black in this species, but this observed variation does not follow a geographic cline and frequently occurs within a single population.

Type Material. HOLOTYPE (examined) ♂ labelled: “[rectangular beige label] Redlands,/ 1913 Cal.”; “[rectangular beige label] FRCole/ Coll”; “[rectangular beige label] Lasiopogon / drabicola/ Cole”; “[rectangular red label] Type No./ 20183/ U.S. N.M.”; “[rectangular white label] USNMENT00972437”. USNM.

PARATYPE (1 specimen examined): U.S.A.: CALIFORNIA: Riverside Co., La Quinta [33.643 -116.319], 14.iii.?, col. F.R. Cole (1♀ USNM, USNMENT01100210 [allotype]) .

Other Material Examined (273 specimens). [no loc], D. Martin (1♂ FSCA) ; U.S.A.: CALIFORNIA: [county uncertain] Santa Ana Canyon , 11.iii.1934, M.W. Stone (1♀ CAS) , Santa Ana Canyon , 21.iii.1934, M.W. Stone (1♂ 1♀ CAS) ; Los Angeles Co., Artesia [33.865 -118.103], 10.ii.1935, M.W. Stone (1♂ BEZA, 5♂ 4♀ CAS, 1♂ ESUW), 27.iii.1934, M.W. Stone (1♀ BEZA, 13♂ 3♀ CAS, 1♀ ESUW, 1♂ FISH, 2♂ 2♀ USNM, USNMENT1100212–USNMENT1100215) ; Burbank [34.171 -118.309], 23.iii.1933, C.H. Hicks (1♂ 1♀ WSUC) ; El Monte [34.066 -118.004], 18.iii.1933, M.W. Stone (1♂ 2♀ CAS) , [K.] Sloop & [M.W.] Stone (1♂ CAS) , 31.iii.1933, [K.] Sloop & [M.W.] Stone (5♂ CAS, 1♂ 1♀ MCZ), 2.iii.1934, M.W. Stone (4♂ CAS, 1♂ FISH, 1♂ OSUC, OSUC 194420 , 1♂ RBCM, 1♂ UCRC, UCRC ENT 449926 ), 17.ii.1935, M.W. Stone (16♂ 5♀ CAS, 1♀ RBCM, 2♀ UCRC, UCRC ENT 449924 – UCRC ENT 449925 ) ; El Monte, San Gabriel River wash [34.066 -118.004], 2.iii.1934, M.W. Stone (8♂ 8♀ CAS, 1♂ 1♀ CNC, 1♀ OSUC, OSUC 194423 , 1♂ 1♀ RBCM, 2♂ 2♀ USNM, USNMENT1100206 – USNMENT1100209 ) ; Napa Co., Monticello [38.578 -122.207], 16.iv.1952, E.I. Schlinger (1♂ CAS) , R.M. Bohart (1♀ CAS) ; Samuel Springs [38.605 -122.311], 24.iii.1956, R.C. Bechtel (1♂ 1♀ [1 pr in cop] RBCM) ; Orange Co., [no loc], 3.iii.1957, R. Swigart (1♂ CAS) ; Anaheim [33.835 -117.863], 5.iii.1937, J. Wilcox (3♂ 5♀ CAS) , M.W. Stone (1♂ CAS) ; Riverside Co., Mira Loma [33.973 -117.511], 26.iii.1957, J. Wilcox (1♀ CAS) ; Riverside [33.989 -117.393], 17.iii.1935, A.L. Melander (1♂ 4♀ USNM, USNMENT1100216 –USNMENT1100220), 23.iii.1941, Timberlake (2♂ 5♀ UCRC, UCRC ENT 449928 – UCRC ENT 449931 , UCRC ENT 449937 – UCRC ENT 449939 ), 6.iv.1941, Timberlake (4♂ 2♀ UCRC, UCRC ENT 449932 – UCRC ENT 449936 , UCRC ENT 449940 ) ; Riverside, Santa Ana River [33.969 -117.426], 24.iii.1942 (2♂ 1♀ FSCA) , C.H. Martin (3♂ 6♀ FSCA) , D. Martin (4♂ FSCA, 1♀ RBCM), 12.iii.1944 (1♀ FSCA, 1♂ RBCM), C.H. Martin (2♂ 5♀ FSCA) , D. Martin (1♀ FSCA) , 11.iv.1964, M.E. Irwin (1♂ UCRC, UCRC ENT 449944 ), 24.iii.1969, F.G. Andrews (2♂ 1♀ UCRC, UCRC ENT 449941 – UCRC ENT 449943 ) ; Santa Ana River at Mt. Rubidoux [33.98948 -117.39281], 4.iii.2013, T.A. McKnight (1♂ 2♀ [1 pr in cop] RBCM, 3♂ 2♀ [1 pr in cop] TAM, 2♂ 2♀ [3 EtOH] UMMZ) ; San Bernardino Co., South Fork [34.169 -116.826], 12.vii.1942, C.H. Martin (2♂ 2♀ FSCA) ; San Diego Co., Warner Springs [33.281 -116.654], 23.v.1953, R. Mackie (1♀ SDMC, SDNHM014871 ) ; San Luis