Robustagramma macrosternum Cui and Marshall, 2005

Marshall, Stephen A. & Cui, Yongsheng, 2005, Systematics of Robustagramma, a new genus of New World Sphaeroceridae (Diptera), Zootaxa 1026 (1), pp. 1-122 : 38-39

Robustagramma macrosternum Cui and Marshall , new species

( Figs. 67–73 , 368 )

Body length 1.4–2.2 mm. General color dark brown, moderately pollinose.

Head: Face, gena, antenna and lower frons reddish to dark brown, head otherwise fuscous. Interfrontal bristles in 3 pairs (occasionally in 4 pairs). Two orbital bristles, anterior orbital bristle ca. 3/4 as long as posterior. Uppermost orbital setula present between orbital bristles; lower orbital setulae smaller. Postvertical bristles convergent, over half as long as inner occipital bristle. Postocellar bristles small or absent. Eye height ca. 2.9–3.1 times genal height. Arista subequal in length to head height, aristal hairs over 3 times as long as basal width of arista.

Thorax: Prosternum narrow, bare. Dorsocentral bristles in 2 postsutural pairs, anterior postsutural dorsocentral bristles only slightly longer than acrostical setulae but shorter than middle prescutellar acrostichal bristle. Acrostichal setulae in 8–10 rows between anterior dorsocentral bristles; usually two pairs of setulae between prescutellar acrostichal and dorsocentral bristles. Scutellum with apical scutellar bristles ca. 1.7 times length of scutellum. Posterodorsal katepisternal bristle ca. 2/3 as long as distance between bristle base and wing base; anterodorsal katepisternal bristle small. Halter knob pale brown; stem yellow. First costal sector slightly thicker than second costal sector in anterior view. Length ratio of second to third costal sector ca. 0.58–0.63. Costa ending before wing apex, extending past R 4+5 by no more than one vein width. Distal half of R 2+3 gradually curved forward; discal cell without appendices. Tarsi and fore tibiae yellow. Mid tibia with a small dorsal proximal bristle, a small anterodorsal bristle at middle, and an anterodorsal, dorsal and posterodorsal distally; distal dorsal bristle small. Mid femur with two anterior subapical bristles and a small posterodorsal apical bristle. Mid tibia of male also with a small apicoventral and several short, stout ventral bristles on distal 2/5, two irregular rows of 9– 10 ventral proximal bristles and a row of 5 anteroventral bristles on basal third.

Male abdomen: All abdominal tergites uniformly dark and similar in length. Dorsomedial length of epandrium ca. 0.3X length of sternite 8. Sternite 5 exceptionally large, over 3 times as long as sternite 4, with many small club­like scales on posteromedial margin, a distinct borderline on left half, and two patches of strong bristles on anteromedial area. Surstylus entirely setose, with 2 or 3 spine­like apical bristles. Cercus slightly shorter than surstylus, pointed apically in lateral view. Whip­like sclerites of distiphallus nodular. Ejaculatory apodeme small, ca. 0.2X as long as aedeagal apodeme.

Female abdomen: Tergites 1–7 uniformly pigmented and entire. Sternite 7 elliptical; sternite 8 reduced to 2 minute sclerites. Spermathecae spherical with short ducts, paired ducts slightly longer than spermatheca and single duct slightly shorter than spermatheca.

Holotype (♂, DEBU): PERU: Loreto. Campamento San Jacinto , 175–215m, FIT, 5.vii.1993, R. Leschen.

Paratypes: Same data as holotype, but dated 7.vii.1993 (1 ♀, DEBU) , 10.vii.1993 (1 ♀, DEBU) . VENEZUELA: Bolívar. Km 40 Sta. Elena ­Icabaru Rd. , 220m (1 ♂, 1 ♀, DEBU) , 100m (2 ♀, DEBU) , 4–6.viii.1986, B. Gill.

Etymology: This specific epithet, macrosternum , refers to the unusually large sternite 5 of the male.

Figures

FIGURES 67­73. Robustagramma macrosternum sp. nov.: 67, posterior view of male terminalia; 68, lateral view of male terminalia; 69, lateral view of male internal genitalia; 70, male sternite 5; 71, dorsal view of female terminalia; 72, ventral view of female terminalia; 73, spermathecae.

FIGURES 363–370. Robustagramma spp. wings (not to scale): 363, R. atratum sp. nov.; 364, R. lingulatum sp. nov.; 365, R. setilamella sp. nov.; 366, R. robustinervus sp. nov.; 367, R. binitidum sp. nov.; 368, R. macrosternum sp. nov.; 369, R. longistylum sp. nov.; 370, R. hebes sp. nov.