Syringogaster plesioterga Marshall & Buck, 2009

Marshall, S. A., Buck, M., Skevington, J. H. & Grimaldi, D., 2009, A revision of the family Syringogastridae (Diptera: Diopsoidea), Zootaxa 1996 (1), pp. 1-80 : 56-59

Syringogaster plesioterga Marshall & Buck , new species

Figs. 46–49; Plates 3H, 4D–E, 5D,F; Map 8

DESCRIPTION: Head: Frons and postocciput brown, face, gena, and postgena orange, ocellar tubercle raised and black. Vertex weakly convex at middle. Ocellar triangle raised and shining, bare, bordered on each side by a row of four small inclinate bristles, almost parallel-sided on upper part, anterior apex broadly rounded and separated from frontal margin by 3X scape length. Remainder of frons tomentose and dull. Anteromedial surface of pedicel shining. Ocellar bristles strong. Parafacial with a few long hairs near lower facial margin; shining vibrissal angle without bristles. Subgena flat and shining, slightly higher than gena at middle, gena with only fine pale setulae. Supracervical collar narrow, pale, three times as long as pronotum dorsomedially.

Thorax: Pronotum with an anterolateral carina on each side, medially very short, with two dark diagonal lines. Antepronotum and propleuron shining, bare. Thorax orange except for black, subquadrate humeral pit, humeral carina, small scutal spots opposite anterolateral corners of scutellum, posterior margin of katepimeron, metapleuron (including postmetacoxal bridge) and metasternum. Notum tomentose on posterior 3/4 only, anterior quarter (anterior to humeral carina) shining; humeral carina large, twice as wide as humeral pit. Notopleural carina small and triangular, supra-alar carina weak. Mesopleuron almost entirely shining; upper posterior corner of anepisternum with sparse tomentum, lower anepisternum, katepisternum and anepimeron with sparse, fine golden bristles. Anterior prespiracular process forming a small, black, flat lobe; posterior prespiracular process twice as large, forming a shining triangle along anterior face of spiracle. Subspiracular ridge black, weakly developed, with a low, bare anterior lobe and a dorsally tomentose, ventrally shining posterior lobe. Fore coxa, trochanter and fore femur white to pale yellow, fore tibia and most of fore tarsomere 1 dark brown, apex of tarsomere 1 and distal tarsomeres yellow. Anteroventral margin of distal part of fore femur with a row of 7–12 short, stout black bristles, other femoral bristles pale. Mid femur white basally, rest of leg pale brown to yellow. Mid tarsomeres 1–3 and basal half of tarsomere 4 with antero- and posteroventral sawlines. Hind coxa and trochanter black. Hind femur with a white basal ring followed by a brown ring of similar length; remainder of leg yellow. Hind femur evenly convex on dorsal surface; ventral surface with two rows of stout bristles, anterior row of 9–12 bristles extending over distal 2/3 of femur, posterior row shorter. Hind tibia with apicoventral lobe small. Hind tarsus with sawlines on tarsomeres 1–4. Metanotum orange with black lateral condylar articulations with condyles of postnotum and tergite 1. Wing as described for S. figurata .

Abdomen: Abdominal tergites largely shining. Syntergite 1–4 narrow at base, gradually tapering to an apex 3X as wide as base, length 2X width at apex, surface bare and shining with a few scattered setulae, tergite 1 with indistinct transverse wrinkles. Background color of abdomen orange-yellow, tergite 2 narrowly dark brown medially, tergite 3 broadly black medially and along anterior and posterior borders; tergite 4 black on anterior half and narrowly dark brown medially. Tergite 4 fused to tergite 3. Tergite 5 yellow with a median longitudinal brown strip; female with apical tergites brown and cerci yellow.

Female terminalia: Four spermathecae in two pairs, each pair made up of short-stemmed but distinctly separate, dark, acorn-shaped spermatheca; each spermatheca ringed by grooves and with a narrow conical cap.

