Mesoconius anchitarsus, Marshall, 2019

Marshall, Stephen A., 2019, A revision of the genus Mesoconius Enderlein (Diptera, Micropezidae, Taeniapterinae), European Journal of Taxonomy 548, pp. 1-126 : 19-22

Mesoconius anchitarsus sp. nov.

urn:lsid:zoobank.org:act:D73E5CA8-A4A6-4658-AF62-F33D00158249

Fig. 4

Etymology

The species name refers to the broad female fore tarsomere 1.

Material examined

Holotype

VENEZUELA • ♀; Mérida, Tabay, La Mucuy, Laguna Suero trail; 2700 m a.s.l.; 19 Jun.– 24 Jul. 1989; S. and J. Peck leg.; cloud forest; Malaise trap; MIZA.

Paratypes

VENEZUELA • 4 ♀♀, 1 ♂; same collecting data as for holotype; DEBU • 1 ♀; Trujillo, Bocono, road to Guaracamal ; 2130 m a.s.l.; 2 Mar. 1995; S.A. Marshall leg.; DEBU • 1 ♀; Merida, Rio Albarregas ; 2200 m a.s.l.; 24 Apr. 1988; S.A. Marshall leg.; cloud forest; DEBU .

Description

LENGTH. 17 mm.

COLOUR. Head mostly orange-brown, darker anteriorly; frontal vitta velvety dark brown anterior to ocellus, ocellar triangle and posterior part of vitta orange; antennae blackish microtrichose; clypeus, all of face below lunule and palpus yellow to orange; parafacial, gena (except small shiny midventral strip) and part of postocciput silver-microtrichose. Notum mostly orange, with two pairs of black vittae, outer vitta broader and interrupted by suture (vittae indistinct in male). Fore leg of male dark brown, except pale basal half of femur and pale distal part of tarsomere 1 and all of tarsomeres 2–5. Fore femur of female orange, fore tibia and tarsus black, tarsus with expanded and enlarged black tarsomere 1. Mid and hind femora of male dark brown to black, except for a broad and contrasting white band flanked by narrow reddish-brown zones and a reddish apex; female with brown mid and hind femora, broken by a white band at middle. Wing uniformly yellowish infuscated. Abdominal T3–6 pale and lightly sclerotized in females, sclerotized and brown like T1+ 2 in male; pleuron white.

HEAD. Epicephalon dull, contrasting with shiny paracephalon and orbital strips; frontal vitta slightly depressed, slightly tapered posterior to ocelli, slightly expanded anterior to ocelli with a narrow anteromedial point usually touching anterior margin of frons. One small fronto-orbital bristle inserted at level of anterior ocellus (on border between epicephalon and orbital strip). Upper face broadly raised, lunule prominent and setulose. Clypeus mostly bare, microtrichosity restricted to back corner. Subantennal area microtrichose.

THORAX. Cervical sclerite subshining, with a vertical groove separating a large subquadrate microtrichose posterior portion from a small bare anterior portion. Notum finely and densely microtrichose, acrostichal and dorsocentral setulae in indistinct rows. Postpronotal lobe sparsely microtrichose, with several scattered small pale setae, anterior and posterior margins flat. Dorsocentral bristle thin, longer than scutellar length. Scutellum with four small discal setulae and a pair of long, closely spaced apical bristles. Katatergite moderately prominent, with a small pointed apex. Notopleuron with two widely spaced black bristles. Vertical row of katepisternal bristles golden. Fore coxa with black anteroventral setae, mid and hind coxae with golden anteroventral setae. Fore tarsus of female with expanded and enlarged black tarsomere 1, twice as thick and as long as remaining tarsomeres. Male tarsomere 1 elongate, but no thicker than other tarsomeres. Mid and hind femora almost bare basal to white band, microtrichose and distinctly swollen distally.

ABDOMEN. Abdominal segments 1+2 petiolate, with almost no pleuron visible in male; female with T2 less petiolate. T1+2 about twice as long as T3; T1 setose, with preapical long, thin lateral setae; constricted area between T1 and T2 bare.

FEMALE ABDOMEN. Single spermatheca and duct vestigial, arising from side of a short, broad common duct shared with much broader and longer paired spermathecal duct, paired duct with a membranous basal ⅔ and a narrow, smooth distal third; stems of paired spermathecae convoluted, paired spermathecae pipe-shaped.

MALE ABDOMEN. Sternite 5 small; S6 large, unmodifed, broadest posteriorly. Synsternite 7–8 sparsely microtrichose, shiny, contrasting with dull, microtrichose preceding sclerites and microtrichose epandrium; S7 with a broad ventral part. Sternite 8 much smaller than epandrium; epandrium elongate, subquadrate, sparsely setose except densely long-setose produced posteroventral corner; cercus elongate oval, ventral part projecting. Basiphallus extending slightly beyond base of distiphallus. Basal part of distiphallus very short, narrow basally, gradually expanding to a broad, truncate and somewhat flattened apex enclosing base of phallic bulb; distal part of distiphallus very long and whip-like, extending beyond narrow anterior hypandrial margin. Ejaculatory apodeme greatly reduced, smaller than associated sperm pump.

Remarks

Mesoconius anchitarsus sp. nov. is very similar to M. albitergum sp. nov. ( Colombia) and M. cosanga sp. nov. ( Ecuador), with almost the same thoracic and leg pigmentation and very similar internal genitalia. The females of M. anchitarsus sp. nov., however, are strikingly different because of their greatly enlarged and flattened first fore tarsomere. The only available male specimen of M. anchitarsus sp. nov. differs from males of M. albitergum sp. nov. in having darkly pigmented and sclerotized T3–6.

Figures

Fig. 4. Mesoconius anchitarsus sp. nov. A. Thorax-abdomen junction to show prominent katatergite (indicated by arrow). B. Paratype ♂. C. ♀. D. Spermatheca and associated structures. E. Male terminalia. F. Head, ♀. G. Head, ♂. Abbreviations: b = basiphallus; bdp = basal distiphallus; c = cercus; ddp = distal distiphallus; e = epandrium; pb = phallic bulb.