Platypygus americanus Melander

Gharali, Babak, Evenhuis, Neal L. & Almeida, Jorge, 2013, World synopsis of described species of the genus Platypygus Loew (Diptera: Mythicomyiidae: Platypyginae), Zootaxa 3745 (2), pp. 199-242 : 203-205

Platypygus americanus Melander

( Figs. 1 , 2 )

Platypygus americanus Melander, 1950: 140 . Painter & Painter, 1965: 415. Cole & Schlinger, 1969: 238. Hull, 1973: 261. Evenhuis, 1983: 462; 2002: 25. Hall & Evenhuis, 1986: 326. Poole, 1996: 75.

Material examined. Type: USA: 1 female holotype from Mountain Home Canyon, west slope of San Bernardino Mountains, San Bernardino County, California, 3 June 1946, A.L. Melander (USNM). Non-types: USA: 4 females, California, Riverside County, 11 km N. Pioneer Town, 5 May 1961, D.M. Fox (UCR).

Notes on types. The “small supra-antennal spot” on the frons in the original description in Melander (1950) is not a pigmented mark but a grease mark. The frons is completely yellow in the holotype. The holotype female is greasy on the wings and head, otherwise is in fair condition. There is a small tear at the base of the left wing and the right antennal segments beyond the pedicel have broken off and are missing.

Diagnostic features. Face and frons yellow; postgena without posterior extension ( Fig. 1 a); occiput black; pronotum with small orange mark dorsomedially; mesonotum yellowish white with three longitudinal orange stripes, with moderately dense white hairs; scutellum yellowish white with white hairs; lateral margin of mesonotum yellowish white; spot next to transverse suture absent ( Fig. 1 c); pleura completely yellowish white without black mark; halter yellowish white; crossvein r-m at middle of cell dm ( Fig. 1 b); legs yellowish white except two last tarsal segments blackish; abdomen yellowish with short adpressed whitish hairs dorsally.

Female genitalia ( Fig. 2 ). [Note: Hall & Evenhuis (1986: 328) illustrated the female genitalia but did not provide a description. We here give the first description of the female genitalia.] Furca U-shaped, sclerotized, lateral arms thin, birfurcate apically, connected by thickly sclerotized slightly bilobed bridge, with two small linear sclerites next to genital orifice; common spermathecal duct very short; each spermathecal duct divided into two sections, basal section, transversely striated, long, broad, apical section narrow and smooth duct, without distinct sperm pump or valves; basal part of median spermathecal duct narrower than that of lateral ducts, without striation, twisted spirally on basal half, thin, straight on distal half toward reservoir; lateral spermathecal ducts about 3 times width of median duct; spermathecal reservoirs obovate, slightly indented medially, with short and dense canaliculi apica64lly.

Distribution. United States (California).

Remarks. Hall & Evenhuis (1986) illustrated the adult habitus of Platypygus americanus Melander, 1950 and its female genitalia and this species was later transferred to Cyrtisiopsis by Evenhuis (2002). By checking the holotype it was clearly revealed that there is no long and acute posterior extension of the postgena (its presence a diagnostic feature of Cyrtisiopsis ). Also, the female spermathecae of P. americanus ( Fig. 2 ) contains a spirally twisted median duct that is much narrower than the lateral ducts. This character, as mentioned above, is seen consistently in the spermathecae of the known dissected species of Platypygus . Further, P. americanus has an uncurved reservoir similar to species of Platypygus while a curved spermathecal reservoir is seen in the genus Cyrtisiopsis . Also in the wing of P. americanus , cell br is longer than bm cell, while species of Cyrtisiopsis have br cell equal in length to bm cell. As a result, we feel P. americanus was correctly described in the genus Platypygus by Melander (1950) and here we return it to its original combination as Platypygus americanus . The males of this species are still unknown.

Figures

FIGURE 1. Platypygus americanus holotype: a — lateral view, b — wing, c — dorsal view of mesonotum and abdomen.

FIGURE 2. Platypygus americanus female genitalia. Abbreviations: c = canaliculi, s. r. = spermathecal reservoir, a. s. d. = apical spermathecal duct, b. s. d. = basal spermathecal duct, c. s. d. = common spermathecal duct, f. = furca, s. = sclerite adjacent to genital orifice.