Mesoconius Enderlein, 1922

Marshall, Stephen A., 2019, A revision of the genus Mesoconius Enderlein (Diptera, Micropezidae, Taeniapterinae), European Journal of Taxonomy 548, pp. 1-126 : 4-12

Mesoconius Enderlein, 1922

Mesoconius Enderlein, 1922: 176 (type species: Mesoconius infestus Enderlein, 1922 ).

Zelatractodes Enderlein, 1922: 169 (type species: Zelatractodes filipes Enderlein, 1922 ) (synonymized in Marshall 2015).

Aristobata Frey, 1927: 69 (type species: Aristobata melini Frey, 1927 = Zelatractodes filipes Enderlein, 1922 ) (synonymized in Steyskal 1968).

Description

Length 11–21 mm. Colour variable between, and often within, species.

HEAD. Arista bare. Fronto-orbital bristles weak to strong, in one–two pairs with upper pair (if present) at or above level of upper ocelli, lower pair below level of lower ocellus near overlap between epicephalon and orbital plate. Postocellar and outer vertical bristles present or absent, inner vertical bristles always present, although sometimes very small. Lower frons usually elevated, forming a transverse, slightly scooped band in front of frontal vitta; frontal vitta usually broad and diamond- or teardrop-shaped and slightly elevated in front of ocelli but shape, elevation and extent variable. Face pale and weakly sclerotized on ventral third to half, broadly elevated to narrowly carinate dorsally; frons usually separated from antennal socket, exposing a suprantennal shelf or antennal base between antenna and lower margin of frontal plate. Clypeus shiny medially, microtrichose laterally or posterolaterally, normally slightly angled forward on pinned specimens. Palpus parallel-sided or nearly so, usually broad.

THORAX. Cervical sclerite usually with a swollen microtrichose posterior section sometimes (females only) with a whitish or dull posterior patch of sensillae; anterior section depressed, flat, bare and sometimes divided by a carina. Prosternum on two planes, anterior part depressed and narrow, posterior (main) part usually broad (narrow in M. bipleuron sp. nov.), usually microtrichose, often setose, rarely bare. Pronotum microtrichose, except for narrow anterolateral lobe. Scutum with two notopleural bristles and one posterior (prescutellar) dorsocentral bristle (rarely absent); scutellum usually with a few discal setulae and a single pair of long apical bristles (absent in M. garyi sp. nov. only). One or more fore tarsomeres of one or both sexes sometimes enlarged and flattened. Fore tibia longitudinally grooved, often inconspicuously so but sometimes strongly flattened and conspicuously sulcate on posterior face. Mid and hind femora densely microtrichose distally, bare or almost bare and shiny basally; hind femur usually at least slightly swollen distally. Katatergite usually at least slightly swollen, often very prominent with a nipple-like central process. Dorsocentral bristles in a single posterior pair, often reduced, rarely absent. Wing variable in colour, but usually darkened at least in distal half and often with an indistinct preapical clear area that is partially or completely divided into patches; some species with clear, uniformly pigmented or distinctly banded wing. Third costal sector (between R 2+3 and R 4+5) short, much less than half as long as second costal sector. Anal cell short, with a strong longitudinal crease or false vein in basal third. Costagial bristle relatively short, extending approximately to humeral crossvein.

ABDOMEN. Usually distinctly petiolate, with syntergite 1+2 elongate and pleuron of at least segment one reduced, rendering the base of the abdomen conspicuously slender (the closely related M. nigra sp. nov., M. quadritheca sp. nov. and M. ruficrus sp. nov. are exceptions, with only the basal portion of segment 1 constricted).

FEMALE ABDOMEN. Oviscape short and stout, with upper and lower surfaces fused to form a cylinder, usually directed posteriorly or ventrally, rather than strongly deflexed anteriorly as in many Taeniapterinae . Spermathecae (1+2, rarely 2+2) and associated ducts typically complex and often species-specific, usually with a distinct ventral receptacle on a broad bursa. In most species a relatively thick duct (paired spermathecal duct) leads to paired spermathecae, each of which is on a frequently elaborately sculptured or swollen stem; a smaller duct (single spermathecal duct) leads to a single (or rarely a pair of) small spermatheca(e). Spermathecal ducts either arise independently from apex of bursa or from a short or long common duct before splitting into paired and single ducts.

MALE ABDOMEN. Male S5 small to entirely reduced, S6 elongate to greatly reduced, often expanded posteriorly; S8 usually large and often different in colour and texture from preceding tergites and from epandrium; epandrium small to very small; ejaculatory apodeme variable in size. Hypandrium forming a short to long loop anteriorly (anterior margin either belt-like, scoop-like, or broad and twisted), posteriorly articulating with long anteroventral epandrial extensions and extending medially into a robust and microtrichose phallic plate. Postgonite small and inconspicuous, but apically broad, with small apical or preapical setae, basiphallus usually small and frame-like, but sometimes extended well beyond base of distiphallus; distiphallus divided into a broad basal part, a prominent phallic bulb, and (usually) a variously developed distal part.

