Mesoconius auristrigatus Enderlein, 1922

Marshall, Stephen A., 2019, A revision of the genus Mesoconius Enderlein (Diptera, Micropezidae, Taeniapterinae), European Journal of Taxonomy 548, pp. 1-126 : 22-25

Mesoconius auristrigatus Enderlein, 1922

Figs 5–6

Mesoconius auristrigatus Enderlein, 1922: 178 .

Material examined

Holotype

COLOMBIA • ♀; v. Nolcken leg.; MNBG.

The collector was presumably J.H. Wilhelm Baron (von) Nolcken, who collected in the mountains of Colombia during 1870–71 ( Papavero 1973).

Other material

COLOMBIA • 1 ♀; Huila, PNN Cueva de los Guácharos Mirador ; 01°38ʹ N, 76°06ʹ W; 1980 m a.s.l.; 2–5 Dec. 2001; D. Campos leg.; Malaise trap 4; MYCRO325-18 sequenced for CO1; IAVH .

ECUADOR • 1 ♂; Napo, SierrAzul Lodge , 14 km W of Cosanga; 2200 m a.s.l.; 8–11 May 2002; S.M. Paiero leg.; dung on leaf; MYCRO455-18 sequenced for CO1; DEBU • 2 ♀♀; Pichincha, 15 km NW of Nono, road to Mindo ; 2000 m a.s.l.; 25 Oct. 1999; S.A. Marshall leg.; on log; DEBU • 1 ♀; Pichincha, Bellavista Reserve ; 2200 m a.s.l.; 28 Oct. 1999; S.A. Marshall leg.; DEBU • 2 ♀♀; Pichincha, Mindo, trail to Bellavista Reserve ; 00°03ʹ29ʺ S, 78°46ʹ06ʺ W; 1 May 2011; S.A. Marshall leg.; DEBU • 4 ♀♀; Pichincha, Bellavista Cloud Forest Reserve ; 00°01ʹ13ʺ S, 78°40ʹ30ʺ W; 2200 m a.s.l.; 9–13 May 2009; S.A. Marshall leg.; MYCRO080-15 sequenced for CO1; DEBU .

Redescription

LENGTH. 17–18 mm.

COLOUR. Head black, except as follows: parafacial, postgena and most of gena silvery microtrichose, middle part of gena shiny brown ventrally; palpus yellow-orange; lower face pale, face and clypeus otherwise brown. Thorax mostly dark brown to black, with reddish patches, notum dull brown, except for indistinct subshining black patch above postpronotal lobe, prominent narrow golden dorsocentral vitta and a wider postsutural vitta running over supra-alar area to side of scutellum; posterior notopleural bristle arising from a microtrichose patch; pleuron with large silvery patches posteroventrally on katepisternum and posteriorly on anepisternum; most of propleuron, cervical sclerite and prominent katatergite orange. Fore leg orange basally, apex of femur, tibiae and tarsus black, mid and hind femora orange, except for a variably brown- or black-margined middle white band (in some specimens white band only margined distally). Wing uniformly infuscated, without clear spots or bands. Abdomen with tergites reddish and pleuron pale on segments 1–3; tergites brown and pleuron darkened on segments 4–6. Oviscape pale brown, darker at apex.

HEAD. Epicephalon and paracephalon very finely striate, dull; frontal vitta sharply tapered posterior to ocelli, broad anterior to ocelli, with an inconspicuous anteromedial point, widely separated from anterior margin of frons; inner vertical bristle strong, with four–five setulae near base. One strong fronto-orbital bristle inserted in a discrete patch of thick white microtrichia near lower margin of epicephalon. Upper face broadly raised, microtrichosity of lower face extending dorsally as a parallel-sided band almost to lunule, subantennal areas mostly shiny, lower corner microtrichose.

