Lasiopogon arenicola (Osten Sacken)

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 : 39-41

Lasiopogon arenicola (Osten Sacken)

Lasiopogon arenicola Back, 1909: 297 .

Daulopogon arenicola Osten Sacken, 1877: 310 . Genus name an unnecessary replacement for Lasiopogon (see Taxonomic Notes).

Diagnosis. ( Fig. 31 ) A medium-sized species from central California coastal dunes; all macrosetae and setae lightcolored (white/gold); thoracic tomentum light grey with golden brown perimeter and brown dorsocentral stripes; abdominal tergites with brown tomentum basally and grey tomentum covering apical 50% of each tergite and extending laterally and up the midline in both sexes to divide brown tomentum into lateral spots. Epandrium strongly concave medially, curvature starts 35% from base; apical 20% bare of tomentum, with squared ventral edge. Ovipositor dark brown/black, acanthophorite spines pale brown.

Redescription. Body length ♂ 7.6–10.1mm; ♀ 8.2–10.4mm. Head. HW ♂ 1.84–2.21mm; ♀ 1.92–2.41mm. FW ♂ 0.38–0.49mm; ♀ 0.43–0.50mm. VW ♂ 0.67–0.89mm; ♀ 0.76–0.92mm. VW/HW = ♂ 0.36–0.41; ♀ 0.38– 0.40. FW/VW = ♂ 0.54–0.58; ♀ 0.54–0.57. VD/VW = ♂ 0.08–0.18; ♀ 0.13–0.14. GH/GL = ♂ 0.40–0.42; ♀ 0.34–0.35. Face and vertex with grey tomentum. Beard, labial, frontal and occipital setae all white; mystax usually a somewhat darker dirty white. Occipital macrosetae of moderate length; those behind the dorsomedial angle of the eye to 0.6mm and moderately curved anterolaterally; lateral and ventral macrosetae shorter, straighter. Frontal setae fine and short; orbital setae longer, extend just beyond the edge of the eye. Antennae. Brown to black, base of postpedicel rarely chestnut. Setae dirty white; no setae on postpedicel. Postpedicel rectangular, with straight dorsal and ventral margins, stylus moderately long, tapering. WPP/LPP = ♂ 0.30–0.37; ♀ 0.23–0.31. LAS/LPP ♂ 0.58–0.77; ♀ 0.52–0.67. Thorax. Prothorax grey, setae dirty white; postpronotal lobes grey to brownish grey, the lateral angle ferruginous, setae white. Scutum tomentum steelish-grey, sometimes brown around the perimeter. Dorsocentral stripes usually light brown bordered by tan, sometimes darker brown with a grey border; acrostichal stripes absent. Notal and acrostichal setae white; anterior dorsocentral macrosetae 5–8, white (to 0.9 mm), relatively fine and mixed with finer setae; 3–5 posteriors. Other macrosetae white with dirty white bases; postalars 3, with about 4 shorter setae; supra-alars 3–5 with 1 or 2 shorter setae; presuturals 3–4; posthumerals 1. Scutellar tomentum grey, ranging from silvery to brownish; rim strongly inflated, leaving a semi-circular line impressed inside the dorsal edge; apical macrosetae whitish, abundant (usually 8–10+ on each side) and mixed with many other long setae. Pleural tomentum grey, brownish on the lower anepisternum. Katatergite macrosetae dirty white, 8–10 with a few weaker setae; katepisternal setae sparse, moderately long, white; anepisternal setae 4–7, usually moderately strong (to 0.8mm) and mixed with other setae, a patch of short white setae on dorsal margin of sclerite; anepimeron with a single fine seta, white. Legs. Base color usually dark brown to black, sometimes reddish at joints of coxa/femur, femur/tibiae, and tarsal bases; tomentum of coxae and rest of legs grey, sparse. No coxal peg. Macrosetae on legs dirty white, finer setae white. Ventral setae on femur longer than femur width; dorsolateral macrosetae strong, mixed with many finer setae, 5–7 on profemur; longer on mesofemur (3–6) and metafemur (8–9). Protibia with longest macrosetae about 3 times longer than tibial width. Claws reddish brown over basal 70%, apically black. Wings. Veins dark brown, lighter in apical half; membrane transparent, milky white when viewed obliquely. DCI = 0.35–0.50. Halter yellow, with no spot. Abdomen. Cuticle dark brown/black basally, covered in grey tomentum except for semicircular patches of brown tomentum at tergite bases. Tergite 1 completely covered in light grey tomentum; on other segments, apical bands of light grey tomentum cover about half the length of the tergite and extend medially and laterally to the tergite base in both sexes. Tergites 2–5 each show a clear pair of brown spots; tergites 6 and 7 have the brown patches reduced to minor smudges. All tergites with relatively prominent and dense lateral setae. Abundant macrosetae on each side of tergite 1, setae on sides of tergites 2–3 longer than basitarsus, erect. Setae on side of tergites 4–7 about length of scape + pedicel. Sternite tomentum grey, setae white. Male genitalia. Epandrium and hypandrium/gonocoxite complex cuticle dark brown/chestnut; epandrium polished over apical 20%, otherwise covered in thin grey tomentum; covered in long white setae, setal brush yellowish white. Epandrium elongate, in lateral view the width about 45% the length, widest in basal third, dorsally and ventrally sinuate; apex right-angled ventrally, straightedged apically, and rounded dorsally. In dorsal view, medial margins of epandrium strongly curved, curvature starting 35% from the base of the epandrium; basal sclerite prominent. Phallus paramere sheath dorsally 60% the length of phallus; paramere sheath with small ventral flange near base; dorsal carina a narrow wave-like fin with rounded apex not projecting apically and ending well short of the gonopore. Ejaculatory apodeme in lateral view moderately bent dorsally in basal quarter, slightly recurved at apex; dorsal carina broadly fills gap. Subepandrial sclerite with triangular central unsclerotized area in basal 75%; spines blunt, sparsely distributed, especially basally.

