Platypalpus arnaudi (Melander) Melander, 2012

Shamshev, Igor & Grootaert, Patrick, 2012, Proposed change in status of the Nearctic genus Charadrodromia Melander (Diptera: Hybotidae, Tachydromiinae), with description of four new species, Zootaxa 3525, pp. 35-50 : 37-38

Platypalpus arnaudi (Melander) comb. nov.

( Figs. 1–5 )

Charadrodromia arnaudi Melander, 1960: 129 . Type locality: Corte de Madera Creek, near Portola, California, San Mateo County ( USA).

Type material examined. PARATYPES: USA: 4 3, 4 Ƥ, CAL. vic. Portola Corte de Madera Cr., S. Mat. Co. xii–5–59, P.H. Arnaud, Jr.; Paratype, Charadrodromia arnaudi 3 A.L. Melander [yellow label]; Collection of Paul H. Arnaud, Jr ( USNM). 1 3, 1 Ƥ, same data; Paratype, Chersodromia arnaudi Mel. , CNC No 19172; 1 Ƥ, same data, CNC No 69192. 1 3, Corte de Madera Cr. near Portola, CAL., San Mateo County, xi–21–1959; P.H. Arnaud Collector; Paratype Charadrodromia arnaudi 3 A.L. Melander [yellow label]; Collection of Paul H. Arnaud, Jr ( USNM).

Additional material examined. USA. California: 2 3, 3 Ƥ, San Mateo Co., Redwood City, 2.i.1961, P.H. Arnaud, Jr. ( CAS): 1 Ƥ, Marin Co., Novato, 17–20.i.1963, E.L. Kessel & P.H. Arnaud, Jr. ( CAS): 2 Ƥ, Marin Co., Inverness, 1–13.xii.1963, P.H. Arnaud, Jr. ( CAS): 1 3, 1 Ƥ, same locality, 14–29.xii.1963, P.H. Arnaud, Jr. ( CAS); 1 3, 10 Ƥ, Alameda Co. Sunol Reg. Wilderness, along Indian Joe Cr., 7.iii.1979, D.D. Wilder ( CAS); 2 Ƥ, same locality, 29.iii.1979 ( CAS); 1 3, Contra Costa Co. Briones Reg. Park, along Alnamba Trail, on Ridge, 23.iii.1979, D.D. Wilder ( CAS); 24 3, 37 Ƥ, Marin Co., Copper Mine Gulch, 15.ii.1977, D.D. Wilder ( CAS); 1 3, Angwin, Napa Co., 9.ii.1969, T. Griswold ( CAS); 1 Ƥ, Napa Co., N side Howell Mt., 2 mi. NNE Angwin, 1300 ft., 10.1977, H.B. Leech ( CAS); 1 Ƥ, same locality, 8.i.1975, H.B. Leech ( CAS); 2 3, 2 Ƥ, same locality, 25.xi.1972, H.B. Leech ( CAS).

Recognition. Mid-sized species with 2 pairs of vertical bristles; antenna with scape and pedicel yellowish, postpedicel black, about 2.5 times as long as wide; thorax almost entirely finely greyish pollinose, katepisternum with large shining spot, acrostichals arranged in 4 irregular rows; legs almost entirely yellow, only last tarsomere darkened, mid tibia without apical spur.

Re-description. Body length 1.4–1.7 mm; wing length 1.9–2.0 mm. Male ( Fig. 1 ). Head black in groundcolour. Frons broad, densely light grey pollinose, widened toward ocellar tubercle. Face narrow, concolorous with frons. Ocellar tubercle with 2 long brown to yellowish brown proclinate anterior and 2 short posterior bristles. Two pairs of long brown to yellowish brown verticals. Occiput finely greyish pollinose, with numerous thin yellow to pale setae of different lengths. Antenna with scape and pedicel yellow to brownish yellow, postpedicel and stylus black; postpedicel conical, about 2.5X as long as wide; stylus as long as or slightly longer than postpedicel. Proboscis short, brownish yellow. Palpus small, yellow, pale pubescent, with several short pale setae.

Thorax brown in ground-colour, almost entirely finely greyish pollinose, sternopleuron with large shining spot; with pale to yellow setation. Postpronotal lobe with 1 long inclinate bristle. Mesonotum with 2 notopleurals, 1 postalar and 4 scutellar bristles (apical pair very long and cruciate, lateral pair very short); additionally, notopleural depression with several minute setulae and similar setulae present behind postpronotal lobe and on postsutural supra-alar space; dorsocentrals arranged in 2 irregular rows, lateroclinate, short, 2 prescutellars long; acrostichals arranged in 4 irregular rows, short, lateroclinate anteriorly, lacking on prescutellar depression.

Legs almost entirely yellow, only last tarsomere darkened; mostly with pale to yellow setation. Fore femur and tibia slightly thickened, covered with short setae. Mid femur as wide as fore femur; with double row of mostly black ventral spinules; no posteroventral bristles. Mid tibia without apical spur, with spinules ventrally. Hind femur with short anteroventral setae. Hind tibia unmodified, covered with short setae. Tarsi of all legs unmodified.

Wing ( Fig. 2 ) hyaline, with brownish yellow veins. One short costal bristle. Veins R4+5 and M1+2 straight and parallel near wing margin; CuA2 oblique; cells br and bm of subequal length but bm broader than br. Squama yellow, with pale setae. Halter pale yellow.

Abdomen brown in ground-colour, finely greyish pollinose, covered with short pale setae. Terminalia ( Figs. 3–5 ) rather large, concolorous with abdomen; left cercus digitiform, gradually narrowing, longer than right cercus, covered with unmodified setae; right cercus digitiform, covered with unmodified setae; left epandrial lamella subrectangular, with short narrow projection apically, with short to moderately long setae ventrally; right epandrial lamella rather elongate oval, with moderately long setae ventrally; right surstylus small, subtriangular.

Female. Similar to male. Abdominal segments 6–7 retracted and only partly visible; segment 8 finely pollinose; cercus elongate.

Distribution. USA (California).

Remarks. Melander (1960) described this species based on numerous specimens taken from “Corte de Madera Creek, near Portola, California, San Mateo County”. Platypalpus arnaudi can be readily distinguished from other Nearctic species of the P. hackmani group by a large shining spot on the katepisternum and long postpedicel.

Figures

FIGURES 1 – 5. Platypalpus arnaudi (Melander), male. 1. habitus, lateral view. 2. wing, dorsal view. 3. right epandrial lamella, lateral view. 4. epandrium with cerci and hypoproct, dorsal view. 5. left epandrial lamella and left cercus, lateral view.