Keys to the South American species of Mesoconius Enderlein, 1922

Some species of Mesoconius are sexually dimorphic for colour, and most show intraspecific variation in the conspicuous colour characters traditionally used to distinguish species. This infraspecific colour variation, combined with a very high level of local endemism, often made it difficult to match the limited fresh material to older names. Many species remain known only from single specimens taken at type localities that have not been practical to re-sample, such as Thiele’s collection localities in the Colombian Andes and the infamous late 19 th century Peruvian collection locality of “Callanga” ( Woytkowski 1974). For several of the species known only from older type specimens, genitalic characters are unavailable and chaetotaxy can only be inferred. Inclusion of these species in the keys demands the use of colour as a key character, despite intraspecific variability in pigmentation patterns.

Key one: general key and key to species of the Mesoconius infestus group

1. Katatergite almost always swollen ( Fig. 5E ), usually conspicuously swollen with a nipple-like apex ( Fig. 9E ); exceptions (three species of the M. eques group with an indistinctly swollen katatergite) lack postocellar bristles ( Fig. 5B ). Outer vertical bristle absent ( Fig. 5B )..................2

– Katatergite weakly swollen and gently rounded, without a nipple-like apex ( Fig. 38D ); postocellar bristle always present. Outer vertical bristle present or absent ...........................Key three

2. Mid and hind legs uniformly orange, without bands; body entirely black to very dark brown, notum with indistinct silvery vitta ( Fig. 23A ). Wing brown, with three small clear spots distally ........................................................... Mesoconius flavipes Enderlein, 1922 ( Colombia)

– If legs uniformly orange, then body also entirely or partly orange. Wing and notum variable....3

3. Postocellar bristle absent, upper back of head thus with only inner vertical bristle ( Fig. 3F ). Stems of paired spermathecae conspicuously multi-branched and/or spermathecal ducts sharing a common stem well beyond apex of bursa ( Fig. 3C ). Hypandrium anteriorly narrow and ribbon-like ( Fig. 6D ) .......................... Mesoconius eques group ..........................Key two

– Postocellar and inner vertical bristles present. Stems of paired spermathecae sometimes swollen but not branched or tuberculate. Spermathecal ducts arising separately from a short distal extension of bursa ( Fig. 27C ). Hypandrium anteriorly very broad and conspicuously twisted ( Fig. 21B ) ..................................... Mesoconius infestus group.....................................4

4. Thorax black or dark brown, at least dorsally..............................................................................5 – Thorax orange ....................................................................................................................................9

5. Hind tibia black and posteroventral part of pleuron, mid coxa and hind coxa orange.........6 – Hind tibia yellow or orange. Pleuron and coxae black.............................................................7

6. Katepisternum and part of abdominal T1 orange or red ( Fig. 22H ). Oviscape bare, shiny .............. ................................................. Mesoconius albimanus Enderlein, 1922 ( Peru, Colombia, Bolivia)

– Katepisternum and abdominal T1 black ( Fig. 22G ). Oviscape largely setulose ................................. .......................................................................................... Mesoconius albipedis sp. nov. ( Colombia)

7. Fore tarsus white, contrasting with bright yellow hind tarsomeres 1 and 2 ( Fig. 27A ). Hind femur black, except for orange apex ................................................... Mesoconius notacca sp. nov. ( Peru)

– Fore tarsus yellow, similar in colour to hind tarsomeres 1 and 2. Hind femur orange with black bands ..................................................................................................................................................8

8. Sternite 8 of male (the dorsal sclerite immediately anterior to the epandrium) mostly microtrichose, shiny only on anterior quarter ( Fig. 21A ). Frontal vitta more or less diamond-shaped ( Fig. 20B ). Length about 20 mm .................................................... Mesoconius acca sp. nov. ( Peru)

– Sternite 8 of male entirely bare and shiny ( Fig. 24B ). Frontal vitta teardrop-shaped ( Fig. 24E ). Length less than 19 mm .................................................................... Mesoconius infestus Enderlein, 1922 ( Bolivia, Colombia, Ecuador) (possibly a species complex; highly variable in leg colour)

9. Head black ................................................ Mesoconius nigricephala sp. nov. ( Ecuador, Colombia) – Head orange .....................................................................................................................................10

10. Mid and hind femora entirely orange ( Fig. 23C ) ...... Mesoconius fulvus Enderlein, 1922 ( Ecuador) – Mid and hind femora with broad black bands at midlength ( Fig. 23D ).................................11

11. Fore tibia black, except for extreme apex. Frontal vitta rounded anteriorly, not sharply demarcated from lower frons ( Fig. 29D ) ........... Mesoconius ujhelyianus Enderlein, 1922 ( Colombia, Ecuador)

– Fore tibia yellow-brown. Frontal vitta distinctly triangular, upper margin tapered, and lower margin straight and forming a sharp line of demarcation between the black frontal vitta and the yellow lower frons ( Fig. 23F ) ....................... Mesoconius garleppi Enderlein, 1922 ( Peru)

Key two: the Mesoconius eques group (outer vertical and postocellar bristles absent)

1. Katatergite conspicuously swollen, with a prominent nipple-like apex ( Fig. 16B ).....................2 – Katatergite at most slightly swollen, without a prominent nipple-like apex ( Fig. 18D )............14

2. Mid and hind leg entirely or almost entirely black, femora sometimes with narrow pale rings or with narrow reddish basal and distal parts. Body colour black or blue-black; hind tarsus never white ...................................................................................................................................................3

– No leg entirely or almost entirely black. Body colour variable, if black then hind tarsus white......5

