Lasiopogon littoris 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 : 62-64

Lasiopogon littoris Cole

Lasiopogon littoris Cole, 1924: 8 .

Diagnosis. ( Fig. 35 ) A very small species from central California beach dunes with uniform dusty grey tomentum and white setae. Antenna with squat postpedicel and elongate stylus; scutum silvery grey, practically without stripes or pattern; all setae on body white and relatively long and dense; abdominal tergites with dense grey tomentum; basal brown patches on tergites inconspicuous. Epandrium long, narrow, with ventral tooth, moderately concave medially; phallus apex broadly flattened, with dorsal corner pointed; dorsal carina a rounded triangular point near midpoint of aedeagal tube. Ovipositor brown; acanthophorite spines black.

Redescription. Body length ♂ 6.3–8.2mm; ♀ 6.4–9.5mm. Head. HW ♂ 1.59–2.03mm; ♀ 1.54–2.04mm. FW ♂ 0.39–0.49mm; ♀ 0.35–0.53mm. VW ♂ 0.69–0.85mm; ♀ 0.68–0.85mm. VW/HW = ♂ 0.42–0.45; ♀ 0.42–0.44. FW/VW = ♂ 0.49–0.58; ♀ 0.51–0.62. VD/VW = ♂ 0.14–0.17; ♀ 0.16–0.20. GH/GL = ♂ 0.35–0.47; ♀ 0.31–0.39. Face and vertex with silver-grey tomentum. Beard, labial, mystax, and all other setae white. Occipital macrosetae relatively fine and long; those behind the dorsomedial angle of the eye the longest (to 0.7mm) and usually moderately curved anterolaterally; lateral and ventral macrosetae shorter, straighter. Frontal setae fine and short; orbital setae longer and more prominent. Antennae. Brown, with faint grey tomentum except on polished stylus, which appears darker than basal segments. Setae on scape and pedicel white, no setae on postpedicel. Postpedicel short and squat; stylus very long and of even width, always longer than postpedicel. WPP/LPP = ♂ 0.48–0.50; ♀ 0.41–0.48. LAS/LPP ♂ 1.04–1.22; ♀ 1.04–1.17. Thorax. Prothorax grey, setae white; postpronotal lobes grey, the lateral angle ferruginous, setae fine, white. Scutum tomentum densely grey, sometimes faintly gold; dorsocentral stripes practically indiscernible, faintly darker from an angle. All macrosetae and setae white, acrostichal and notal setae fine, at least half as long as dorsocentral macrosetae; dorsocentral macrosetae long (to 0.8mm) amidst abundant fine setae, 4–6 anteriors, 4–5 posteriors; postalars 2–3; supra-alars 1–3; presuturals 1–2; posthumerals 0–1. Scutellar tomentum grey; apical scutellar setae dense, indistinguishable from surrounding finer setae. Pleural tomentum gold-grey. Katatergite macrosetae 6–7, often with some finer setae; katepisternal setae fine, wispy; setae along posterior and dorsal edges of anepisternum fine, 3–5 moderately prominent (to 0.8mm); anepimeron with 1–2 short wispy setae.

