Mesoconius dianthus, Marshall, S. A., 2015

Marshall, S. A., 2015, Mesoconius Enderlein (Diptera, Micropezidae, Taeniapterinae) of Central America, Zootaxa 3914 (5), pp. 525-540 : 530-532

Mesoconius dianthus new species

Figs. 2A–2J

Description. Length (antenna to wing tip) 14–16 mm. Color: Orange except as follows: Antenna brown with basal fifth of first flagellomere yellow to orange. Ocellar triangle dark, lower frons sometimes dark, parafacial silvery. Thorax sometimes with diffuse dark anteroventral patches; foreleg with distal half to fifth of femur and all of tibia black, tarsus white or yellow; mid and hind femora orange but usually with black band at middle and often with black base, mid tibia and tarsus brown, hind tarsomeres 1–2 with similar pigmentation to fore tarsus (white or yellow). Abdomen with dark posterolateral patches on T2 and T3; pleuron pink to orange, paler ventrally.

Head: Epicephalon and paracephalon smooth and shining with no indication of striae, lower half of frons dull; frontal vitta velvety orange, posteriorly narrow but expanded into a microtrichose patch at level of postocellar bristles, widely separated from frons margin. Outer vertical bristle absent, inner vertical bristle strong, postocellar bristle strong. Upper fronto-orbital inserted at or above level of ocelli, one small but distinct lower fronto-orbital bristle. Upper face microsetulose, weakly carinate; parafacial and gena strongly silvery pruinose, subantennal areas shining brown. Palpus pale yellow.

Thorax: Cervical sclerite small, microtrichose except for a small, flat anterior portion. Notum subshining, uniformly and finely microtrichose, acrostichal setulae absent, dorsocentral setulae small but in a distinct row; postpronotal lobe microtrichose with some scattered small setulae, anterior margin vertical and bare. Katatergite prominent, with a nipple-like process. Vertical row of katepisternal bristles yellow. Coxae with anteroventral tufts of golden bristles.

Abdomen: Syntergite 1+2 very narrow basally, constriction between syntergites about half as wide as base of T3; length of T1+2 double length of T3.

Female abdomen: Bursa copulatrix broad and rugose; ventral receptacle large, with a distinct, parallel-sided apical part; spermatheca with a short, broad, striate common duct before splitting into ducts leading to paired and single spermathecae. Paired spermathecae large, distinctly striate, each on a separate narrow sinuate duct with a large ovate swelling near base; common duct of paired spermathecae long and indistinctly striate. Single spermatheca small, elongate; duct slightly shorter and narrower than paired duct, with a short constricted area at base of spermatheca.

Male abdomen: Sternite 5 lightly sclerotized, unmodified. Sternite 7 dark, with a broad anterior apodeme and an expanded, spatulate right apex. Epandrium and cercus small, cercus and posteroventral corner of epandrium setose, anteroventral corner of epandrium forming a parallel-sided lobe articulating with hypandrium. Hypandrium with a very broad, twisted anterior plate with distiphallus apex coiled into its right side. Postgonites small and divergent (directed laterally), with 4 small apical bristles. Basiphallus very small, frame-like; not extending beyond base of distiphallus. Basal distiphallus broadly tubular, gradually expanding to a large 2-chambered phallic bulb; distal part tapered and whip-like, distally coiled into right side of anterior hypandrial plate. Ejaculatory apodeme larger than epandrium.

