Lasiopogon bivittatus Loew

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 : 45-47

Lasiopogon bivittatus Loew

Lasiopogon bivittatus Loew, 1866: 93 .

Daulopogon bivittatus (Loew) ; Osten Sacken, 1877: 310. Genus name was an unnecessary replacement for Lasiopogon .

Diagnosis. ( Fig. 35 ) A medium-sized dark species from coastal dunes of central and northern California; mystax black, thoracic tomentum grey with dark dorsocentral stripes, thoracic setae mostly black except light setae on postpronotal lobe in male; femur basally with white setae and thin grey tomentum, apical 40% black haired and with cuticle polished; tergites with dark brown/black cuticle subshining basally, grey tomentum bands cover apical 30% and lateral margins; lateral macrosetae on tergite 1 mostly pale, 3–4 black. Epandrium polished dark brown/black, in dorsal view narrow, coming to sharp apex, with moderately concave medial margins, apex straight or gently concave into strong ventral subapical tooth; ovipositor black with light setae.

Redescription. Body length ♂ 8.7–10.5mm; ♀ 9.6–11.8mm. Head. HW ♂ 2.02–2.45mm; ♀ 2.25–2.65mm. FW ♂ 0.48–0.59mm; ♀ 0.57–0.66mm. VW ♂ 0.83–0.98mm; ♀ 0.97–1.10mm. VW/HW = ♂ 0.39–0.42; ♀ 0.42– 0.43. FW/VW = ♂ 0.58–0.60; ♀ 0.59–0.60. VD/VW = ♂ 0.11; ♀ 0.10–0.14. GH/GL = ♂ 0.32–0.53; ♀ 0.40–0.52. Face with silver-grey tomentum, vertex sparse grey under setae patches, subshining otherwise. Beard and labial setae white, sometimes tinged yellowish; mystax and all other setae black. Occipital macrosetae relatively fine and long; those behind the dorsomedial angle of the eye the longest (to 0.7mm), moderately curved anterolaterally; lateral and ventral macrosetae shorter, straighter. Frontal setae fine, long, and erect, reach midpoint of postpedicel; orbital setae also fine and long, slanting over eye margin. Antennae. Black, dark grey at base of postpedicel. Setae black; 0–1 setae on postpedicel. Postpedicel long, spindle shaped, widest at midpoint. WPP/LPP = ♂ 0.23–0.26; ♀ 0.22–0.28. LAS/LPP ♂ 0.68–0.77; ♀ 0.66–0.77. Thorax. Prothorax grey, with white setae; postpronotal lobes grey, the lateral angle yellowish red, setae mostly white in male, a few brownish setae on outside edge. In female, all setae on postpronotal lobes brown. Scutum tomentum thin, slate grey, sometimes with a brownish tinge especially around perimeter. Dorsocentral stripes dark brown, edged in yellow; acrostichal stripes absent. Notal and acrostichal setae black, widely spaced, long (up to 60% as long as dorsocentrals). Dorsocentral macrosetae fine, black (to 1.0mm), anteriors 4–5, can be hard to distinguish from surrounding setae, 3–4 posteriors. Postalars 2–3, with about 4 long surrounding setae; supra-alars 2–3 with a few short setae; presuturals 2–3; posthumerals 1. Scutellar tomentum grey/greyish brown; rim inflated, leaving a semi-circular line impressed inside the dorsal edge; apical macrosetae black, abundant (10+ on each side) and mixed with many other long setae. Setae on uppermost edge of rim short (half the length of other macrosetae), point straight up. Pleural tomentum grey to brownish grey. Katatergite macrosetae black, 8, with a few fine white setae about half as long; katepisternal setae fairly long, wavy, white; anepisternal setae 14+, mostly black (to 0.9mm) with a few white setae ventrally and a patch of short black setae along dorsal edge; anepimeron with 5 fine white setae. Legs. Base color dark brown/black, chestnut at femur-tibia joint and trochanters. Tomentum on coxae grey, on basal 60–70% of femur sparse grey, elsewhere shining black. No coxal peg. Coxae with long straw/white setae. Main macrosetae of legs black, setae on basal 60–70% of femur white, elsewhere black. Dorsolateral macrosetae on femur are numerous, long, fine, and are almost indistinguishable from the surrounding setae, at least on the profemur. Setae erect on outside face of femur, reclinate on inside face. At least 10+ dorsolateral macrosetae on profemur, mesofemur with 3–5, metafemur 8–13, colored as with the shorter setae. Longest ventral setae are longer than the width of the femur. Tibiae and tarsi have dark, strong macrosetae typically arranged; setae brown. Short dense macrosetae on inside of protibiae yellow. Protibia with longest macrosetae about 4 times longer than tibial width. Claws dark chestnut over basal 60%, black apically. Wings. Veins dark brown; membrane hyaline, very pale brown when viewed obliquely. DCI = 0.44–0.54. Halter yellow; knob without dark spot. Abdomen. Male. Tergite cuticle dark brown/black. Very thin brown tomentum on tergite bases, extensively lacking so the dark cuticle shines through, bands of grey tomentum cover apical 30% of each tergite in an even band (tergite 1 half covered) and extending ventrolaterally to cover lateral margins. Tergite 1 with 2–4 black and 4–6 white/yellow lateral macrosetae; lateral setae on tergites long, erect, white; on tergites 2–4 setae longer than F1, on tergites 1 and 5–7 as long as scape + pedicel. Dorsal setulae white/brownish white, relatively long. Sternite tomentum grey, setae white. Female. Tergite bases have thicker brown tomentum. More black macrosetae on side of tergite 1, usually 4–9. Male genitalia. Epandrium and hypandrium/gonocoxite complex cuticle polished dark brown/black, entirely devoid of tomentum; with dark brown/black setae, setal brush black. Epandrium elongate, slender, in lateral view the width 40% the length, with dorsal and ventral margins parallel; apex straight or gently concave from dorsoapical corner to sharp subapical ventral tooth. In dorsal view, epandrium moderately concave, tapered; basal sclerite weak. Phallus paramere sheath dorsally 35% the length of phallus; paramere sheath with sharp ventral subapical tooth; dorsal carina a flat fin curving away apically into shallow sharp point parallel to aedeagal tube, leaving a narrow gap between the apices. Ejaculatory apodeme in lateral view long, slender, straight to slightly bent in basal quarter, dorsal carina narrow basally, wider apically. Subepandrial sclerite U-shaped, central unsclerotized area shaped like a tall bottle over basal 90%; spines parallel-sided, blunt, densely and evenly distributed, apical spines moderately erect.