Male terminalia: Tergites 5 and 6 brown, unmodified, ventrolateral margins straight; spiracles in membrane. Sternites pale, 1–4 narrow and elongate, sternites 5 and 6 short and transverse, not divided medially; synsternite 7+8 narrow ventrally; left spiracle 7 considerably more dorsal than right spiracle, sternite 8 pale brown and shining dorsally. Epandrium and surstylus pale. Epandrium much wider than long. Cercus small, much shorter than the large mitt-shaped surstylus, latter with 1–2 apical bristles that are about half as long as surstylus. Hypandrium without internal interruptions or articulations; anterior U-shaped portion forming simple ventral band with moderately developed anterior apodeme; hypandrial bridge narrow. Pregonite large and broad; distally rounded ventral hypandrial lobe relatively short and stout, long-setose. Phallapodeme narrow and simple, without conspicuous posterolateral plates. Basiphallus narrowly cylindrical at base but greatly expanded apically; distiphallus complex, strongly curved up left side of postabdomen, apex bulbous with anterior, spinulose, and posterior finely striate membranous areas; preapical forked sclerite present, its ventral prong broad, triangular.

TYPE MATERIAL: Holotype ♂ ( USNM) and 8♀ paratypes ( USNM): ECUADOR. Pto. Orellana., Río Tiputini, 0º38.2’S, 76º8.9’W, 12–26.viii.1999, W. Mathis, A. Baptista & M. Kotrba. Other paratypes: ECUADOR. Napo, Res. Etnica Waorani, 1 km S Onkone Gare Camp, Trans. Ent., 220 m, 0º39’10”S, 76º26’W, 10.ii.1995, insecticidal fogging of mostly bare green leaves, some with covering of lichenous or bryophytic plants in terra firme forest, Trans. 7, Sta. 5, T. L. Erwin et al., Project MAXUS Lot #994 (1♂, USNM); same as previous locality but lots 710, 766, 855, 871, 888, 934, 1406, 1445, 1499 (9♀, USNM); Tiputini Biodiversity Station , 216 m, 0º37’55”S, 76º8’39”W, 5.ii.1999, Trans. 8 and 10, insecticidal fogging of mostly bare green leaves, some with covering of lichenous or bryophytic plants, T. L. Erwin et al., Lots #2086, 2096 (1♂, 1 ♀, USNM); same as previous record but lots 2012, 2029, 2031, 2032, 2063, 2064, 2065, 2087 (4♂, 5♀, USNM); Puerto Misahuallí , 350 m, ii.1983, M. Sharkey (3♂, CNCI); Napo, Huahua Sumaco , km 44 on Hollín – Loreto Rd., 21.xii.1989, malaise trap, M. & J. Wasbauer & H. Real (1♂, CSCA). PERU. [Río] Pichis , “Pto. Bermudes” [= Puerto Bermúdez], 15.xii.1903, W. Schnuse, 1911 (one headless ♀, SMTD, “ Syringogaster n.sp. det. W. Hennig ”); Madre de Dios, Manú National Park , Cocha Cashu Biological Station , 380 m, 12–20.x.1986, malaise trap, K. Petren (1♂, ROME, ROM868011 ); Manú, Erika (near Salvación), 550 m, 5–6.ix.1988, A. Freidberg (2♀, USNM); Manú, Río Manú , Pakitza, 250 m, 12º7’S, 70º58’W, 9–23.ix.1988, W.N. Mathis & A. Freidberg (1♂, USNM); Monsón Valley , Tingo María, 9.x.1954, E.I. Schlinger & E.S. Ross (1♂, USNM).

ETYMOLOGY: The name “ plesioterga ” refers to the relatively broad, presumably plesiomorphic, syntergite 1–4.

COMMENTS: This species is closely related to S. figurata (see comments below that species), and to S. atricalyx , from which it differs most obviously in body color. Syringogaster plesioterga has the metapleuron dark in stark contrast to the orange mesothorax, whereas the thorax of S. atricalyx is uniformly blackish brown. The terminalia of these species are also very similar (see comments below S. atricalyx ). S. plesioterga and S. atricalyx also differ slightly in chaetotaxy. The latter species has 10–13 stout anteroventral spines of the hind femur covering almost the entire length of the tibia, in contrast with S. plesioterga which has 9–12 spines restricted to the distal ¾ of the femur. Similarly, the front tibia of S. plesioterga has 9–12 distal spines while that of S. atricalyx has 10–16.