3. Fore tarsus mostly white, first tarsomere not enlarged ( Fig. 15A ) ....................................................... ............................................................................................ Mesoconius pasachoa sp. nov. ( Ecuador)

– Fore tarsus black, first tarsomere sometimes enlarged.....................................................................4

4. First tarsomere of fore leg of both sexes enlarged, broad and flat ( Fig. 9B ). Mid coxa with comb of black anteroventral bristles. White bands on hind femur usually distinct ...................... ................................................................. Mesoconius eques ( Schiner, 1868) ( Ecuador, Venezuela)

– First tarsomere of females slender ( Fig. 13C ), males unknown. Mid coxa with comb of golden anteroventral bristles. Bands on mid and hind femora indistict to obsolete ................................... ................................................................................................. Mesoconius noteques sp. nov. ( Peru)

5. Thorax entirely or mostly yellow or orange......................................................................................6 – Thorax entirely or mostly black or very dark brown........................................................................9

6. Thorax, base of abdomen and basal third of mid and hind femora orange to red, without vittae. Abdominal pleuron with black vertical stripes; tergites black ( Fig. 17A ) .......................................... ............................................................... Mesoconius rufithorax Enderlein, 1922 ( Peru and Bolivia)

– Thorax colour not totally orange to red, notum distinctly vittate. Abdominal pleuron unmarked; tergites 3–6 usually pale or desclerotized...........................................................................................7

7. Fore tarsus (of females and known males) unmodified. Abdomen of males white, tergites pale and lightly sclerotized (males of M. cosanga sp. nov. unknown).................8

– Fore tarsomere 1 of female greatly enlarged, wider and longer than remainder of tarsus ( Fig. 4C ). Abdomen of male dark, tergites sclerotized .............. Mesoconius anchitarsus sp. nov. ( Venezuela)

8. Fore tarsus black. Notum with broad black vittae. Ocellar triangle elevated, orange ( Fig. 3F ) .. ..................................................................................... Mesoconius albitergum sp. nov. ( Colombia)

– Fore tarsus white. Notum orange, with narrow golden vittae interrupted by suture ( Fig. 7C ). Ocellar triangle not elevated, mostly black ( Fig. 7A ) .......... Mesoconius cosanga sp. nov. ( Ecuador)

9. Mid and hind femora with a pale yellow or orange band at middle, sometimes margined with darker bands....................................................................................................................................10

– Mid and hind femora without a pale band, instead either bicoloured, concolourous reddish or with darker bands ......................................................................................................................…12

10. Fore tarsus mostly yellow (base of basal tarsomere black). Mid and hind femora reddish brown, with an inconspicuous pale middle band. Abdominal pleuron pink, tergites and oviscape mostly orange ( Fig. 16E ) ......................... Mesoconius rufipleuron sp. nov. ( Ecuador)

– Fore tarsus entirely black. Mid and hind femora orange or yellow, with a pale yellow band at middle. Abdomen darker, differently pigmented, usually part black and part yellow..................11

11. Males with cercus tapered and simple ( Fig. 6A ). Notum with two presutural and four postsutural narrow golden longitudinal vittae; katatergite prominent and orange, in contrast with otherwise mostly dark mesopleuron ( Fig. 5E ). Black preapical bands on mid and hind femora weak and narrow ( Fig. 5A ) ........................... Mesoconius auristrigatus Enderlein, 1922 ( Ecuador, Colombia)

– Males with cercus bilobed ( Fig. 12E ). Notum with a broad median black strip flanked by broad lateral golden vittae; katatergite not contrasting with surrounding mesopleuron. Black preapical bands on mid and hind femora broad and strong ( Fig. 11D ) ................................................................ ................................................................... Mesoconius nigripleuron sp. nov., in part ( Peru, Bolivia)

12. Katatergite orange. Mid and hind femora entirely red-orange exept for a narrow black base. Mid and hind tibiae orange ( Fig. 10A ) ........................... Mesoconius hirsutimamma sp. nov. ( Colombia)

– Katatergite dark. Mid and hind femora yellow-red at least distally, usually with black rings or black base. Tibiae yellow to brown................................................................................................13

13. Frontal vitta with a tapered point reaching anterior margin of frons and with lateral extensions almost reaching eye. Epandrium with a pointed tuft of densely packed setae at posteroventral corner ( Fig. 8C ). Female abdominal pleuron pale ..... Mesoconius epandribarba sp. nov. ( Colombia)

– Frontal vitta broadly rounded anteriorly, widely separated from both frons margin and eye. Epandrium without a pointed tuft of densely packed setae at posteroventral corner ( Fig. 12A ). Female abdominal pleuron darkly pigmented ( Fig. 11A ) ... Mesoconius nigripleuron sp. nov., in part ( Peru)

14. Hind femur orange on basal half and black on distal third, with a yellow or white ring between black and orange parts; mid femur basally orange, distally black ( Fig. 14F ). Tergites 1–3 orange, distal tergites black. Males unknown. ... Mesoconius obtusiconus Enderlein, 1922 ( Peru, Colombia)

– Mid and hind femora black with orange apices and a white central band, or femora orange with a black band near middle. Tergites uniformly coloured or darkest near base of abdomen............15

