Syringogaster cressoni Prado

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 : 37-40

Syringogaster cressoni Prado

Figs. 29–32; Plate 2C; Map 5

Syringogaster cressoni Prado, 1969: 18 .

Syringogaster brunnea auctt., nec Cresson, 1912: Cresson, 1914; Hennig, 1958.

DESCRIPTION: Head orange except slightly darker ocellar tubercle. Vertex weakly convex at middle. Ocellar triangle shining, bordered on each side by a row of four minute inclinate bristles, strongly tapered and triangular, anterior apex separated from frontal margin by scape length; remainder of frons tomentose and dull. Pedicel bare and shining anteromedially, otherwise tomentose. Ocellar bristles strong. Lower parafacial with thin black bristles; shining vibrissal angle with thin black bristles. Gena and subgena subequal at middle. Supracervical collar prominent and convex, 3–4X as long as middle of pronotum.

Thorax: Pronotum very short, black along anterior margin; mesonotum orange anteriorly, gradually phasing to dark brown on posterior half, middle part indistinctly vittate with median orange stripe flanked by darker stripes; lateral vestiges of transverse suture black; humeral pit black with vertical anterior surface extending laterally more than the width of the pit. Lower half of pleuron shining dark brown, upper half tomentose; propleuron and anepisternum orange, posterior part of pleuron and metathorax dark brown. Subspiracular lamella deeply bilobed, anterior lobe low and shining, posterior lobe much larger and entirely tomentose. Fore coxa, trochanter and femur pale yellow, tibia and basal ¾ of tarsomere 1 dark brown, distal tarsomeres yellow. Anteroventral margin of distal part of fore femur with row of 4–9 short, black spinules; posteroventral margin occasionally with a single distal spinule as well. Mid femur pale brown. Mid tarsomeres 1–3 with antero- and posteroventral sawlines. Hind femur orange-brown, ventral surface with two rows of stout bristles, anterior row of 12–15 bristles extending over distal 7/10 of femur, posterior row shorter. Hind tibia with apex weakly trilobate, lobes subequal. Anterior swalines of hind tarsomeres as described for mid tarsomeres but only tarsomeres 2 and 3 of hind leg each with a posterior row of 8–10 closely packed spinules on basal ¾. Wing as described for S. brunneina .

Abdomen: Abdomen strongly petiolate, tergites 1 and 2 parallel-sided, tergite 3 twice as wide at apex as base. Syntergite 1–3 densely microsculptured, sculpturing forming transverse ridges on tergite 1, densely tomentose. Abdomen orange, posterior margins of tergites slightly darker. Tergite 4 clearly separate from tergite 3.

Female terminalia: Tergite 7 with posteromedial emargination variable, very small to fairly long and deep. Four spermathecae in two pairs, each pair close together on short ducts, touching but not fused; each spermatheca smooth, broadly cylindrical, with a broad basal invagination and a narrower smooth, cylindrical cap (evagination) distally.

Male terminalia: Tergite 5 with ventrolateral margins unmodified, ventrolateral margin of tergite 6 narrowed laterally with a tapered anteroventral corner and a bulging, convex posteroventral corner. Spiracles 5 and 6 in tergite. Sternites 5 and 6 each divided into two small, equal, transverse-oval sclerites with about eight small bristles on each sclerite; sclerites of sternite 5 weakly pigmented and indistinct. Synsternite 7+8 with ventral part broad. Epandrium much longer than wide. Surstylus narrow and elongate, cercus twice as long as wide, surstylus 4X as long as greatest width, slightly curved anteriorly in apical fifth. Hypandrium with three pairs of breaks or weakenings: first between basal U-shaped portion and base of hypandrial arms, second between hypandrial bridge and mesal base of each hypandrial arm, third near middle of each hypandrial arm posterior to ventral hypandrial lobe. Hypandrial bridge very wide and robust. Anterior part of pregonite with a subquadrate ventral lobe ending in two triangular and short setose points. Postgonite dark and well-developed, widest near middle, extending well beyond point of articulation with pregonite. Posterior part of hypandrial arm broad, parallel-sided; anterior hypandrial arm elongate-triangular, distally setose. Basiphallus elongate, distal part of basiphallus asymmetrically expanded, left side forming a broad plate. Distiphallus curled up left side; broad, complex, with several flat, twisted plates and a relatively narrow, finger-like sclerite directed medially from right side.

