Platypalpus canus Melander

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 : 47-48

Platypalpus canus Melander

( Figs. 24–27 )

Platypalpus canus Melander, 1902: 220 , figs 29, 40, 45. Type locality: Los Angeles, California ( USA).

Type material examined. LECTOTYPE (here designated to avoid any future confusion over the identity of this type series), 3 labelled: Los Angeles/ Co., Cala./ xii.22.96; R. canus / TYPE Mel. [species name hand-written]; Cotype/ Platypalpus / canus Mel. [red, species name hand-written]; ALMelander/ Collection/ 1961 ( USNM). PARALECTOTYPES: 1 [sex?, abdomen broken], same data as in lectotype ( USNM). 1 3, same data as in lectotype ( USNM). 1 [sex?, abdomen broken], Los Angeles Co., Cala., xii.22.96; Cotype No. 29168 U.S. N.M. [red]; JM Aldrich Collection; Platypalpus canus Mel. [hand-written]; Platypalpus canus Mel. [hand-written] ( USNM).

Additional material examined. USA. California: 1 3 [terminalia dissected], StanU., 27.i ..1906 ( USNM) 1 Ƥ, StanU., 4.ii.1906 ( USNM); 1 Ƥ, Redwood City, 8.ii.1953, P.H. Arnaud ( CAS).

Recognition. Mid-sized species with 2 pairs of vertical bristles; antenna with scape and pedicel yellow, postpedicel short, black; thorax entirely densely light greyish pollinose, with acrostichals arranged in 2 close irregular rows; legs almost entirely yellow, only last tarsomere somewhat darkened; mid tibia with short, black, claw-like apical spur in male and unmodified in female.

Re-description. Wing length in lectotype 2.6 mm. Male. Head black in ground-colour. Frons broad, densely light grey pollinose, widened toward ocellar tubercle. Face narrow, concolorous with frons. Ocellar tubercle with 2 long brownish yellow proclinate anterior and 2 short posterior bristles. Two pairs of long brownish yellow verticals. Occiput densely light grey pollinose, with numerous thin yellow to pale setae of different lengths. Antenna with scape and pedicel yellow, postpedicel and stylus brown to black; postpedicel short, about 1.5X as long as wide (1.6X in lectotype); stylus nearly 2.0X as long as postpedicel (1.9X in lectotype). Proboscis short, brownish yellow. Palpus small, elongate oval, yellow, with several short pale setae.

Thorax brown in ground-colour, entirely densely light greyish pollinose, katepisternum without shining spot; with yellowish to brown setation (stronger bristles varying in colour but prescutellars and scutellars usually paler). Postpronotal lobe large, subglobular, with 1 long inclinate bristle and several setulae. Mesonotum with 1 moderately long presutural supra-alar, 2 long 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 uniserial, long, prescutellars longest; acrostichals arranged in 2 close irregular rows, short, lacking on prescutellar depression.

Legs almost entirely yellow, only last tarsomere somewhat darkened. Fore femur thickened, with rows of anteroventral and posteroventral dark strong setae becoming longer and paler basally, pubescent ventrally. Fore tibia rather slender, covered with short unmodified setae. Mid femur about 1.5 times narrower than fore femur; with double row of black ventral spinule-like setae longer basally; no posteroventral bristles. Mid tibia with short, black, claw-like apical spur, with spinule-like setulae ventrally. Hind femur with short anteroventral setae. Hind tibia unmodified, covered with short setae. Tarsi of all legs unmodified.

Wing hyaline, with brownish yellow veins. One long brown costal bristle. Veins R4+5 and M straight and parallel near wing margin; CuA2 slightly sinuate; cells br and bm long, contiguous, of subequal width. Squama yellow, with pale setae. Halter pale yellow.

Abdomen brown in ground-colour, finely greyish pollinose, mostly covered with short yellowish setae longer on pregenital segments. Terminalia ( Figs. 24–27 ) moderately large, brown; right cercus long, rather digitiform, narrowed apically, with unmodified setae of different lengths; left cercus similar to right cercus; right epandrial lamella as in Figure 24 , with several unmodified setae of different lengths on apical part; right surstylus barely differentiated from epandrium; left epandrial lamella long, narrow, rather subrectangular, with unmodified setae; hypandrium with some spine-like projections subapically.

Female. Similar to male. Mid tibia without apical spur. Abdominal segment 8 densely pollinose; cercus elongate.

Distribution. USA (California).

Remarks. Melander (1902) described this species based on thirteen specimens collected from Los Angeles Co., California, in December. The lectotype has no left wing. Platypalpus canus can be readily distinguished from all Nearctic species of the P. hackmani group by the male that possesses a short, black, claw-like apical spur on the mid tibia (absent in the female and in both sexes of the other species). Also, in this species the dorsocentral bristles are long and uniserial (vs. short and at least biserial in other species). Presumably the claw-like mid tibial spur of the male allowed Melander to recognize this species as a member of Platypalpus , unlike the other three species that he described in this group.

Figures

FIGURES 24 – 27. Platypalpus canus Melander, male. 24. right epandrial lamella, lateral view. 25. cerci and epandrium, dorsal view. 26. left epandrial lamella and left cercus, lateral view. 27. hypandrium, right lateral view.