Female genitalia. Undissected: Setae white, erect. Tergite and sternite 8 cuticle dark brown/black; hypogynial valves long, black, with a few setae basally; cerci reddish brown with pale setae; acanthophorite spines black.

Type Material. LECTOTYPE (examined) ♂ labelled: “[rectangular white label with illegible handwritten symbol on back] Cala.”; “[rectangular beige label] Loew/ Coll.”; “[square red label] Type/ 12804”; “[handwritten rectangular beige label] bivittatus/ m.”; “[rectangular white label] Museum of/ Comparative/ Zoology”; “[rectangular white label] MCZ-ENT 00012804 ”; “[handwritten rectangular pink label] Should have a lectotype / label; will designate at/ a later date. RAC”. Our lectotype label “ LECTOTYPE / Lasiopogon ♂ / bivittatus Loew / des. T.A. McKnight 2017 [red, black-bordered label]” has been attached to this specimen. MCZ.

PARALECTOTYPE (examined): U.S.A.: CALIFORNIA: San Francisco Co., San Francisco [37.784 - 122.444], H. Edwards (1♂ MCZ) .

Other Material Examined (187 specimens). U.S.A.: CALIFORNIA: [no loc] (1♀ FISH) ; Marin Co., [no loc], v.1964, P.A. Gage (1♀ BEZA) ; Mill Valley [37.904 -122.534], 24.v.1926, M.C. Van Duzee (1♂ FISH) ; Pt. Reyes , 30.iii.1956, E.A. Kurtz (1♂ FSCA, 1♂ RBCM), J.C. Downey (1♂ ESUW, 1♂ FSCA), W.H. Lange (1♂ FISH, 1♂ FSCA), 31.iii.1956, A.M. Barnes (1♂ BPBM, 17♂ 2♀ EMEC, 3♂ RBCM), 7.iv.1956, A.M. Barnes (2♂ BEZA, 4♂ 1♀ [1 pr in cop] EMEC), 7.iv.1957, Menke, Strange (1♀ EMEC), 11.iv.1959, G.I. Stage (1♂ 2♀ EMEC), R.W. Thorp (2♂ 1♀ EMEC), 14.iv.1959, D. Burdick (1♂ 1♀ EMEC) ; Pt. Reyes beach, north [38.074 - 122.976], 13.iv.1976, E.M. Fisher (1♂ 1♀ CSUC, 10♂ 8♀ FISH, 1♂ LACM, LACM ENT 334018 ) ; Point Reyes beach streams S of N beach parking lot, 38.07444 -122.97589, 14.iii.2014, T.A. McKnight (1♂ TAM, 3♂ 1♀ [3 EtOH] UMMZ) ; Pt. Reyes lighthouse, 1 mi N [38.007 -123.007], 7.iv.1957, A.M. Barnes (7♂ 4♀ EMEC, 1♂ 1♀ RBCM), Pt. Reyes lighthouse, 2 mi N [38.018 -123.002], 7.iv.1956, A.M. Barnes (1♂ CAS) ; Stinson Beach [37.897 -122.642], 7.iv.1962, J. Doyen (1♂ EMEC) ; Monterey Co., Carmel [36.556 -121.931], 26.iii.1930, L.S. Slevin (1♂ EMEC) ; Little Sur Beach [36.332 -121.893], 17.v.1976, L. Bezark (1♂ BEZA) ; Marina , 3 km E, 36.71667 -121.79983, 6.iv.2011, M.E. Irwin (9♂ 1♀ UAIC) ; Marina, Coastal Sand Dune Association [36.697 -121.809], 10.v.1971, M.E. Irwin (1♂ 2♀ [1 pr in cop] UCRC, UCRC ENT 449914 – UCRC ENT 449915 ) ; Pacific Grove [36.633 -121.936], 1.iv.1904 (1♂ EMEC) , 