THORAX. Cervical sclerite with a vertical groove separating a large subquadrate posterior portion from a small anterior portion. Notum finely and densely microtrichose, acrostichal and dorsocentral setulae in distinct rows, scattered setulae also present anterolaterally. Postpronotal lobe dull, densely microtrichose with several scattered small pale setae, anterior margin bare, shiny and almost vertical, posterior margin bare and sloped. Notopleuron with two widely spaced bristles, posterior bristle darker and thicker than anterior. Dorsocentral bristle very small, golden, shorter than scutellar length and about ⅓ as long as golden supra-alar. Scutellum with four small discal setulae and a pair of long, closely spaced black apical bristles (longer than scutellum). Katatergite very prominent, with a long, nipple-like microtrichose pointed process. Vertical row of katepisternal bristles golden. All coxae with golden anteroventral setae.

ABDOMEN. Abdominal segment 1 and basal half of segment 2 petiolate; length of 1+2 slightly less than double length of tergite 3. T1 setose, with preapical long, thin lateral setae.

FEMALE ABDOMEN. Oviscape bare, except for scattered setulae. Bursa small, suboval, ventral receptacle small and inconspicuous. Single spermathecal duct constricted at base, branching off a very short common duct that then tapers slightly to much longer paired spermathecal duct, which is divided into distinct parts including a short rugose basal ⅓ that abruptly transforms into a slightly narrower, relatively smooth (indistinctly striate) distal ⅔. Paired spermathecae expanded distally, apex invaginated, surface reticulate, stem (beyond division of paired duct) broad, conspicuously coiled and finely tuberculate on basal half, distal half dark, thick and very strongly tuberculate. Single spermathecal duct similar in texture to distal part of paired spermathecal duct but much smaller, single spermatheca small, on a thick tuberculate stem as thick as spermatheca, separated from main part of duct by a constriction.

MALE ABDOMEN (tentative association; see Remarks). Sternites 5and 6large, tapered anteriorly and notched posteromedially. Synsternite 7–8 sparsely microtrichose, shiny, contrasting with dull, microtrichose preceding sclerites and pale microtrichose epandrium; S7 with a very broad but unmodified ventral part. Sternite 8 much smaller than epandrium, epandrium elongate, sparsely setose except for a dense patch of setae posteroventrally; cercus prominent, large, elongate and slightly curved, strongly projecting posteroventrally. Hypandrium elongate and slender, extending to anterior margin of T6. Basiphallus small, not extending beyond base of distiphallus. Basal part of distiphallus narrow basally, distally abruptly expanding to enclose a small phallic bulb; distal part of distiphallus tapered and whip-like. Ejaculatory apodeme very small, smaller than attached sperm pump.

Remarks

Mesoconius auristrigatus seems to be very closely related to M. nigripleuron sp. nov. (from Peru). Male specimens assigned to these two species are similar, but those of M. nigripleuron sp. nov. have apically concave or bilobed cerci, in contrast to the tapered cerci of the one male treated as M. auristrigatus . These species also differ in leg colour and spermathecal structure, and they are widely separated (p-distance ca 10%) on the CO1 tree ( Fig. 50 ). Ecuadorian and Colombian female specimens treated here as M. auristrigatus have distinct CO1 sequences and differ slightly in the colour of the margins of the bands on mid and hind tibia. Examination of more extensive collections might justify recognition of the Ecuadorian populations as a separate species and might show that the Ecuadorian populations on the eastern side of the Central Valley (now known from one male) and western side of the Central Valley (now known only from females) differ. See also Remarks under M. noteques sp. nov.

Figures

Fig. 5. Mesoconius auristrigatus Enderlein, 1922, external characters. A, C. Living ♀♀, Ecuador. B. Head, ♀. D. Holotype, ♀, MNBG. E. Pleuron and base of abdomen to show orange katatergite.

Fig. 6. Mesoconius auristrigatus Enderlein, 1922, internal characters. A. Male epandrium and cerci, posterodorsal view. B. Spermathecae and associated structures. C. Male terminalia with phallus teased out, directed ventrally. D. Apex of abdomen, ♂, lateral view. Abbreviations: c = cercus; ddp = distal distiphallus; e = epandrium; hy = hypandrium; pb = phallic bulb.

Fig. 50. Maximum likelihood tree from CO1 barcodes. Sequences were aligned using BOLD (amino acid based HMM) and then manually corrected. Maximum likelihood analysis was performed in RAxML (ver. 8.2) using GTR-G with 100 replicates.