Legs. Base color black; tomentum grey. No coxal peg. All setae and macrosetae white. Ventral setae on femur shorter than or as long as femur width; dorsolateral macrosetae on profemur sparse (0–4) but mixed with many finer setae; stronger and less crowded on mesofemur (2–4) and metafemur (6–11). Protibia with ventral macrosetae 3 times longer than tibial width; apicomedial patch of short setae on protibia indistinct, white. Claws dark brown over basal 40%, apically black. Wings. Veins yellow-brown to brown, usually lighter proximally; membrane tinged brownish in oblique view, frosted in direct view. DCI = 0.45–0.56. Halter light brown to white, no spot, stem darker brownish. Abdomen. Tergite cuticle color black; thin brown tomentum on bases of tergites 2–4 (2–5 in female), grey tomentum covers apical 70–90% of each tergite (tergite 1 completely covered), extending anteriorly along lateral margins and midline to divide brown into indistinct lateral spots, overall color primarily silvery grey. Setae white; lateral setae as long as notal setae on tergite 1 and as long as postpedicel on all other tergites, dense in male but sparser in female; lateral macrosetae on tergite 1 white, fine, not prominent amidst surrounding setae. Dorsal setulae short, white. Sternite tomentum grey, setae white. Male genitalia. Epandrium and hypandrium/gonocoxite complex cuticle dark brown; covered in grey tomentum; setae white, setal brush yellowish white. Epandrium elongate, in lateral view the width about 45% the length, widest in basal third, with straight dorsal margin and sinuate ventral margin, apex rounded with broad ventral tooth. In dorsal view, medial margins of epandrium moderately concave, curvature starts 34% from base; basal sclerite strong. Phallus paramere sheath dorsally 58% the length of phallus; paramere sheath without ventral ornamentation; apex broad and flattened, ventral lip rounded and shallow, dorsal lip coming to a longer sharp point; dorsal carina a rounded triangular point near midpoint of aedeagal tube, very shallow in specimens from the north. Ejaculatory apodeme in lateral view slightly bent in basal quarter, with broad dorsal carina. Subepandrial sclerite with triangular central unsclerotized area in basal 79%; spines parallelsided, blunt, sparsely and evenly distributed.

Female genitalia. Undissected: Setae white, erect, abundant. Tergite 8 brown, paler apically; sternite 8 dark brown; hypogynial valves paler with very short setae; lateral lobes with moderate white macrosetae; cerci yellowish brown with short white setae; acanthophorite spines black.

Variation. A minor degree of divergence can be seen in COI barcode sequences (minimally 2.2%) and in morphology (e.g., depth of the phallus dorsal carina) between individuals from Morro Bay and from the Pismo dune complex to the south, which suggests that there has been some isolation of the populations on these two nearby beaches; however, we do not feel this warrants specific status. A similar biogeographic split has been observed in other flies found on these beaches, such as in the original description of Parathalassius abela Brooks & Cumming 2017 .

Type Material. HOLOTYPE ♂ (photos examined) labelled: “[rectangular white label] Pismo Cal/ iv.25.19”; “[rectangular white label] EPVanDuzee/ Collector”; “[rectangular white, black-bordered label] Lasiopogon / littoris/ Type Cole”; “[rectangular white label] California Academy/ of Sciences/ Type No. 1575”. CAS.