15.iv.1965, B.A. McKinley (1♂ CAS) ; San Francisco Co., [no loc], 29.iii.1920, A.J. Basinger (2♂ 4♀ EMEC) , 2.v.1920, A.J. Basinger (1♂ EMEC) ; Baker Beach [37.793 -122.484], 18.iii.1977, J. Powell (3♂ 1♀ [1 pr in cop] EMEC) ; Fort Funston [37.717 -122.504], 16.iv.1960, G.I. Stage, R.R. Snelling (1♀ EMEC) , Fort Funston dunes by Battery Davis , 37.71862 -122.50398, 14.iii.2014, T.A. McKnight (1♀ RBCM, 1♂ 1♀ TAM, 1♂ [1 EtOH] UMMZ) ; Lake Merced [37.719 -122.489], 9.iv.1916, E.C. Van Dyke (1♂ EMEC, 1♂ OSUC, OSUC 194361 ) ; Lobos Creek [37.791 -122.485], 16.v.1960, J.F. Lawrence (1♀ EMEC) , 26.iii.1967, P.H. Arnaud, Jr. (3♂ CAS) ; Presidio [37.791 -122.485], 3.iv.1954, E.I. Schlinger (2♀ EMEC, 2♂ FSCA, 1♂ 1♀ FISH), J.C. Downey (1♀ EMEC) , W.H. Lange (2♂ FSCA) ; Presidio, open area back of US Marine Hospital [37.791 -122.485], 31.iii.1968, T.W. Davies (1♂ 1♀ CAS) ; San Francisco [37.784 -122.444], 28.iii.1876, Osten Sacken (1♂ 3♀ 1? [1 pr in cop] MCZ) , 19.iv.1908, E.C. Van Duzee (1? CAS) , 20.iii.1915, C.L. Fox (2♂ 2♀ EMEC) , 30.iii.1919, E.P. Van Duzee (1♀ MCZ) , 4.iv.1920, A.J. Basinger (2♂ 1♀ EMEC) , 22.v.1926, M.C. Van Duzee (1♂ FISH) , 25.v.1926, M.C. Van Duzee (1♂ CAS) , 3.iii.1957, D. Rentz (1♀ CAS) , 1.iii.1960, J.A. Goodwin (2♂ EMEC) , 18.iii.1960, G.I. Stage (1♀ CAS) , 9.v.1960, P.H. Arnaud, Jr. (1♀ CAS) , 28.iii.1961, D.C. Rentz (1♀ CAS) , 23.iii.1963, P.H. Arnaud, Jr. (4♂ 1♀ CAS, 1♀ RBCM), 24.iii.1968, H.B. Leech (1♀ CAS) ; San Francisco beach [37.763 -122.511], 13.iv.1958, A.D. Telford (2♂ FSCA) ; San Francisco, Quintara Street dunes [37.747 - 122.508], 7.iv.1961, R.L. Langston (1♀ FISH) ; San Francisco, Sunset sand dunes [37.743 -122.508], 1.iv.1960, G.I. State (1♂ USNM, USNMENT1100762 ) ; San Mateo Co., Greyhound Rock coast [37.0792 -122.2674], 22.v.1952, P.H. Arnaud, Jr. (1♂ CAS) ; Santa Cruz Co., Ano Nuevo State Beach [37.129 -122.336], 16.v.1976, L.S. & R.B. Kimsey (1♀ BEZA) ; Santa Cruz [36.964 -122.009], 5.iv.1961, R. Brown (2♂ CAS) ; Waddell Creek [37.097 - 122.279], 11.iii.1956, D.J. Burdick (1♂ EMEC) , Waddell Creek Stanford University lot 6068 sub 4, 20.iii.1930, F. Bianchi (1♂ LACM, LACM ENT 334078 ) ; Sonoma Co., Bodega Head, UC Davis Bodega Marine Lab , 38.31788 -123.06657, 10.v.1975, R.W. Thorp (1♀ BEZA) , 13.iii.2017, C.E. Herbert (4♂ 1♀ [1 pr in cop] UCDC, BME P0241407, BME P0241429 , BME P0241627 , BME P0241791 ), 14.iii.2017 , C.E. Herbert (1♂ [EtOH] UCDC), 15.iii.2017 , C.E. Herbert (1♂ 1♀ [2 EtOH] UCDC) .