TYPE MATERIAL (not examined): Holotype ♂ ( FIOC, #13.369) and paratype ♂ ( FIOC). BRAZIL. Pará , Fazenda Velha, 30.vi.1965, H.S. Lopes.

MATERIAL EXAMINED: BOLIVIA. Mapiri, “Sarampioni” [= Sarampiuni], 700 m, ii.1903 (specimen without abdomen, SMTD, second label reads “ Syringogaster brunnea det. W. Hennig 1939”); Mapiri, 15º18.6’S, 68º13’W, 720 m, 15.iii.2001, W.N. Mathis (2♂, 1♀, USNM); Mapiri, 15º17.8’S, 68º15.6’W, 750 m, 16.iii.2001, W.N. Mathis (1♀, USNM). ECUADOR. Napo, Puerto Misahuallí, 350 m, ii.1983, M. Sharkey (2♀, CNCI); Morona-Santiago, Miazal, 50 km SE Macas, 300 m, 4–7.i.93, M. & J. Wasbauer (1♀, CSCA). PERU. Cuzco, Quincemil, 780 m, 13–31.viii.1962, L. Peña (1♂, 1♀, CNCI); Yurac., 67 mi E Tingo María, 350 m, 4.x.1954, E.I. Schlinger & E.S. Ross (2♂, ♀, AMNH); Monsón Valley, Tingo María 9.x.1954, E.I. Schlinger & E.S. Ross (1♀, AMNH); Callanga (1♂, with an older label reading “ Syringogaster brunnea det. Kertész”, a newer red label reading “ Holotype Syringogaster peruviana Steyskal ”, and a smaller label reading “ CNC ”; the latter is the same as other labels Steyskal put on specimens from CNCI, and the specimen was borrowed from CNCI although it was possibly originally from the Hungarian Natural History Museum (see comments below)). SURINAME. Raleigh, Vallen-Voltzberg Res., Foengoe 4º43’N, 56º12’W, 26.i–15.ii.1982, J. Carpenter & D. Trail (1♀, AMNH).

COMMENTS: Cresson described S. brunnea on the basis of female specimens from Costa Rica in 1912, later (1914) publishing a paper describing a male from Callanga, Peru as the male of the same species. As suspected by Prado (1969), the male from Peru is not S. brunnea , but a new species named by him as S. cressoni Prado. Cresson described his Peruvian male on the basis of a specimen from the Hungarian Natural History Museum sent to him by Kertész, presumably the same specimen listed above from Callanga. Steyskal also recognized this species as different from brunnea , but he considered it to be different from cressoni and gave it the manuscript name “ S. peruviana ”. We can find no significant differences between the Peruvian material and the thorough description of Brazilian specimens by Prado, and concur with Prado that these are the same species although the ventral hypandrial lobe illustrated by Prado (1969) is somewhat more lobate than in the Peruvian material listed above. Feijen (1989) commented on the same material, adding that he had examined additional material from Peru and stating “it represents a still undescribed species with irrorated wings and four spermathecae”. It is not clear whether Feijen saw the male from Callanga that was the subject of Cresson (1914), but Syringogaster cressoni also has four spermathecae and irrorated wings. Prado (1969) was also correct in surmising that a specimen from Bolivia referred to by Hennig (1958) as S. brunnea was actually S. cressoni , although Prado did not see the specimen in question. The Bolivian specimen listed above, labelled “ Syringogaster brunnea det. W. Hennig 1939”, is almost certainly the fly referred to by Hennig (1958), and we consider it to be S. cressoni even though Hennig indicated the number of spermathecae to be three. The specimen examined by Hennig no longer has an associated abdomen, and S. cressoni was described on the basis of males only. All Syringogaster females examined during this study have four spermathecae.

Syringogaster cressoni can only be recognized based on a combination of characters: It differs from other species in the brunnea -group in possessing both ocellar bristles and fore femoral spines, a reddish (not dark) hind femur, and unmodified ventral margins of male tergite 5. The posteriorly projecting postgonite is also diagnostic (shared only with S. brunneina ). Syringogaster cressoni is the only species in the brunneina - subgroup lacking the deep posteromedial emargination of female tergite 7.