Type material. Holotype (♂, INBC) and 4 paratypes (3 ♂, 1 ♀, DEBU): COSTA RICA. Puntarenas, Monteverde Biological Station, along lower trail, 10°18’7”N 84°48’10”W, 1500 m. 14.viii.2010, S.A. Marshall. Other paratypes ( INBC unless otherwise indicated): COSTA RICA. Heredia, Porrosati, Rio Ciruelas, 1900m, v.1990, A. Fernandez (1 ♂). Puntarenas, Monteverde Biological Reserve, 1500 m. cloud forest, 13.vi.2000, M. Buck (1 ♂, DEBU); Puntarenas, Monteverde Biological Station, 1500 m. sticky trap on tree trunk, 13–14.vi.2000, D. Bickel (1 ♀). Puntarenas, Pittier station, 1670 m. 4–23.i.1996, E. Navarro (1 ♂); Monteverde, cloud forest, 1700 m. 1– 5.v., Malaise, B.V. Brown (1 ♀); Puntarenas, Pittier station, 1800–2050 m. 26.vi.–4.vii.1995, M.A. Zumbado (1 ♀); Puntarenas, Monteverde Biological Reserve, La Cason Station, 1520 m. iv.1994, N. Obando (1 ♀); Puntarenas, Monteverde Biological Station, lower trail, cloud forest, 11.vi.2000, S.A. Marshall (4 ♀, DEBU); Puntarenas, Monteverde Biological Station, along upper trail, 10°18’7”N 84°48’10”W, 1700 m. 14–18.viii.2010, S.A. Marshall (5 ♂, DEBU); Puntarenas, Buenos Aires, Potrero Grande, Cerro Frantzins, 2134 m. 6–31.i.1997, Malaise, D. Rubi (1 ♂); Puntarenas, San Gerardo de Dota, Savegre Lodge, Canto de las Aves trail, 19–21.ii.2008, S.A. Marshall (1 ♂, 1 ♀). San José, Zurquí de Moravia, 1600 m. 10°3’N 84°1’W, 19.ii.2003, S.A. Marshall (1 ♀, DEBU); San José, Zurquí de Moravia, 1600 m. x–xii.1989, P. Hanson (1 ♂); San José, Moravia, Zurquí de Moravia, 1600 m. 5–9.viii.2013, hand collected at light, S.A. Marshall (2 ♂, 2 ♀, DEBU); San José, Zurquí de Moravia, 1600 m. 5–6.viii.2013, mix methods, S.A. Marshall (2 ♀, DEBU); San José, Moravia, Zurquí de Moravia, tower path, 1600 m. 20.x.2012, bait trap with human dung, canopy, project ZADBI (1 ♀); San José, Moravia, Zurquí de Moravia, north pasture, 1600 m. 15–22.iii.2013, Malaise, project ZADBI (1 ♀); San José, Moravia, Zurquí de Moravia, creek 2 north, 1600 m. 12.iv.2013, hand collected, project ZADBI (1 ♀); San José, Moravia, Zurquí de Moravia, creek 1, 1600 m. 24.ix. 2.x.2012, malaise, project ZADBI (1 ♀); San José, Moravia, Zurquí de Moravia, tower path, 1600 m. 30.iii. 6.iv.2013, malaise, project ZADBI (1 ♀); San José, Moravia, Zurquí de Moravia, tower path, 1600 m. 1–7.vi.2013, malaise trap, project ZADBI (1 ♀).

Etymology. The specific name is from the Latin for "pink", and refers to the rosy–hued abdominal pleuron of this distinctive species.

Comments: This is the only Central American Mesoconius with an almost entirely orange body, but color patterns, especially the black pigmentation on the frons, thorax and legs, are unusually variable in M. dianthus . Most obviously, the pale segments of the fore and hind tarsi range from white to yellow and the mid and hind tibia may or may not have a dark base, with some specimens lacking the black tibial bands altogether. Genitalic characters, however, seem to be consistent, and color variation does not seem to correspond with collection locality. Both male and female terminalia of M. dianthus suggest a close relationship to undescribed Andean species.

Several Mesoconius species seem to have converged on colors and structures resembling several species of common orange ichneumonids. Mesoconius dianthus is a striking mimic of ichneumonids in the genus Cryptopteryx , not only in colour but also in modification of the katatergite into a process resembling the sharp propodeal apophysis of the wasp. Cryptopteryx , like Mesoconius , is most diverse in the Andes (pers. com., Bernardo Santos).

Figures

FIGURE 2 A – J. Mesoconius dianthus. A, live male (Zurquí); B, a sympatric ichneumonid (Cryptopteryx sp.) with similar morphology (note the propodeal apophysis) and color. C, live female color variant with white tarsi and basal femoral band (Zurquí); D, head; E, spermatheca and associated structures, lateral; F, male terminalia; G, mating pair (Zurquí); H, wing; I, male abdomen, terminalia and abdominal apex; J, phallic bulb.