Female genitalia. Undissected: Setae white, abundant, erect. Tergite 8 dark brown/black with posterior margin paler; sternite 8 dark brown/black laterobasally, yellowish brown/chestnut along midline; lateral lobe setae strong; hypogynial valves with fine setae, concentrated basally; cerci brown with pale setae; acanthophorite spines pale brown.

Variation. Most individuals have white or dirty white setae and macrosetae, but a few specimens are completely clothed in golden setae, yet otherwise indistinguishable in morphology or genetics. Similar golden morphs have been observed in several other Lasiopogon species ( L. canningsi sp. nov., L. monticola Melander , L. zonatus Cole & Wilcox ).

Type Material. LECTOTYPE (here designated) ♂ labelled: “[rectangular white label] Lone Mt. S. Francisco/ June 29 O.Sacken ”; “[rectangular white label] O. Sacken / West. Dipt”; “[square red label] Type / 12802”; “[rectangular white label] Museum of/ Comparative / Zoology ”; “[rectangular white label] MCZ-ENT 00012802 ”. Our lectotype label “ LECTOTYPE / Daulopogon ♂ / arenicola Osten Sacken / des. T.A. McKnight 2017 [red, black-bordered label]” and determination label “ Lasiopogon ♂ / arenicola/ (Osten Sacken) / det. T.A. McKnight 2017 [white, black-bordered label]” have been attached to this specimen. MCZ.

PARALECTOTYPES (6 examined): U.S.A.: CALIFORNIA: San Francisco [37.784 -122.444], 6.iv.[1876], Osten Sacken (3♂ 2♀ [2 pr in cop] MCZ, MCZ-ENT 00303441 – MCZ-ENT 00303443 ); Lone Mountain [37.772 -122.463], 29.vi.[1876], Osten Sacken (1♀ CNC, CNC 2161 ). Our paralectotype labels have been attached to these specimens.