15. Mid and hind femora black with orange apices and a white central band. Male fore tarsus black, distal tarsomeres greatly enlarged ( Fig. 1B ). Female fore tarsus white basally and black distally ( Fig. 1C ). Body mostly black. Male S5 and S6 elongate, well developed. Wing uniformly pigmented ............................................................................. Mesoconius albiseta sp. nov. ( Ecuador)

– Mid and hind femora orange with brown rings ( Fig. 19 ), basal two thirds of hind femur sometimes more extensively pigmented. Fore tarsus entirely white, male fore tarsus with apex of tarsomere 1 curved to meet an enlarged tarsomere two Fig. 19D ). Body usually mostly orange. Sternite 5 of male greatly reduced, S6 reduced to two widely separated sclerites ( Fig. 18E ). Males with wing clear, except for a dark apical spot ( Fig. 19D ), female wing uniformly yellowishclear ................................................................................ Mesoconius suzukii sp. nov. ( Colombia)

Key three: the Mesoconius oblitus and nono groups

Species with a postocellar bristle but without a swollen katepisternum will key out here. These species are divided into the ʻ M. nono groupʼ (with an outer vertical bristle) and the ʻ M. oblitus groupʼ (without an outer vertical bristle), but the vertical bristles are often broken and can be difficult to assess. Both groups are infrequently collected, and most species are known from either a single sex, a single specimen, or from inadequate older type specimens.

1. Thorax orange to reddish brown; head entirely black.....................................................................2

– Thorax usually dark brown or black, but if orange then head similarly coloured at least on posterior half .....................................................................................................................................................6

2. Wing mostly clear, with a broad and distinct but incomplete dark discal band ( Fig. 36A ). Anterior spiracle black .................................................. Mesoconius uchumachi sp. nov. ( Bolivia)

– Wing either uniformly pigmented, uniformly clear, or infuscated with one–three clear areas distally. Anterior spiracle orange to reddish brown...........................................................................3

3. Mid and hind femora with a white ring near the middle...............................................................4 – Mid and hind femora uniformly pigmented or black distally, without a white ring....................5

4. Basal half of mid and hind femora orange to brown, darker adjacent to white distomedian ring; distal part beyond white ring black, broad and sulcate ( Fig. 30E ) ...................................................... .................................................................................... Mesoconius scurrus ( Hennig, 1935) ( Bolivia)

– Mid and hind femora brown, except for broad white ring near middle; distal part of hind femora neither strongly swollen nor sulcate ( Fig. 40G ) .................................................................................. ................................................... Mesoconius versicolorus ( Enderlein, 1922) ( Colombia, Venezuela)

5. Prothorax black. Hind femur sharply bicoloured, distal half black ( Fig. 40E ) ................................... ........................................................................................ Mesoconius filipes ( Enderlein, 1922) ( Peru)

– Prothorax brown, similar to mesothorax. Hind femur uniformly brown in typical specimens ( Fig. 40C ) ............................................................... Mesoconius cyclops ( Hennig, 1935) ( Bolivia)

6. Thorax orange....................................................................................................................................7 – Thorax dark .....................................................................................................................................12

7. Mid and/or hind femora with basal or distomedian black rings ( Figs 33A , 38A ). Frontal vitta black ( Fig. 38C ). Outer vertical bristle present or absent................................................................8

– Mid and hind femora uniformly pigmented. Frontal vitta orange ( Fig. 31A ). Outer vertical bristle present ( Fig. 31A )...........................................................................................................................11

8. Scutellum with a pair of long apical bristles ( Fig. 38B ). Postpronotal lobe orange. Frontal vitta black, but not extending to anterior margin of frons, or entire lower frons black; flat to strongly convex ................................................................................................................................................9

– Scutellum without apical or other bristles. Thorax with a distinct black spot over postpronotal lobe ( Fig. 33A ). Frontal vitta flat, black, elongate-triangular and reaching or almost reaching anterior margin of an otherwise reddish frons ( Fig. 33F ) ........... Mesoconius garyi sp. nov. ( Peru)

9. Mid and hind femora with distomedian rings. Fore tarsomere 1 mostly black. Frontal vitta strongly convex or lower frons black.............................................................................................10

– Hind femur with basal black ring, mid femur uniformly orange. Fore tarsus entirely yellow. Frontal vitta almost flat, black, widely separated from anterior margin of frons, lower frons orange ( Fig. 30C ) ..........................................................................................… Mesoconius ottoi (new replacement name for M. garleppi ( Enderlein, 1922) ; Bolivia and perhaps Colombia)

10. Outer vertical bristle present ( Fig. 38C ). Wing uniformly infuscated. Lower frons entirely black, concolourous with frontal vitta and contrasting with yellow face and antennal bases ( Fig. 38C ). Fore tarsus black distally. Hind femur with two black rings ..... Mesoconius zorro sp. nov. ( Peru)

– Outer vertical bristle absent. Wing with distal clear areas ( Fig. 40B ). Anterior margin of frontal vitta separated from frons margin by pale area. Fore tarsus white distally. Hind femur with a single incomplete ring ...................... Mesoconius braueri ( Hennig, 1935) ( Venezuela)

11. Mid and hind femora uniformly brown ( Fig. 30A ). Fore tarsus and tibia similarly pale brown ... ............................................................................. Mesoconius hoffmannsi ( Enderlein, 1922) ( Peru)

