Anasillomos juergeni Dikow, 2015
- GBIF Backbone Taxonomy
- Published in
- Dikow, Torsten. 2015. Review of Anasillomos Londt, 1983 with the description of a new species (Insecta: Diptera: Asilidae). Biodiversity Data Journal 3: e4652.
- Anasillomos juergeni
Head: wider than high, black; vertex slightly depressed (less than 60° angle on median margin of compound eye); facial swelling extending over lower ¾ of face, white pubescent; mystax white macrosetose, extending over lower ¾ of face; ommatidia of different size, at least some median ommatidia distinctly larger; postgena posterior margin simple, smooth; frons (at level of antennal insertion) more or less parallel-sided, apubescent antero-medially, grey to golden pubescent otherwise, white setose and macrosetose laterally; ocellar tubercle golden pubescent, white setose and macrosetose; vertex golden pubescent, asetose; median occipital sclerite (m ocp scl) with several white macrosetae; postocular (pocl) setae straight, white macrosetose; occiput predominantly grey pubescent, dorso-medially with V-shaped apubescent stripes and medially with longitudinal light brown pubescent stripe, white setose.
Proboscis and maxillary palpus: proboscis straight, black; postmentum plate-like, straight, ventral margin entirely smooth, white setose ventrally; prementum circular in cross section proximally, with dorso-median flange, white setose proximo-ventrally; labella reduced, fused to prementum entirely, small, only forming distal tip of proboscis, apex rounded; maxillary palpus two-segmented, black, distal palpomere cylindrical, yellowish setose, distally white macrosetose; stipites fused entirely medially, apubescent, long white setose.
Antenna: light brown, lightly grey pubescent; scape 2x as long as pedicel, short white setose dorsally and long white macrosetose ventrally; pedicel white setose distally; postpedicel cylindrical (same diameter throughout), almost 2x as long as scape and pedicel combined, sparsely white setose dorso-distally; stylus comprised of 1 element, asetose; apical seta-like sensory element situated apically on stylus.
Thorax: dark brown to black, postpronotal lobes light brown to orange; prosternum apubescent, separated from proepisternum, square to rectangular in shape (straight dorsally); proepisternum grey pubescent, white setose and macrosetose; cervical sclerite long white setose; antepronotum golden pubescent, white setose and macrosetae; postpronotum golden pubescent, medially white setose, laterally long yellowish macrosetose, postpronotal lobe white setose and long yellowish macrosetose; pleuron predominantly grey and golden pubescent, katepimeron and antero-dorsal meron + metanepisternum apubescent; proepimeron white setose; anepisternum anterior half asetose, posterior half long white setose, supero-posteriorly white setose (not macrosetose); anterior basalare asetose, posterior basalare asetose; anepimeron predominantly asetose, antero-dorsally white setose, katepisternum predominantly asetose, postero-dorsally white setose, katepimeron asetose, katatergite white setose and long yellowish macrosetose; meron + metanepisternum asetose, metakatepisternum asetose, metepimeron sparsely white setose; anatergite long white setose; scutum predominantly grey pubescent, narrow paramedian stripes (just reaching past transverse suture) and sub–lateral spots (1 anterior and 2 posterior to transverse suture) brown pubescent; scutum setation: short white setose anterior and long white setose posterior to transverse suture, setae with small sockets, 3 npl setae, 3–4 spa setae, 4 pal setae, 1 white presutural dc macroseta and 3 white postsutural dc macrosetae, acr setae white, presuturally short and longer postsuturally, median posterior scutum (between dc setae) long white setose, setae directed posteriorly; scutellum grey pubescent, ds sctl setae present, long white setae in posterior half, ap sctl setae present, 5–6 long white macrosetae; postmetacoxal area entirely membranous.
Leg: light brown to brown, apubescent, all setae circular in cross section; pro coxa dark brown, grey pubescent, white setose and macrosetose; pro femur brown, dorsally dark brown, short white setose, white macrosetose: 1 antero-median, 5–6 postero-dorsal, and 6–7 ventral macrosetae; pro tibia brown, short white setose, white macrosetose: 5 in 1 antero-dorsal row, 5 in 1 postero-dorsal row, 4 long in 1 postero-ventral row, distally with 6–7 long white macrosetae; mes coxa dark brown, grey pubescent, white setose and macrosetose; mes femur brown, dorsally dark brown, short white setose, white macrosetose: 2 antero-median, 6–7 postero-dorsal, and 5–6 ventral macrosetae; mes tibia brown, short white setose, white macrosetose: 3 in 1 antero-dorsal row, 2 in 1 antero-ventral row, 4 in 1 dorsal row, 3 in 1 postero-ventral row; met coxa brown, grey pubescent, white setose and macrosetose, anteriorly without any protuberance; met trochanter white setose and macrosetose, cylindrical, medially without protuberance; met femur brown, dorsally dark brown, short white setose, white macrosetose: 6 anterior, 6–7 ventral, and 4–5 postero-ventral macrosetae; met tibia brown, straight, short white setose, white macrosetose: 4 in 1 antero-dorsal row, 3 in 1 dorsal row, 4–5 in 1 ventral row; proximal pro, mes, and met tarsomeres as long as following 2 tarsomeres combined, pro, mes, and met tarsomeres white setose dorsally, pro tarsomeres white macrosetose disto-laterally and disto-ventrally, mes and met tarsomeres white macrosetose laterally and ventrally; pulvilli well-developed (as long as claw); claw abruptly angled distally, pointed; empodium setiform, well-developed (as long as pulvilli).
