Anaclastoctedon, Plant, 2010

Plant, Adrian R., 2010, Anaclastoctedon (Diptera: Empididae: Hemerodromiinae), A New Genus From Asia And Australia, Raffles Bulletin of Zoology 58 (1), pp. 15-25 : 16-19

Anaclastoctedon new genus

Type species, Anaclastoctedon lek , new species ( Figs. 1–12 )

Diagnosis. – A characteristic genus of the Empididae subfamily Hemerodromiinae with raptorial forelegs widely separated from the mid legs and fore femur bearing distinct regular rows of setae ventrally. Anaclastoctedon is distinguished from other Hemerodromiinae by the combination of (1) all long veins (R 2+3, R 4+5, M & CuA 1) linear, unbranched; (2) cell br longer than bm; (3) male genitalia strongly reflexed anteriorly over abdomen; (4) epandrium separate from hypandrium; (5) male cercus free, greatly enlarged, anteriorly or vertically projected, spade-like apically, usually with smaller pointed internal process basally; (6) postpedicel of antenna short, almost globular with apical stylus at least 4× as long and lacking basal article.

Description. – Head subspherical ( Figs. 7, 8 ), somewhat dorsoventrally flattened with eyes widely separated on frons; narrowly separated on face in both sexes, widening towards mouth; anterior ommatidia slightly enlarged in both sexes. A pair of ocellar setae (usually with a few smaller setulae around ocellar protuberance) and pair of much smaller but distinct frontal setae mid way between prominent ocellar protuberance and base of antennae. One pair of distinct vertical setae situated close to eye margin. Postocular setae stout and erect, uniserial, situated some distance behind eye margin; uppermost postocular seta sometimes placed on slight lateral prominence of vertex between and at same level of verticals; series usually becoming weaker and sometimes 2–3 serial ventrally where sometimes merging into patch of finer setae on lower occiput and behind mouth.

Mouthparts small; proboscis slightly anteriorly directed, no longer than head is deep, apically pointed. Labellum broadly ovate bearing fine setulae posteriorly. Palpus very small, longer than wide with fine but long setulae apically.

Antenna with basal segments as long as wide; scape with distinct dorsal seta; pedicel with circlet of setae apically. Postpedicel at most 1.5× long as wide ( Fig. 3 ), almost globular but pointed apically, sometimes appearing rather narrower in lateral view. Stylus much longer than postpedicel (usually at least 4× as long), not obviously swollen basally and rather thread-like, almost bare apart from sparse microscopic pile; basal articles apparently absent.

Thorax. Moderately arched ventrally in profile ( Figs. 7, 8 ). Postpronotum strongly developed, protuberant. Scutum with prescutellar depression broad; supraalar area sometimes outwardly produced with outer margin rather triangular in dorsal view. Usually two pairs of dorsocentral setae strongly developed, anterior pair in line with postpronota, other slightly anterior of position of notopleurals; often one or two pairs of minute dorsocentrals posteriorly. Supraalar very strong, postpronotal and upper notopleural present and usually strong. Lower notopleural weak or absent and usually one or more small setae between notopleural and postpronotal areas weaker still. A pair of scutellar setae present. Laterotergite bearing several setae.

Legs with front coxa almost as long as thorax ( Fig. 7 ); linear series of setae anteriorly, weak, becoming longer distally and with a few distinct setae at tip. Mid and hind coxae much shorter bearing a few setae laterally and apically in front. Front femur as long as front coxa, strongly inflated, much stouter than other femora, widest at middle; ventrally with double row of strong setae on distal 0.7 between which is double row of short peg-like denticles; dorsal and posterior faces with fine setae, anterior face almost bare. Front tibia slightly curved, geniculate at extreme base; ventrally with single row of minute adpressed denticles which articulate against corresponding double row of denticles on front femur when limb is reflexed; an apicoventral ‘fan’ of minute setulae; otherwise with only short fine setulae and scattered perpendicular cilia (minute erect specialised setae of probable sensory function). Mid and hind femora and tibiae rather short bearing mostly short setae, longest dorsoapically on posterior femur and tibia and on mid tibia. Tarsomeres bearing short setulae; longest and strongest anteroventrally on distal segments of mid and hind legs but sometimes longish on front metatarsus. Front tarsomere 1 hardly longer than tarsomere 2, the segments becoming progressively and gradually shorter distally with tarsomere 5 slightly flattened and enlarged; mid and hind tarsal segments similar but tarsomere 1 longer than tarsomeres 1 and 2 combined.

Male abdomen with tergites 2–6 broad, tergites 7 and 8 reduced. All segments with scattered fine setae and longer setae on tergite 5. Genitalia ( Figs 1, 2, 4 , 9–12 ) strongly reflexed forward ( Fig. 7 ). Hypandrium greatly enlarged, broader than preceding segments of abdomen, with keel-like posterior margin, hypandrial lamellae partially separated posteriorly by narrow micropilose membrane; epandrium smaller, lamellae not fused posteriorly or with hypandrium. Cerci free, greatly enlarged, anteriorly or vertically projected, spade-like apically ( Figs. 1, 2, 4 , 9–11 ); usually with smaller pointed internal process basally (much reduced in A. sano new species). Phallus slender, strongly anteriorly directed; parameral sheath rather broad, often with complex hooked structures apically ( Figs. 4 , 9–12 ).

Female abdomen with setae sparser and weaker. Cerci moderately long, dorsoventrally flattened ( Fig. 8 ), appearing narrower in lateral view; bearing some short setae and some longer ones apically. Spermatheca spherical.

Wing ( Figs. 5, 6 ) narrow basally with axillary angle hardly developed. Vein C circumambient but weak beyond tip of R 4+5. Vein Sc fading apically; R 1 rather short, joining C just beyond end of basal cells. Radio-cubital praefurca short, linear, not fading basally at junction with R 1. Cell br longer than cell bm; cell bm quadrate apically with crossvein bmcu usually perpendicular (rarely somewhat acute); cell cup quadrate apically, slightly shorter than bm. Vein A 1 +CuA 2 short, continuing beyond posteroapical margin of cell cup but terminating well before wing margin. Crossvein dm-cu absent (cell dm absent). Long veins (R 2+3, R 4+5 & CuA 1) linear, reaching wing margin; vein M usually linear, but occasionally vestige of M 2 present at wing margin but completely absent basally ( Fig. 6 ). Marginal cilia short along costa, longer on posterior margin. Stigma absent. Basal costal seta present.

Etymology. – The name derives from anaclastos (Greek) meaning reflexed and ctedon (Greek) meaning comb; ‘reflexed comb’ in reference to the form of the front leg.

Figures

Figs. 1–4. Anaclastoctedon new genus: 1. A. antarai new species, male terminalia. 2–4: A. lek new species. 2. apex of male cercus, internal face; 3. postpedicel and stylus of male; 4. male terminalia. Abbreviations: cer, major lobe of cercus; cip, internal process of cercus; epan, epandrium; hypan, hypandrium; ph, phallus and parameral sheath; sur, surstylus.

Figs. 5–8. Anaclastoctedon new genus: 5. A. lek, new species, wing of male; 6. A. antarai new species, wing of female; 7. A. lek, new species, male habitus; 8. A. antarai female habitus. Abbreviation: M2, apical section of vein M2.

Figs. 9–12. Anaclastoctedon new genus: 9. A. ancistrodes new species, male terminalia; 10. A. sano new species, male terminalia; 11–12. A. prionton new species; 11. male terminalia; 12. apex of parameral sheath, dorsal aspect.