Other Material Examined (409 specimens). U.S.A.: CALIFORNIA: San Luis Obispo Co., Atascadero State Beach , dunes 1 km N of Morro Rock, 35.3793 -120.8626 , 12.v.1995, R.A. Cannings, H. Nadel (1♂ 2♀ LACM, LACM ENT 334047 – LACM ENT 334049 , 9♂ 5♀ RBCM, RBCM ENT 010-002812 , RBCM ENT 010-002814 ) , 9.v.2012, T.A. McKnight (1♀ RBCM, 1♂ TAM, 4♂ 1♀ [5 EtOH] UMMZ); Dune lakes 3 mi S Oceano [35.068 -120.615] , 1.vi.1972, J. Powell (3♂ 2♀ EMEC) , 26–27.iv.1973, J. Powell (1♂ EMEC) , 27.iv.1973, J. Powell (2♂ EMEC) , 6.vi.1973, J. Powell (2♂ EMEC) , 2.v.1974, J. Doyen (1♂ 1♀ [1 pr in cop] EMEC) , J. Powell (2♂ 3♀ EMEC) , 21.v.1976, J. Doyen (7♂ 3♀ EMEC) ; Dune lakes 7 mi S Oceano [34.977 -120.644] , 4–5.vi.1971, J.D. Pinto (1♂ UCRC, UCRC ENT 449973 ) , 20.v.1972, J.D. Pinto (3♂ 2♀ UCRC, UCRC ENT 449968 – UCRC ENT 449972 ) ; Grover City [35.122 -120.634], 27.iv.1959, E.G. Linsley (1♂ 1♀ EMEC) ; Morro Bay [35.361 -120.858] , 23.vi.1951, S.F. Bailey, R.M. Bohart (2♂ FSCA) , 30.iv.1962 (1♂ EMEC) , C.A. Toschi (9♂ 3♀ EMEC) , J. Powell (1♂ EMEC) , J.K. Drew (1♂ 2♀ EMEC) , P.D. Hurd (11♂ 3♀ EMEC) , R.L. Langston (9♂ 3♀ EMEC, 2♂ 3♀ FISH), R.W. Thorp (25♂ 13♀ EMEC, 1♂ RBCM), Timberlake (5♂ 1♀ UCRC, UCRC ENT 449957 – UCRC ENT 449961 , UCRC ENT 449963 ) , 2.v.1962, C.A. Toschi (2♂ 4♀ EMEC, 1♂ RBCM), R.W. Thorp (4♂ 4♀ EMEC) , 26.vi.1963, J.C. Hall (1♂ 1♀ UCRC, UCRC ENT 449975 – UCRC ENT 449976 ) , 26.iv.1968, D. Veirs (1♂ CAS, 2♂ 2♀ EMEC), J. Powell (3♂ 1♀ EMEC) , P.A. Opler (1♂ CAS, 14♂ 10♀ EMEC) , 26.v.1970, J. Wilcox (14♂ 10♀ CAS) , 27.v.1970, J. Wilcox (4♂ 2♀ CAS) , 27.v.1981, D.A. Powell (1♂ LACM, LACM ENT 334127 ) , 7.vi.1982, J. Wilcox (2♂ 1♀ CAS) ; Morro Bay , 1 mi N [35.379 -120.863] , 26.v.1970, J. Wilcox (1♂ FISH) , 5.v.1973, J. Doyen (3♀ EMEC, 1♂ RBCM); Oceano [35.095 -120.621] , 24.iv.1951, R.M. Bohart (1♂ FSCA) , 9.vii.1964, J. Wilcox (1♂ CAS) , 27.v.1970, J. Wilcox (2♂ 2♀ CAS) , 29.v.1970, J. Wilcox (1♀ BEZA) , 22.vi.1970, J. Wilcox (4♂ CAS) , 23.vi.1970, M.W. Stone (3♂ 3♀ CAS) , 14.vii.1970, J. Wilcox (1♂ BEZA) , 18.vi.1972, P.P. Perkins (1♂ FISH) ; Oso Flaco Lake [35.032 -120.627] , 11.v.1965, J. Powell (2♂ EMEC) , 22.vi.1965, M.E. Irwin (2♀ UCRC, UCRC ENT 449966 – UCRC ENT 449967 ) , 23.iv.1966, A.J. Slater (1♂ EMEC) , J. Powell (3♂ EMEC) , 12.iv.1967, P.A. Rude (1♂ EMEC) , 29.vi.1967, M.E. Irwin (1♂ UCRC, UCRC ENT 449965 ) , 27.iv.1968, D. Veirs (1♂ EMEC) , J. Doyen (1♂ 1♀ EMEC) , J. Powell (1♀ BPBM, 3♂ 2♀ EMEC, 1♀ RBCM), J.A. Chemsak (1♀ BPBM, 2♂ EMEC) , 1.vi.1972, J. Powell (1♂ EMEC) , 16.vi.1991, D.E. Russell (2♂ 2♀ BEZA) , 13.v.1995, R.A. Cannings (1♂ CUAC, 3♂ 3♀ RBCM, RBCM ENT 010-002811 , RBCM ENT 010-002813 ); Oso Flaco Lake Preserve dunes, 35.03316 - 120.62664 , 12.iii.2014, T.A. McKnight (1♂ [1 EtOH] UMMZ) ; 35.03187 -120.62658, 9.v.2012, T.A McKnight (1♂ 1♀ TAM, 1♂ 10♀ [10 EtOH] UMMZ) ; 9.iii.2013, T.A McKnight (2♂ 1♀ [3 EtOH] TAM, 1♂ [1 EtOH] UMMZ); Oso Flaco State Park , coastal dunes, 35.01533 -120.61783 , 11.iii.2007, M.E. Irwin (1♂ UAIC) , 13.iii.2007, M.E. Irwin (6♂ 2♀ UAIC) ; Pismo Beach [35.092 -120.629], v.1976, J. Doyen (1♂ EMEC) , 13.v.1956, I. Wilcox, J. Wilcox (4♂ 2♀ CAS, 1♂ EMEC, 1♀ UCRC, UCRC ENT 449964 ) , 13.v.1956, J. Wilcox (25♂ 22♀ CAS, 1♀ EMEC, 1♂ 1♀ ESUW, 4♂ 3♀ FISH, 1♀ UCRC, UCRC ENT 449962 ) , 23.iv.1960, J.A. Chemsak (1♀ EMEC) ; Pismo Beach State Park [35.087 -120.626] , 15.vii.1967, M.E. Irwin (1♀ UCRC, UCRC ENT 449974 ) ; Poly Hills [35.302 -120.655], 20.v.1962, E. Anderson (1♀ LACM, LACM ENT 334124 ) ; Santa Barbara Co., Rancho Guadalupe dunes 1 km S of parking lot, 34.94991 -120.65542 , 9.v.2012, T.A McKnight (1♀ RBCM, 2♂ 1♀ TAM, 6♂ 3♀ [8 EtOH] UMMZ); Santa Maria River beach dunes [34.967 -120.649], J. Doyen (2♂ EMEC) .