– Mid and hind femora uniformly orange ( Fig. 31A ). Fore tarsomeres 2–5 white, contrasting with black fore tibia and base of tarsomere 1 ............................... Mesoconius aurantium sp. nov. ( Peru)

12. Outer vertical bristle absent ( Fig. 48B ).......................................................................................13 – Outer vertical bristle present ( Fig. 37B ).......................................................................................25

13. Frons sharply bicoloured: lower frons, face and antennae orange to yellow, remainder of head black. Fore tarsomere 1 expanded, strongly and conspicuously so in male ( Fig. 43C ). Hind femur dark, with a reddish distomedian ring ........................ Mesoconius lobopoda sp. nov. ( Colombia)

– Lower frons dark, not sharply contrasting with upper frons. Fore tarsomere 1 similar in diameter to tibia, not strongly flattened in either sex. Hind femur without a reddish distomedian ring.........14

14. Face and lunule yellow ( Fig. 42A ). Frontal vitta broadly reaching frontal margin. Mid and hind femora with broad basal and distal black bands, similar in length to intervening middle orange band ( Fig. 41D )................................................................................................................................15

– Face and lunule at least partially dark. Frontal vitta tapered, reaching frontal margin at most as a point. Femoral colour variable.....................................................................................................16

15. Mid and hind femoral apices orange ( Fig. 41D ). Postocellar portion of frontal vitta tapered to a narrow point; parafacial orange ( Fig. 41E ). Oviscape orange ............................................................. ............................................................................................... Mesoconius apicalis sp. nov. ( Ecuador)

– Mid and hind femoral apices black ( Fig. 42B ). Postocellar portion of frontal vitta broad; parafacial black ( Fig. 42A ). Oviscape black .................. Mesoconius gelbifacies sp. nov. ( Ecuador)

16. Hind femur with a broad distomedian pale ring ( Fig. 45B )......................................................18 – Hind femur with at most a narrow distomedian pale ring............................................................21

18. Frontal vitta strongly convex and dome-like ( Fig. 45E ). Epicephalon microtrichose .......................... ..................................... Mesoconius oblitus ( Hennig, 1935) species complex ( Venezuela, Colombia) – Frontal vitta at most slightly convex, not dome-like. Epicephalon shiny....................................19

19. Body dark metallic blue ( Fig. 48A ). Mid and hind femora black with white bases and white distomedian rings. Fore and hind tarsi black ........................... Mesoconius rex sp. nov. ( Colombia) – Body black to dark brown. Femora without white basal rings. Fore and/or hind tarsi all or mostly white .................................................................................................................................................20

20. Hind femur with pale ring between basal yellow half and distal brown third; mid femur darkened in distal third but without pale ring ( Fig. 40A ) ............................................................... ........................................................................... Mesoconius afurcatus ( Hennig, 1935) ( Venezuela)

– Mid and hind femur dark basally and distally and with a broad pale ring at middle ( Fig. 42E ) .. .................................................................................................. Mesoconius keili sp. nov. ( Ecuador)

21. Abdomen all or mostly reddish or orange. Mid and hind femora orange, with or without darker rings .................................................................................................................................................22

– Abdomen all or mostly black or metallic blue-black. Mid and hind femora mostly black, sometimes with paler rings.....................................................................................................................23

22. Mid and hind femora orange with indistinct distomedian rings. Scutellum brown. Wing lightly infuscated, with clear distal areas ( Fig. 40F ) .. Mesoconius rufiventris ( Enderlein, 1922) ( Colombia)

– Mid and hind femora orange, without distomedian rings. Scutellum orange. Wing heavily and evenly infuscated, yellow, without clear distal areas ( Fig. 49D ) ...... Mesoconius ruficrus sp. nov. ( Peru)

23. Hind femur with an indistinct reddish mediodistal ring, femora otherwise black. Wing with clear distal patches ( Fig. 41A ) ............................................................. Mesoconius apa sp. nov. ( Bolivia)

– Mid and hind femur with white distomedian ring. Wing darkly infuscated, without clear patches ..........................................................................................................................................24

24. Inner vertical and postocellar bristles greatly reduced, barely distinguishable from surrounding setulae ( Fig. 47A ) ................................................................ Mesoconius quadritheca sp. nov. ( Peru)

– Inner vertical and postocellar bristles large, distinct ( Fig. 44A ) ..................................................... .................................................................................................. Mesoconius nigra sp. nov. ( Bolivia)

25. Thorax sharply bicoloured: notum black, balance of thorax entirely yellow ( Fig. 37A ). First abdominal tergite and base of T2 entirely yellow to orange, abdomen otherwise black ................... .............................................................................................. Mesoconius wytkowskii sp. nov. ( Peru)

– Neither thorax nor abdomen sharply bicoloured...........................................................................26

26. Thorax and abdomen entirely black or metallic blue...............................................................27 – Thorax partially black, but with orange or reddish-brown patches at least on pleuron; abdominal tergites orange (females) or brown (males) ( Fig. 32 ) .... Mesoconius bipleuron sp. nov. ( Colombia)

27. Thorax and abdomen black, notum silvery microtrichose, except for broad central strip ( Fig. 34A ). Legs variable in colour, but hind femora either uniform in colour or with basal half dark. Abdominal pleuron dark ...................................................... Mesoconius nono sp. nov. ( Ecuador)

