Lasiocnemus

Dikow, Torsten, 2007, Taxonomic revision of the genus Lasiocnemus (Loew, 1851) (Diptera: Asilidae: Leptogastrinae), African Entomology 15 (1), pp. 57-74 : 59-60

Diagnosis

Lasiocnemus is distinguished from other genera of Leptogastrinae by the swollen metathoracic tibiae, closed cell cu p, vein R2+3 angled anteriorly distally, at least two long ventrally-angled setae on ventral surface of metathoracic tibiae, generally brown-and-white coloured wings, and a distribution restricted to the Afrotropical Region.

Redescription

Head. Face pruinose, facial swelling indistinct with only the lower facial margin slightly protruding; mystax consisting of 4–15 macrosetae generally arranged in a single row on lower facial margin; occiput pruinose and covered with erect setae. Antennae, scape short, with setae ventrally; pedicel longer than scape, with setae dorsally and ventrally; postpedicel cylindrical, longer than scape and pedicel combined; stylus with two elements (narrow, cylindrical, long proximal segment and apical ‘seta-like’ sensory element), apical ‘seta-like’ sensory element hyaline or brown; stylus and postpedicel about equal length.

Thorax. Pronotum and postpronotum entirely pruinose; prosternum fused laterally to proepisternum; scutum either entirely covered with pruinosity or predominantly apruinose (pruinosity restricted to anterior, lateral and posterior margins), short or long setae scattered on surface. Macrosetae, one notopleural seta, one supraalar seta, and sometimes one postalar seta; posterior scutum with erect setae; scutellum with long discal scutellar and scutellar setae; katatergite with long erect setae; episterna and epimera covered with dense pruinosity, anepisternum and anepimeron different colour to katepisternum and katepimeron, long more or less erect setae on anepisternum, katepisternum, and katepimeron; postmetacoxal area sclerotized with suture medially. Legs, generally dark brown to black; coxa pruinose; prothoracic and mesothoracic femora with erect setae dorsally and anteriorly, metathoracic femora with erect setae on all surfaces, metathoracic femora expanded, clubbed; tibiae generally coloured evenly and with erect setae, sometimes with dorsal pale yellow stripe and short setae only; mesothoracic tibiae with three long setae on posteroventral surface distally, metathoracic tibiae generally with erect setae on all surfaces sometimes only proximally, expanded and broadest medially, metathoracic tibiae with at least two long ventrad-angled setae on ventral surface; first tarsomere about same length as second and third combined, tarsomeres with stout black setae ventrally except for fourth and fifth; claw black, long, pointed; empodium from about half length of claw to nearly length of a claw. Wings ( Figs 11–16 ), length = 4.5–15.0 mm; microtrichia generally on anterior and posterior margin and distally, entirely hyaline or opaque with pattern of brown and white-coloured spots/stripes, veins brown; pterostigma distinct brown; cell cu p closed and stalked, all other marginal cells open, cell d terminating in M2 and M3 with M1 situated proximally at about half length of cell d, R2+3 distally angled anteriorly; haltere light brown to brown.

Abdomen. T entirely brown and grey pruinose, T 2 in proximal half with erect setae laterally, remaining T with short setae; S pruinose and setose, S2 pruinose or apruinose in proximal half.

Male terminalia ( Figs 5–10 ): surstylus with rounded distal tip, ventral lobe well-developed, surstylus setose; hypandrium triangular-shaped (ventral view), lateral margin expanded to form protruding carinae distally; gonocoxite fused to hypandrium with visible suture, gonocoxite fused to proximal epandrium, gonostyli and lateral processes of gonostyli of equal size, situated distally on gonocoxite. Aedeagus. Only seen in dorsal view as a block between the aedeagal apodeme and dorsal aedeagal sheath; dorsal aedeagal sheath comprising single pointed tube; ventral aedeagal sheath plate-like, triangular; lateral apodeme cylindrical; aedeagal apodeme rounded, varying diameter.

Female terminalia ( Figs 17–22 ): unspecialized ovipositor; S8 invaginated medio-distally with short macrosetae; furca (S9) U-shaped, sclerotized throughout; bursa copulatrix cylindrical, expanded and angled 180° medially; three spermathecae present with median spermatheca larger than lateral ones, spermathecal ducts tubular with a distinct smoothly angled banana-shaped part medially; spermathecal reservoirs sac-shaped, longer than wide, broadest proximally.

Distribution. Species of Lasiocnemus are restricted to the Afrotropical Region ranging from the Ivory Coast in the northwest to Somalia in the east and South Africa in the south. Every species except La. hyalipennis occurs in at least one biodiversity hotspot ( Figs 23–24 ; Myers et al. 2000, Conservation International 2005), but none are endemic to any particular hotspot (see Type locality, distribution, and Biodiversity hotspot under each species).

Etymology. Lasios (Greek) = hairy, woolly; cnemo- (derived from Greek kneme) = leg, shin. Refers to the setose metathoracic tibiae that represent an autapomorphy for Lasiocnemus .

Figures

Fig. 23. Map of sub-Saharan Africa with biodiversity hotspots, shaded in grey, showing distribution of Lasiocnemus griseicinctipes (■), La. hermanni (▲), La. lugens (●) and La. obscuripennis (★). Type localities with open symbols.

Fig. 24. Map of sub-Saharan Africa with biodiversity hotspots, shaded in grey, showing distribution of Lasiocnemus fascipennis (●), La. hyalipennis (■), La. londti (▲), and the unidentified female specimen deposited in the SAMC (★). Type localities with open symbols.

Figs 11 – 16. Wings of species of Lasiocnemus. 11, La. fascipennis; 12, La. griseicinctipes; 13, La. hermanni; 14, La. hyalipennis; 15, La. londti; 16, La. lugens. Scale bars = 4.0 mm.

Figs 5 – 7. Male terminalia of Lasiocnemus londti. 5, Lateral view; 6, dorsal view; 7, ventral view. Scale bar = 1.0 mm.

Figs 8 – 10. Male terminalia and aedeagus of Lasiocnemus lugens. 8, Terminalia lateral view; 9, aedeagus dorsal view; 10, aedeagus lateral. Scale bar = 1.0 mm.

Figs 17 – 22. Female spermathecae of species of Lasiocnemus in lateral view. 17, La. fascipennis; 18, La. griseicinctipes; 19, La. hermanni; 20, La. hyalipennis; 21, La. londti; 22, La. lugens. Note: second lateral spermathecal duct and reservoir, in lateral view situated ventral to median reservoir, omitted. Scale bars = 1.0 mm.