Obispo Co., Paso Robles, Salinas River E side [35.642 -120.683], 17.iv.1990, D.W. Webb, M.E. Irwin (1♂ 1♀ INHS) ; San Simeon Creek , rapids above bridge ~ 4 mi E of San Simeon, 35.60795 -121.09053, 10.v.2012, T.A. McKnight (1♀ [1 EtOH] UMMZ) ; Simmler , 10 mi W [35.387 -120.151], 5.v.1962, R.W. Thorp (2♀ FISH) ; Ventura Co., Casitas Springs [34.372 -119.309], 20.iv.1979, R.P. Meyer (2♀ BEZA) ; Moorpark [34.284 -118.856], 22.iv.1941, M.W. Stone (1♂ 3♀ CAS, 1♂ FISH) ; Ojai valley [34.439 -119.237], 6.iv.1941, J. Wilcox (1♀ CAS) ; Piru Creek, NE base Alamo Mtn [34.703 -118.937], 3.v.1959, J. Powell (1♀ FISH) ; Santa Ana Valley , 6.iv.1941, J. Wilcox (13♂ 9♀ CAS, 1♀ FISH, 1♂ RBCM) ; Sespe River [34.492 -118.945], 6.v.1942, M.W. Stone (3♂ 3♀ CAS) ; Yolo Co., Davis [38.5177 -121.7696], 17.iv.1952, R.C. Bechtel (1♂ 1♀ CAS) , 2.iv.1952,A.T. McClay (2♂ CAS) , E.I. Schlinger (2♂ 1♀ CAS, 1♀ RBCM), 22.iv.1959, J.R. Powers (1♀ FISH) , 27.iv.1951, R.C. Bechtel (1♂ 1♀ FISH) , 6.iv.1951, R.C. Bechtel (2♂ CAS, 1♂ FISH, 1♂ 1♀ [1 pr in cop] FSCA), 7.iv.1956, W.H. Lange (1♂ 1♀ [1 pr in cop] CAS, 1♂ 1♀ ESUW, 2♂ 3♀ FSCA), 7.v.1961, V.L. Vesterby (1♂ BEZA) , 8.iii.1960, F.D. Parker (1♀ CAS) ; Putah Canyon [38.514 - 122.072], 21.iv.1949, H.E. Cott (2♀ LACM, LACM ENT 334039 – LACM ENT 334040 ), 15.iv.1952, A.T. McClay (1♀ FISH) , S. Miyagawa (1♂ FSCA) , 2.iv.1954, R.C. Bechtel (1♂ CAS, 1♂ 1♀ [1 pr in cop] FSCA, 1♂ RBCM), 20.iii.1951, A.T. McClay (1♂ CAS) , R.M. Bohart (1♀ CAS, 1♂ FSCA), 24.iii.1951, R.C. Bechtel (1♂ FSCA) , 25.iii.1951, E.J. Taylor (1♂ RBCM) .

Taxonomic Notes. Cole’s original description used the spelling “drabicolum”, but most subsequent authorsincluding Cole in his later publications—have used the corrected Latinization “drabicola” undoubtedly because that is the actual masculine form for names ending in ‘-cola’. However, this change does not appear to be compliant with the modern ICZN Code. The first published usage of “drabicola” was by Melander (1923), but the first usage that was a demonstrably intentional change in the sense of article 33.2.1 was by Cole & Wilcox (1938), who cited both spellings. Unfortunately, incorrect Latinization does not count as an “inadvertent error” that must be corrected according to the Code (article 32.5.1), so this emendation is unjustified (article 33.2.3). Furthermore, we do not judge that “drabicola” meets the prevailing usage standard to override this rule as in article 33.2.3.1. Most notably, the high-profile monograph “ Robber Flies of the World” ( Hull 1962) used “drabicolum” and is still a routinely consulted reference, and we have encountered several museum collections using this spelling. The Code’s definition of “prevailing usage” is vague (and only the glossary definition applies for questions of spelling), but “drabicola” would not meet the standard suggested for evaluating prevailing usage for synonyms and homonyms (Code Introduction clause 11). Thus, our recommedation is that the name should revert to the original spelling “drabicolum”.