– Thorax and abdominal tergites metallic blue with light pruinosity. Mid and hind femora black, with broad white distomedian bands ( Fig. 35A ). Abdominal pleuron white, except for upper part of P2 ......................................................................... Mesoconius reinai sp. nov. ( Colombia)

Species descriptions

The species treatments below are in alphabetical order within each of four groups: the M. eques group, the M. infestus group, the M. nono group and the M. oblitus group. The latter two, loosely equivalent to ʻ Zelatractodes ʼ of previous authors, are weakly supported groups diagnosed on the presence ( M. nono group) or absence ( M. oblitus group) of outer vertical bristles. Species descriptions are prefaced with a brief summary of readily visible colour characters, followed by descriptions of the head, thorax and abdomen. Previously described species known only from undissected type material are briefly diagnosed rather than redescribed. Previously described species known from undissected type material as well as dissected non-type material are redescribed based in part on the dissected non-type material.

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. 9. Mesoconius eques (Schiner, 1868). A. Presumed holotype, ♂, NHMW, Venezuela. B. Live ♂, Ecuador. C. Head. D. ♀ (right) and a sympatric undescribed species of Poecilotylus Hennig, 1934 (left), Ecuador. E. Thorax-abdomen junction to show prominent katatergite. F. Base of phallus and distal part of phallapodeme, Ecuador. G. Abdomen, ♂, lateral view, Ecuador. H. Spermatheca and associated structures, Ecuador. I. Male aedeagus and associated structures, Ecuador. Abbreviations: bdp = basal distiphallus; cd = common spermathecal duct/distal bursa; ddp = distal distiphallus; ea = ejaculatory apodeme; ed = ejaculatory duct; hy = hypandrium; pb = phallic bulb; pd = paired spermathecal duct; ph = phallapodeme; pss = paired spermathecal stem; sd = single spermathecal duct.

Fig. 38. Mesoconius zorro sp. nov., external characters. A. Paratype prior to capture, ♀, DEBU. B. ♂ prior to capture. C. Head. D. Posterior thorax and base of abdomen.

Fig. 23. A–B. Mesoconius flavipes Enderlein, 1922, holotype, ♂, MNBG. — C. M. fulvus Enderlein, 1922, holotype, ♂, MNBG. — D–F. M. garleppi Enderlein, 1922, holotype, ♂, MNBG.

Fig.3.Mesoconiusalbitergumsp.nov.A.♀.B.Holotype,♂,IAVH.C.Spermathecaandassociatedstructures. D. Abdominal apex, ♂, lateral view. E. Male terminalia, lateral view but with phallus twisted (basiphallus 90° left, distiphallus 180°). F. Head and thorax, ♀. Abbreviations: b = basiphallus; bc = bursa copulatrix; bdp = basal distiphallus; c = cercus; ddp = distal distiphallus; e = epandrium; iv = inner vertical bristle; pb = phallic bulb; pd = paired spermathecal duct; pst = paired spermathecal duct; sd = single spermathecal duct; ss = single spermatheca.

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. 27. Mesoconius notacca sp. nov. A. Paratype prior to capture, ♀, DEBU. B. Head and anterior thorax. C. Spermathecae and associated structures. Abbreviations: bc = bursa copulatrix; cd = common duct; pd(b) = paired spermathecal duct (basal); pd(d) = paired spermathecal duct (distal); psd = paired spermathecal duct; sd = single spermathecal duct; ss = single spermatheca; vr - ventral receptacle.

Fig. 21. Mesoconius acca sp. nov., internal characters, Peru. A. Abdomen, ♂. B. Male terminalia. C–D. Phallic bulb and adjacent parts of distiphallus, left (C) and right (D) views. E–F. Spermatheca and associated structures. Abbreviations: bdp = basal distiphallus; ddp = distal distiphallus; e = epandrium; hy = hypandrium.

Fig. 22. A–G. Mesoconius albipedis sp. nov. A. Paratype, ♂, BMNH. B. Male terminalia, including segments 6–8. C. Male terminalia, excluding segments 6–8. D. Spermatheca and associated structures. E. Head and thorax, dorsolateral view. F. Holotype, ♀, BMNH, dorsolateral view. G. Holotype, ♀, lateral view. — H. Mesoconius albimanus Enderlein, 1992, lectotype, ♀, MNBG. Abbreviation: kt = katatergite.

Fig. 20. Mesoconius acca sp. nov., external appearance. A, D–E. Living ♂♂, Wayqecha Biological Station, Peru. B. Head. C. Part of pleuron to show swollen katatergite.

Fig. 24. Mesoconius infestus Enderlein, 1922 (species complex), external characters and colour variation. A. Thorax and base of abdomen, ♂, showing prominent katatergite. B. ♂, DEBU, Baeza, Ecuador. C–D. ♂, DEBU, SierrAzul Lodge, Eucador. E. Head, specimen from SierrAzul. F. Lectotype, ♂, MNBG, Piñipiñi Valley, Peru. G. Holotype of M. enderleini Frey, 1927 (junior synonym of M. infestus), ♀, ZMUH, Colombia. H. ♂, specimen from Colombia. I. ♀, specimen from Colombia. J. Head and thorax, specimen from Bolivia. K. Habitus, ♀, BMNH, oviscape removed, specimen from Bolivia. Abbreviations: e = epandrium; iv = inner vertical bristle; poc = postocellar bristle; ufo = upper fronto-orbital.