Taxonomic Notes. Back’s (1909: 299) comment that “a single female in the Loew collection is probably the type” is incorrect as Loew’s original description indicates that the description is for a male and the specimens in the MCZ Loew collection are both male. Alexander (1969) noted that when the Loew collection was returned to America in 1876, type specimens had been isolated and given individual handwritten labels with only the species name; one specimen bears labels appropriate for this protocol. The other specimen from the Loew collection, evidently donated to him from the San Francisco lepidopterist Henry Edwards, has different labels. However, since the description does not list the number of specimens examined and localities in Loew’s Centuries (a series of publications each with one hundred new species descriptions written in Latin, e.g., Loew 1866) were typically not recorded more precisely than at the state level, we cannot preclude the possibility that Loew already had both specimens when he wrote the description. To avoid further ambiguity, we are herein designating the specimen traditionally treated as the type as a lectotype, and the Edwards fly as a paralectotype. See note under L. arenicola for the history of Daulopogon as a generic name.

In all previous publications, the species concept of L. bivittatus included L. canningsi sp. nov. and L. tumulicola sp. nov., which are closely related allospecies found on beaches to the north. We have chosen to split this complex because the specimens along this coastline sort into three discrete groups based primarily on epandrium shape and mitochondrial genome. Of the three, L. bivittatus has the most divergent genome (COI p-distance between L. bivittatus and the other two species is 4.9–7.4%) and specimens can be further distinguished by their broader stripes of apical grey tomentum on the tergites.