Other Material Examined (57 specimens). U.S.A.: CALIFORNIA: San Francisco Co., [no loc], [?.]vi.[?], (1♀ USNM, USNMENT1100290 ) , 4.vi.1905, E.C. Van Dyke (1♀ CAS) , 10.iv.1907, E.C. Van Dyke (1♂ OSUC, OSUC 194391 ) , 24.iii.1920, A.J. Basinger (1♀ RBCM) ; Fort Funston [37.717 -122.504] , 16.iv.1960, G.I. Stage, R.R. Snelling (1♀ BPBM) , 5.iv.1987, R.L. Zuparko (1♀ EMEC) ; Golden Gate Park [37.767 -122.511] , 6.vi.1920, F.R. Cole (1♀ CNC) ; 6.vi.1928, F.R. Cole (1♂ LACM, LACM ENT 334017 ) ; San Francisco [37.784 -122.444] , 12.v.1915, M.C. Van Duzee (2♂ 2♀ OSUC, OSUC 194387 – OSUC 194389 , OSUC 194392 , 1♀ CAS) , 22.v.1915, M.C. Van Duzee (1♀ CAS) , 29.iii.1920, A.J. Basinger (1♂ FSCA) , 4.iv.1920, A.J. Basinger (1♂ FSCA) , 6.vi.1920, E.P. Van Duzee (1♂ CAS) , 18.iii.1933, E.S. Ross (1♀ CAS) , 30.v.1933, E.S. Ross (1♀ CAS) , 1.v.1947, E.L. Kessel (1♂ 1♀ CAS, 1♂ ESUW), E.S. Ross (1♂ 1♀ CAS, 1♀ FSCA, 1♂ RBCM) , 21.v.1949, C. Hildebrand (1♀ CAS) , 23.v.1949 (1♀ FISH) , 2.vi.1949 (1♂ FISH) , 9.v.1951, E.L. Kessel (1♀ CAS) , 18.iii.1960, G.I. Stage (1♂ 3♀ CAS, 1♂ FISH); San Francisco beach [37.763 -122.511] , 16.v.1951, E.I. Schlinger (1♂ CNC, 1♂ FISH, 1♂ FSCA), R.C. Bechtel (1♀ FISH) ; San Francisco sand dunes , 2.vi.1923, Carl D. Duncan (1♂ 1♀ UMMZ) , 12.vi.1923, Carl D. Duncan (1♂ OSUC, OSUC 194390 , 1♂ 1♀ UMMZ) ; San Mateo County., Half Moon Bay [37.462 -122.445] , 23.v.1937 (1♀ UCRC, UCRC ENT 449901 ) , R.C. Dickson (1♀ CSUC) , 24.v.1979, J. Powell (1♀ BEZA) ; Half Moon Bay State Park, 37.47997 -122.45096, T.A. McKnight (1♂ 1♀ [1 pr in cop] RBCM, 1♂ 1♀ [1 pr in cop] TAM, 2♂ 2♀ [4 EtOH] UMMZ); Santa Clara Co., Palo Alto [37.435 -122.095] , 11.v.1893, R.W. Doane (1♀ EMEC) , 11.v.1895, R.W. Doane (1♀ EMEC) .

Taxonomic Notes. Osten Sacken’s original description referenced 8 specimens that would be syntypes according to the modern ICZN Code. Prior to this publication, the accepted species concept of L. arenicola included L. asilomar sp. nov., a closely related species found allopatrically to the south from Santa Cruz County to San Luis Obispo County. These two species can be readily distinguished by comparing tergite tomentum patterns. For future stability, we are hereby designating one of Osten Sacken’s specimens as a lectotype, and others in this series as paralectotypes.

Loew (1874) proposed the genus name Daulopogon to replace Lasiopogon after he learned that Lasiopogon was a name already in use for a group of plants. However, since the plant and animal taxonomic codes are independent of each other, this was eventually recognized as an unnecessary emendation and Williston (1908) restored the name Lasiopogon . This species was originally described under the replacement name.

Etymology. No explanation given in the original description, but evidently from the Latin arena = sand, cola = inhabitant of; referring to the sand dune habitat of the species.

Distribution ( Fig. 37 ) Nearctic; USA: California; beach dunes of the San Francisco Peninsula. Type locality: U.S.A., California, San Francisco, “... on the sands about Lone Mountain...” ( Osten Sacken 1877).

Phylogenetic Relationships. Member of the bivittatus section, drabicolum group; likely the sister species to L. asilomar .

Natural History. Habitat: sand dunes. Perches on bare sand adjacent to low, scraggly vegetation ( Fig. 10 ). Dates collected: 29 March to 12 June. One specimen with a tiny arachnid on the proboscis that is presumably an undetatched prey item but there is no label confirming this.

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 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).