Fig. 29. Mesoconius ujhelyianus Enderlein, 1922. A. Holotype, ♂, MNBG. B. ♂ (CMNH). C. ♀ (CMNH). D. Head, ♀. E. Katatergite, ♀.

Fig. 16. Mesoconius rufipleuron sp. nov. A, D. Living ♀♀ in nature. B. Pleuron, to show katatergite. C. Head of paratype. E–F. Spermathecae and associated structures, lateral and dorsal views.

Fig. 18. Mesoconius suzukii sp. nov. A. Typical head. B. Dark head. C. Spermathecae and associated structures. D. Mesopleuron and base of abdomen. E. Abdomen, ♂, ventral view. F. Male terminalia, left lateral view. G. Phallic bulb. Abbreviation: vr = ventral receptacle.

Fig. 15. Mesoconius pasachoa sp. nov. A–B. Holotype prior to capture, ♀, QCAZ. C. Head. D. Spermathecae and associated structures.

Fig. 13. Mesoconius noteques sp. nov., ♀♀. A. Spermathecae and associated structures. B. Head. C. Habitus, lateral view. D. Body, dorsal view.

Fig. 17. Mesoconius rufithorax Enderlein, 1922. A–B. Lectotype, ♀, MNBG, Peru. C. ♀, Bolivia. D. Spermathecae and associated structures, lateral view, Bolivia.

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.

Fig. 7. Mesoconius cosanga sp. nov., holotype, ♀, QCAZ. A. Head and notum. B. Habitus. C. Head and thorax. D. Spermatheca and associated structures.

Fig. 12. Mesoconius nigripleuron sp. nov., internal characters, Peru. A. Male terminalia, lateral view. B. S6 to S8, ♂. C. Abdomen, ♂. D. Spermathecae and associated structures (inset: one of the paired spermathecae with a partially uncoiled stem). E. Male epandrium and cerci, posterodorsal view. Abbreviations: c = cercus; ddp = distal distiphallus; e = epandrium; ejac = ejaculatory apodeme; hy = hypandrium; pa = phallapodeme; pb = phallic bulb.

Fig. 11. Mesoconius nigripleuron sp. nov., living specimens, Peru. A–C. ♀♀. D. ♂.

Fig. 10. Mesoconius hirsutimamma sp. nov. A. Holotype, ♀, IAVH. B–C. Spermathecae and associated structures. Abbreviations: pd(b) = paired spermathecal duct (basal section); pd(d) = paired spermathecal duct (distal section); ps = paired spermatheca; pss = paired spermathecal stem; sd = single spermathecal duct; ss = single spermatheca; vr = ventral receptacle.

Fig. 8. Mesoconius epandribarba sp. nov. A. Holotype, ♂, IAVH. B. Paratype, ♀. C. Abdomen in lateral view, ♂. D. Male terminalia and abdominal segments 5–8. E. Spermathecae and associated structures. F. Male terminalia, left lateral view. G. Phallus, left lateral view. Abbreviations: c = cercus; ddp = distal distiphallus; e = epandrium; ea = ejaculatory apodeme; hy = hypandrium; pb = phallic bulb; pd = paired spermathecal duct; pss = paired spermathecal stem; sd = single spermathecal duct.

Fig. 14. Mesoconius obtusiconus Enderlein, 1922, ♀♀. A. Spermathecae and associated structures, dorsal view, Colombia. B. Oviscape with spermathecae teased out, Colombia. C. Spermathecae and associated structures, lateral view, Colombia. D–E. Holotype, MNBG, Peru. F. Entire specimen, Colombia. G. Head, Colombia. Abbreviations: bc = bursa copulatrix; cd = common duct; ps = paired spermatheca; psd = paired spermathecal duct; pss = paired spermathecal stem; ss = single spermatheca; vr = ventral receptacle.

Fig. 1. Mesoconius albiseta sp. nov., external characters. A. Holotype prior to capture, ♂, QCAZ. B. ♂, showing swollen fore tarsomeres. C–D. Paratype prior to capture, ♀, DEBU. E. Pleuron and base of abdomen to show katatergite. F. Head, ♂.

Fig. 19. Mesoconius suzukii sp. nov. A–C. ♀♀ (B and C are paratypes, IAVH). D. Holotype, ♂, IAVH. Abbreviations: c = cercus; e = epandrium; vle = ventral lobe of epandrium.

Fig. 36. Mesoconius uchumachi sp. nov., holotype, ♂, CBFC. A. Entire specimen. B–C. Abdominal apex. D. Thorax and base of abdomen. E. Head and anterior part of thorax.

Fig. 30. Species of the Mesoconius nono group known only from original type specimens. A–B. Mesoconius hoffmannsi (Enderlein, 1922), holotype (Peru), ♂, MNBG. C–D. Mesoconius ottoi nom. nov. (replacement name for Tanypoda garleppi Enderlein, 1922), lectotype (Bolivia), ♀, MNBG. E. Mesoconius scurrus (Hennig, 1935), holotype (Bolivia), ♂, SMTD.