Etymology. No explanation given in the original description, but evidently from the Latin bi = two, vitta = ribbon, stripe; thus, two-striped, a reference to the dark dorsocentral stripes on the mesonotum.

Distribution ( Fig. 41 ) Nearctic; coastal dunes in central California from Bodega Head to Monterey, but with most specimens from the San Francisco bay area. As the first dark-colored species described from western North America, several erroneous records exist in the literature: Coquillett specimens from Los Angeles County ( Back 1909, Cole & Wilcox 1938) have been verified to actually be L. zonatus ; Cole specimens from Mt. Hood, Oregon ( Cole & Lovett 1921) are actually L. ripicola Melander ; and other records from Mt. Hood ( Back 1909, Cole & Wilcox 1938) and Wyoming ( Lavigne & Dennis 2019, Metz & Nonidez 1924) are undoubtedly also misidentifications (likely L. aldrichii with shiny black genitalia) although the voucher specimens have not been located for verification.

Type locality: California (no other data). Many species described in Loew’s Centuries (see above for explanation, e.g., Loew 1866) were based on specimens collected in California by Alexander Agassiz, but the description and labels on the type specimens for L. bivittatus lack the usual annotations for Agassiz and leave us at a dead end for tracing the provenance of these specimens (based on the discussion in Osten Sacken 1904). However, given the known current range for this species and the fact that most insect collectors in antebellum California stopped in San Francisco, we can assume that the specimen was collected from those general environs.

Phylogenetic Relationships. Basal member of a new bivittatus group, which is itself basal to the rest of the bivittatus section (equivalent to the bivittatus group sensu Cannings 2002).

Natural History. Habitat: Coastal beaches and dunes. Found perching on bare sand near sparse vegetation in back dune field, also on logs across streams running through beach (similar to Figs. 9–10 ). Flight dates range from 1 March to 25 May, most in late March to mid-April. Three females with prey: 1 Bibio c.f. necotus Hardy ( Diptera : Bibionidae ), 2 Muscidae c.f. Hydrotaea Robineau-Desvoidy (Diptera) .

One specimen has an associated pupal case; this will be described in a forthcoming work. The cytology observations of Metz & Nonidez (1924) and habitat description of Lavigne & Dennis (2019) are misattributed to this species; it does not occur in Wyoming.

Figures

FIGURE 35. 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. (35) L. bitumineus sp. nov., L. bivittatus, L. canningsi sp. nov., L. littoris, L. tumulicola sp. nov.

FIGURES 41–42. Distribution maps of georeferenced records for Lasiopogon species revised in this publication, part 2 of 2. Each map corresponds to one page of the morphology tabular key.

FIGURES 6–13. Representative habitats of coastal sand-perching Lasiopogon species collected for this revision. (6) Oregon: Lincoln Co., Gleneden Beach, NW tip of Salishan Spit, 17.v.2012 (L. actius on foredune, L. tumulicola sp. nov. in backdunes). (7) Washington: Grays Harbor Co., Westhaven State Park, dunes 2 mi NW of Westport, 20.vi.2013 (L. actius). (8) Oregon: Lincoln Co., Newport, Agate Beach State Park dunes, 21.vi.2013 (L. dimicki). (9) California: Humboldt Co., Clam Beach County Park ~5 mi SE of Trinidad, 15.v.2012 (L. canningsi sp. nov.). (10) California: San Mateo Co., Half Moon Bay State Beach, 5.vi.2013 (L. arenicola). (11) California: Monterey Co., Pacific Grove golf course, dunes in SW corner, 11.v.2012 (L. asilomar sp. nov.). (12) California: Santa Barbara Co., Rancho Guadalupe Dunes 1 mi S of parking lot, 9.v.2012 (L. littoris). (13) California: San Luis Obispo Co., Montaña de Oro State Park, dunes @ Sand Spit trailhead, 12.iii.2014 (L. bitumineus sp. nov., L. littoris weeks later).