Several cryptic new species in California have historically been identified as this species, including L. apoecus sp. nov., L. esau sp. nov., and L. nelsoni sp. nov.

Etymology. No explanation given in the original description, but the description mentions that the flies “were collected on wild flowers” and the name was evidently derived from the Latin “draba” = mustard plant, “cola” = dweller of.

Distribution. ( Fig. 37 ) Nearctic, U.S.A., southern and central California. Type locality: U.S.A., California, San Bernardino Co., Redlands.

Phylogenetic Relationships. Member of the bivittatus section, drabicolum group. Likely closely related to L. esau and L. nelsoni .

Natural History. Habitat: mountain and lowland river banks. Despite Cole’s remarks about collecting this species on flowers, we have only ever encountered it perching on patches of bare sand interspersed with vegetation or rocks along riverbanks <1–20 m from the water ( Fig. 21 ). Specimens recorded between 10 February to 12 July, most in March and April. Two males and two females with prey: 3 small Scarabaeidae ( Coleoptera c.f. Aphodiinae , see Fig. 4 ) and Muscidae c.f. Phaonia Robineau-Desvoidy (Diptera) . Broadly sympatric and occasionally found flying simultaneously with L. nelsoni , but perching habit may help distinguish these taxa, as L. drabicolum tends to perch on sand and L. nelsoni on rocks.

Figures

FIGURE 31. Matrix key of Lasiopogon morphology for species revised in this publication, indicating details of tergite tomentum, major setation, and dissected male genitalia. Taxa are grouped on pages with closely related and visually similar species. (31) L. albidus, L. arenicola, L. asilomar sp. nov.

FIGURES 37–40. Distribution maps of georeferenced records for Lasiopogon species revised in this publication, part 1 of 2. Each map corresponds to one page of the morphology tabular key.

FIGURES 14–21. Representative habitats of inland sand-perching Lasiopogon species collected for this revision. (14) Washington: Asotin Co., Snake River, sandy bank 4 mi S of Asotin jct Hwy 129, 21.iv.2014 (L. ripicola). (15) Washington: Thurston Co., Tumwater, Deschutes River @ Pioneer Park, 15.v.2015 (L. puyallupi stat. nov.). (16) Oregon: Linn Co., Crabtree Creek @ Hwy 226 bridge 8 mi N of Lebanon, 19.v.2012 (L. willametti). (17) Washington: Franklin Co., Juniper Dunes Wilderness, N entrance, 18 mi NE of Pasco, 20.iv.2014 (L. albidus). (18) California: Marin Co., San Antonio Creek, San Antonio Rd 4.5 mi S of Petaluma, 15.iii.2014 (L. zonatus, L. esau sp. nov.). (19) California: Riverside Co., Little San Gorgonio Creek @ Potrero blvd bridge, 2 mi NW of Beaumont, 9.iii.2014 (L. wilcoxi sp. nov.). (20) New Mexico: Grant Co., Gila River below Forks campsite, 6.v.2015 (L. karli sp. nov.). (21) California: Riverside Co., Santa Ana River at Mt. Rubidoux, 4.iii.2013 (L. drabicolum).

FIGURES 2–5. Lasiopogon ethology. Mating pair (2) and ovipositing (3) Lasiopogon littoris at Surf Beach, Santa Barbara Co., California, U.S.A., 28.iii.2015. Photos by Alice Abela; (4) Lasiopogon drabicolum with prey (Scarabaeidae: Aphodiinae) at Santa Ana River by Mt. Rubidoux, Riverside Co., California, U.S.A., 4.iii.2013, photo by T.A. McKnight; (5) Lasiopogon littoris with prey (Acari) at Oso Flaco Lake, San Luis Obispo Co., California, U.S.A., 12.iv.2015. Photo by Aaron Schusteff.