Fig. 40. Mesoconius oblitus group species known only from original type specimens. A. Mesoconius afurcatus (Hennig, 1935), holotype, ♂, MLUH, Venezuela. B. M. braueri (Hennig, 1935), paratype, ♂, NHMW, Venezuela. C. M. cyclops (Hennig, 1935), holotype, ♂, SMTCk, Bolivia. D. M. filipes Enderlein, 1922, holotype, ♀, MNBG, Peru. E. Aristobata melini Frey, 1927 (junior synonym of M. filipes), syntype, ZMUH, Peru. F. M. rufiventris (Enderlein, 1922), holotype, ♀, MNBG, Colombia. G. M. versicolorus (Enderlein, 1922), holotype, ♀, MNBG, Colombia.

Fig. 33. Mesoconius garyi sp. nov. A–C. Paratypes prior to capture, ♀♀, DEBU. D. Pleuron and base of abdomen. E. Male terminalia. F. Head. G. Spermathecae and associated structures. Abbreviations: bdp = basal distiphallus; e = epandrium; ea = ejaculatory apodeme.

Fig. 31. Mesoconius aurantium sp. nov., holotype, ♀, MUSM. A–B. Habitus. C. Spermathecae and associated structures. D. Pleuron and abdominal base. E. Head. Abbreviations: iv = inner vertical bristle; ov = outer vertical bristle; poc = postocellar bristle.

Fig. 48. Mesoconius rex sp. nov., holotype, ♂, IAVH. A. Habitus, dorsolateral view. B. Head and thorax, dorsolateral view. C. Apex of abdomen, with terminalia detatched (phallus teased out, ejaculatory duct broken). D. Phallic bulb.

Fig. 37. Mesoconius woytkowskii sp. nov., holotype, ♀, CNCI. A–B. Lateral and dorsolateral views. C. Sketch of spermathecae and associated structures, showing separate origins of single and double spermathecal ducts (based on illustration in Albuquerque 1986).

Fig. 43. Mesoconius lobopoda sp. nov. A. Spermathecae and associated structures. B–D. Holotype, ♂, BMNH. E. Abdomen, ♂, left side. F. Abdomen, ♂, ventral view. G. Male terminalia, lateral view, with phallic bulb enlarged in inset. H. Male terminalia, dorsal view. I. Male terminalia, ventral view. Abbreviations: bc = bursa copulatrix; cd = common spermathecal duct; ddp = distal distiphallus; e = epandrium; hy = hypandrium; lo = ʻlobopodʼ pleural lobe of segment 5; pb = phallic bulb; pd = paired spermathecal duct; sd = single spermathecal duct.

Fig. 42. A–C. Mesoconius gelbifacies sp. nov. A–B. Holotype, ♀, QCAZ. C. Spermathecae and associated structures. — D–E. M. keili sp. nov., holotype, ♀, QCAZ, oviscape missing.

Fig. 41. A–B. Mesoconius apa sp. nov., holotype, ♀, CBFC. A. Habitus. B. Head. — C–E. M. apicalis sp. nov., holotype, ♀, QCAZ. C. Spermathecae and associated structures. D. Habitus. E. Head and apex of fore tibia.

Fig. 45. Mesoconius oblitus (Hennig, 1935), external characters. A. Typical ♀, DEBU, Venezuela. B. Colour variant, ♂, USNM, Venezuela. C. Holotype, ♂, SMTD. D. Posterior part of thorax, lateral view. E. Head, ♀, DEBU, specimen from Venezuela. F. Head, ♀, IAVH, specimen from Colombia. G. Colour variant, ♀, IAVH, oviscape removed, specimen from Colombia.

Fig. 49. A–E. Mesoconius ruficrus sp. nov. A. Living ♀. B. Posterior part of thorax, lateral view. C. Head. D. Holotype, ♀, MUSM, dorsal view showing wing. E. Spermathecae and associated structures. — F. Undescribed species of Mesoconius Enderlein, 1922 from Wayqecha Biological Station, Peru.

Fig. 47. Mesoconius quadritheca sp. nov. A, D. Living ♀♀. B–C. Spermatheca and associated structures, dorsal and lateral views.

Fig. 44. Mesoconius nigra sp. nov. A. Head, dorsolateral view. B. Holotype, ♀, CBFC. C. Posterior part of thorax, lateral view. D. Spermathecae and associated structures. E. Living ♀.

Fig. 32. Mesoconius bipleuron sp. nov. A. ♀ with unmarked tibiae. B. Typical ♀. C. Spermathecae and associated structures. D. Head, holotype, ♂, IAVH. E. Pleuron and abdominal base, holotype. F. Holotype, ♂. G–H. Male terminalia. Abbreviations: bdp = basal distiphallus; ddp = distal distiphallus; pb = phallic bulb; vr = ventral receptacle.

Fig. 34. Mesoconius nono sp. nov., ♂♂. A. Holotype, QCAZ. B. Atypical black specimen. C. Another colour form from the type locality. D. Typical form from the type locality. E. Head, holotype. F. Male terminalia and apex of abdomen. G. Male terminalia. H. Phallus, showing broad basal distiphallus with twisted ejaculatory duct terminating in phallic bulb.

Fig. 35. Mesoconius reinai sp. nov., holotype, ♀, IAVH. A. Lateral view. B. Pleuron, showing slightly swollen katatergite. C. Spermathecae and associated structures. D. Head. Abbreviations: cd = common spermathecal duct; iv = inner vertical bristle; pd = paired spermathecal duct; ufo = upper fronto-orbital.