Anaclastoctedon lek, 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 : 19-20

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Anaclastoctedon lek

new species

Anaclastoctedon lek   , new species

( Figs. 2–5, 7 View Figs View Figs )

Material examined. – Holotype. Male, THAILAND: Chiang Mai, Doi Inthanon National Park, Kew Maepan Trail , 18°33.162'N, 98°28.810'E, 2,200 m, Malaise trap, 9–16 Feb.2007, coll. Y. Areeluck ( T1795 , QSBG). GoogleMaps  

Paratypes. – Same data as holotype, 8 males, 20 females ( QSBG, NMWC); 1 male, 22–29 Dec.2006 ( QSBG, T1888 ); 1 female, 5–12 Jan.2007 ( QSBG, T1928 ); 6 males, 12–19 Jan.2007 ( QSBG, T1931 ); 2 males, 4 females, 23 Feb. –2 Mar.2007 ( NMWC, T1771 ); 4 males, 5 females, 2–9 Mar.2007 ( NMWC, T1777 ); 11 males, 10 females, 16–23 Mar.2007 ( NMWC, IRSNB, MNHN, ZRC, T1929 ); 1 male, 2 females, 16–23 Mar.2007 ( NMWC, T1813 ); 1 male, 2 females, 23 Mar. – 1 Apr.2007 ( QSBG, T1819 ); 2 females, 1–8 May.2007 ( QSBG, T1824 ) GoogleMaps   : Checkpoint 2, 18°31.554'N, 98°29.940'E, 1,700m, 1 male, 22–29 Dec.2006 ( QSBG, T1891 ); 1 male, 29 Dec.2006 – 5 Jan.2007 ( QSBG, T1897 ); 2 females, 5–12 Jan.2007 ( QSBG, T1913 ); 1 male, 7 females, 2–9 Feb.2007 ( QSBG, T1793 ); 2 females, 16–23 Feb.2007 ( QSBG, T1805 ); 1 female, 23 Feb. –2 Mar.2007 ( QSBG, T1775 ) GoogleMaps   . Loei, Phu Kradueng National Park , 16°53.092'N, 101°47.413'E, savannah in pine forest, 1,257 m, coll. T. Srisa-ad, 16 females, 9–16 Jan.2007 ( NMWC, IRSNB, MNHN, ZRC, T1226 ); 14 females, 16–23 Jan.2007 ( QSBG, T1229 ) GoogleMaps   ; savannah near waterfall, 16°53.443'N, 101°46.946'E, 1,247 m, coll. S. Gongla-sae, 1 male, 4 females, 28 Dec.2006 – 3 Jan.2007 ( NMWC, T1221 ) GoogleMaps   .

Diagnosis. – A small species with thorax entirely black. The head is distinctly dorsoventrally flattened with dense pale pile ventrally. The antenna almost entirely yellow in male but postpedicel black in female.

Description. – Male. Length 1.6–1.9 mm. Head distinctly dorsoventrally compressed ( Fig. 7 View Figs ); black, face paler, all setae whitish yellow; pile behind mouth and on lower occiput long and dense. Mouthparts small, pale; proboscis much shorter than head is deep, apically darkened. Antenna yellow with only apical 0.3 of stylus darkened. Stylus 4× as long as postpedicel ( Fig. 3 View Figs ).

Thorax blackish brown, setae yellow; postpronotal setae almost as long as anterior dorsocentral, posterior dorsocentral smaller; upper notopleural and supraalar very large.

Legs yellow with apical tarsomeres blackish. All setae yellow excepting double row of black denticles ventrally on F 1 and single row of black denticles beneath T 1. F 1 with 4–5 av and 5–6 pv setae, all stout, basal seta of av series sometimes slightly displaced ventrally towards median line and positioned immediately basal of double row of 11–14 av and 9–11 pv denticles.

Abdomen blackish brown; all setae yellowish, longest dorsally on pregenital tergites. Genitalia ( Fig. 4 View Figs ) blackish with phallus and parameral sheath yellow. Major lobe of cercus ( Figs. 2, 4 View Figs ) petiolate basally, much broader apically, with stout spine-like setae and finer bristles apically; smaller basal lobe apically narrow with small apical spine. Phallus strongly curved apically.

Wing ( Fig. 5 View Figs ) membrane clear, veins yellowish.

Female. – Length 1.8–2.3 mm. Similar to male but postpedicel and stylus entirely blackish. F 1 with 4–5 av and 5–6 pv setae between which are 11–17 av and 10–12 pv denticles. Abdomen blackish brown, becoming rather paler and with longer setae apically.

Etymology. – The specific epithet lek (Thai)   means small and refers to the small size of this species.

Remarks. – Known only from northern Thailand on the upper slopes of Doi Inthanon, Chiang Mai Province above 1,700 m and from about 1,200 m on the mesa sandstone mountain Phu Kradueng in Loei Province. The Doi Inthanon sites were hill evergreen and moist hill evergreen forests while at Phu Kradueng, the habitat was ‘thung’ (savannah grassland) mixed with Pinus   . Capture dates range from late December to early May with peak adult activity in February and March coincident with cool dry becoming hot dry general climatic conditions although the high elevation and forest cover of the capture sites probably ensures moist rather cool conditions throughout the year. An apical remnant of vein M 2 is sometimes present at the wing margin, especially in examples from Loei. The cercus of the single male from Loei is of slightly different colour and shape to specimens from Chiang Mai but the differences are considered too small to warrant specific separation of the Chiang Mai and Loei populations.


National Museum of Wales


Institut Royal des Sciences Naturelles de Belgique


Museum National d'Histoire Naturelle


Zoological Reference Collection, National University of Singapore


Tavera, Department of Geology and Geophysics