Etymology. No explanation given in the original description, but evidently from the Latin litoralis, littoralis = littoral, of the seashore.

Distribution. ( Fig. 41 ) Nearctic; USA, known only from central California coast between Morro Bay and Vandenberg Air Force Base. Type locality: U.S.A.; California, Pismo.

Phylogenetic Relationships. Member of the bivittatus section, perhaps sister to the new bivittatus group or to L. bitumineus . Cole (1924) observed that the antennae (with the short postpedicel and long stylus) are suggestive of Lissoteles Bezzi , another Stichopogoninae genus found along the Mexican coast; however, the face and genitalia of L. littoris are typical of Lasiopogon and this is evidently an example of convergent evolution.

Natural History. Habitat: upper beaches and beach dunes. Perches directly on bare sand, usually within a meter or two of a vegetation patch, such as Ericameria ericoides (Less.) Jepson and Carpobrotus edulis ( Figs. 12–13 ). Museum-vouchered specimens range from 9 March to 15 July, however, credible online reports have reported this species as early as 14 February (A. Abela pers. comm., see comment at https://bugguide.net/node/view/1040431; https://bugguide.net/node/view/1191730 shows a L. littoris from 16 February.) One female and one male specimens pinned with prey: Tethina Haliday in Curtis sp. ( Diptera : Canacidae ) and Parathalassius uniformus Brooks and Cumming ( Diptera : Dolichopodidae ); online photographs also show males feeding on Chironomidae ( Diptera , https://bugguide.net/node/view/901367), Cicadellidae ( Hemiptera , https://www.flickr.com/photos/44150996@ N06/13934554931), and Acari (https://bugguide.net/node/view/1056330, see Fig. 5 ). Oviposition observed as females burying their abdomen in the sand near beach burr plants ( Ambrosia chamissonis (Less.) E. Greene ) (see https://bugguide.net/node/view/1050787, Fig. 3 .) Can be extremely abundant on the sides of trails through the dunes; we have encountered hundreds in an hour’s walk. Completely sympatric with L. bitumineus , but L. littoris appears to have a slightly later emergence season and frequents dunes closer to the beach.

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).

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.