Wing (Fig. 5d): length 8.0–9.5 mm, wing membrane hyaline, narrowly colored light brown along distal veins, without microtrichia; C circumambient (developed around entire wing), anterior wing margin straight; R₂₊₃ distally distinctly arching anteriorly, r₁ open; R₄ terminating anterior to wing apex, distinctly arching anteriorly, stump vein (R₃) absent; r₄ open, R₄ and R₅ diverging from each other; R₅ not reaching C (or wing margin); r₅ closed and petiolate; M₁ not reaching C (or wing margin); cell d closed by base of M₂ and m-m, M₂ and m-m not aligned, r-m situated in distal half of cell d; m₃ open, M₃ and M₄ approximating at C; cua closed at C (non-petiolate); alula well-developed; microtrichia on posterior wing margin arranged in a single plane.
Abdomen: brown to black, laterally light brown to orange, tergites smooth, setae with small sockets only; T1 white setose, laterally long white macrosetose, grey pubescent, entirely sclerotized medially, dorsal surface smooth, without protuberances; T2–8 entirely sclerotized, predominantly black, sometimes brown to orange laterally, lightly grey pubescent, medially with distinct longitudinal dark grey pubescent stripe, white setose, setae longest on T2, medial setae directed laterally; marginal macrosetae absent from T2–8, medial macrosetae absent from T2–8; S1–8 black, lightly grey pubescent, white, erect setose.
Female (Fig. 9a, b, c): T7 and S7 without modifications, ovipositor comprised of 8th and following segments, T6–8 apubescent, setation directed anteriorly on T6–7 and erect on T8; T8 anteriorly with internal rectangular apodeme (entirely fused to T), S8 plate-like, hypogynial valves extending; T9 and T10 entirely fused, sclerites not distinguishable, T10 divided into two heavily sclerotized acanthophorite plates, with 7, white acanthophorite spurs per plate; 3 spermathecae, all equally large, reaching anterior end of segment 6; common spermathecal duct short, not extending beyond tip of furca, individual spermathecal ducts long; ejection apparatus absent; spermathecal reservoirs formed by more or less expanded and coiled ducts, weakly sclerotized; furca (S9) formed by single, inverted V-shaped sclerite, median sclerite (at posterior tip) absent, anterior furcal apodeme absent.
Male (Fig. 8a, b, c): T1–T8 and S1–S8 entire (without modifications); hypopygium dark brown, rotated by 180°, directed posteriorly; epandrium divided medially into two halves, joined proximally; hypandrium well-developed, triangular, distally with short postero-median projection, distinctly separated from epandrium by gonocoxite, not fused to gonocoxite; gonocoxite partially fused to epandrium proximally, gonocoxal apodeme present, short, at most slightly extending hypopygium proximally; gonostylus present, positioned distally on gonocoxite; subepandrial sclerite asetose, ventrally smooth (without protuberances), laterally straight (without protuberances), distally simple, straight margin; cerci separate (not fused medially); 1 aedeagal prong, tip pointed, with dorsal bipartite protuberance, dorsal aedeagal sheath short, sperm sac entirely free; lateral ejaculatory process present, large triangular sclerite, free (not surrounded by ventral aedeagal sheath); ejaculatory apodeme formed by single vertical plate (two lateral surfaces).
The species is distinguished from its congener by the dorso-posterior white setose anepisternum (not macrosetose, Figs 5b, 6b, 7b), the distinct median longitudinal dark grey pubescent stripe on the abdominal tergites (Figs 5a, 6a), the absence of a pubescence pattern on the lateral abdominal tergites (Figs 5b, 7b), the presence of a dorsal bipartite protuberance on the aedeagus tip (Fig. 8c), and the presence of only short macrosetae on the tip of the pointed hypandrium (Fig. 8b).
All recently collected specimens during field work at or near the Gobabeb Research and Training Center conducted in February 2012 were perching on sand. The majority of specimens were collected on the large sand dunes south of the station and Kuiseb river bed (Fig. 10a, b) while a few were encountered on the small dunes west of the Kuiseb river bed (Fig. 10c). The flies are very fast fliers and fly away even when one is several meters away. An attempt was made to photograph them in the field, but I was unable to get sufficiently close (see Fig. 10a with a fly in the center).
Four female specimens have been captured with prey at or near Gobabeb of which three were feeding on Bombyliidae (Diptera) and one on Ichneumonidae (Hymenoptera).
The species is named after and dedicated to the memory of my late father, Jürgen Dikow, who has always been supportive of my entomological work and was excited to hear about every new species discovery I made.
The species is so far only known from Namibia and in particular from the eastern edge of the Namib desert sand dunes (Gobabeb, Homeb, and Sesriem) as well as the Karoo in southern Namibia (near Grünau) (Fig. 11).
Namibia: Erongo: Namib-Skeleton Coast National Park, Gobabeb (dunes south of station at 23°34’17’‘S 015°02’52’'E).
Not known to occur in any of the southern African biodiversity hotspots (Cape Floristic Region, Maputaland-Pondoland-Albany, or Succulent Karoo).
- Anasillomos juergeni Dikow, 2015