Dasybasis rieki, Ferguson, David J. & Yeates, David K., 2015

Ferguson, David J. & Yeates, David K., 2015, A new species, new immature stages, and new synonymy in Australian Dasybasis flies (Diptera: Tabanidae: Diachlorini), Zootaxa 3946 (2), pp. 261-273 : 263-267

Dasybasis rieki sp. nov. Ferguson & Yeates

( Figs 1 , 2 , 3 , 4 , 5 , 6, 7, 8 )

Diagnosis. Female: Occipital hairs black admixed with golden. Frons parallel sided. Callus rectangular, appearing square, glossy, touching eye margin, medial extension slightly longer than the laterodorsal extensions. Postocular rim narrow to broad. Subcallus flat to swollen, usually pilose. Sternites with dense grey pubescent surface that obscures integument colour; medially with a broad longitudinal strip of semi-erect black hairs, sternite lateral margins covered with semi-erect white hairs.

Holotype: Female. Australia, New South Wales. South Durras Beach; sifted from sand along upper beach, 30 August 2013. Emerged: 17 September 2013. D.J. Ferguson & D.K. Yeates, (ANIC_29: 030321) ANIC.

Paratypes: 4 females, 4 males. Australia, New South Wales: 1♀, same data as Holotype (ANIC_29: 030322); 1♂, 10 miles North of Batemans Bay, 14 October 1959, Z. Liepa (ANIC_29:029850) ANIC: Victoria: 1♀, 1♂, Mallacoota, Betka Beach; 37°25’59”S 149°44’28”E; 29–30 November 2012. D.J. & R.L. Ferguson (ANIC_29: 030323 –24) ANIC; 1♀, Mallacoota, Betka Beach; 5–6 September 2013; emg: 1 October 2013; 37°25’59”S 149°44’28”E; D.J. & R.L. Ferguson, (ANIC_29:029848) ANIC; 1♂, Anglesea, 6. November 1958, N. Dobrotworsky, (ANIC_29:029849) ANIC; Tasmania: 1♂, Beach Zone, Rupert Point, Pieman River, 1 January 1954, T.G. Campbell, (ANIC_29:029847); 1♀ Eagle Hawk Neck, 20 January 1949, E.F. Riek, (ANIC_29: 030325) ANIC.

Description. Female: Body Length: 14 mm (female paratype series: 12–14.5 mm; male paratype series: 14–16 mm); ( Figs. 1–5 ). Head. Width: 6 mm (female paratype series: 5.8–6.1 mm; male paratype series: 5.8–6.2 mm); eyes blackish grey, densely covered with white hairs, hairs absent along dorsal and dorsolateral margins, (male paratype series: with broad near elliptical band of large eye facets, horizontal line level with base of frons, margined by smaller eye facets; yellowish hairs): Postocular rim (por, Fig.5 A) Marginally broad with black hairs admixed with golden. Ocellar triangle reduced, only a remnant of the median ocellus present. Frons (fr, Fig.5 ), index: 3.5, parallel/ slightly divergent, pale grey, with short, black hairs admixed with golden hairs. Frontal callus rectangular, appearing squarish, touching eye margin, glossy, pale hairs on lateral areas, bare medially, medial extension slightly longer than the laterodorsal extensions. Subcallus slightly swollen, covered in pale grey pubescence, dorsal margin with a pair of short triangular glossy areas, lateral and dorsolateral to antenna with short white hairs. Parafacial covered with pale grey pubescence and silver-white hairs, face pale grey with silver-white hairs admixed with black hairs; beard hairs longer, silver-white. Palp extends to the middle of the proboscis, tapering to a point, and covered with short white hairs admixed with black towards the apex (male paratype series: elongate, conical, with long white hairs, admixed with several stronger short black hairs on apical half), basal segment short and bulbous. Proboscis black, fleshy and the same length as head height; labellum large, with thin sclerotised dorsal margin at theca. Antennal scape (scp, Fig.5 A) and pedicel (pd, Fig.5 A) grey with short, black setae dorsally, lateral setae short, erect and white, ventral setae black admixed with white, long and erect; pedicel with dorsal tooth; flagellum (fgm, Fig. 5 ), first 4 basal flagellomere fused (fg1–4, Fig. 5 ) blackish, basally with grey velvet pubescence, dorsal margin with broad obtuse angle, small black setae on the apex, anterior edge slightly concave, with 2 pseudo-segments evident; fg5 –fg8 black, slightly tapering, with fg8 conical, several small black setae on apex; length of fg5–fg8 approximating the length of fg1–4. Thorax. Scutum dark grey with grey medial vittae on anterior half, dorsocentral vittae pale grey, with lateral areas broadly pale grey; white hairs admixed with golden along vittae, with black hairs between vittae; scutellum dorsally dark grey with long black hairs, posterolateral margins grey, with long white hairs. Notopleural lobe grey; anepisternum with admixed white and black pile; pleura and coxae grey with long silver-white hairs. Legs. All femora blackish grey surfaced with dark grey pubescence. Fore-tibia basally yellowish grey, surfaced with grey pubescence; mid and hind tibia dark grey (male paratype series: tibia can be yellowish darkening apically); hind-tibial fringe black when viewed dorsally, admixed black and white when viewed ventrally. Wing. Wing length: 12.5 mm (female paratype series: 12–13 mm; male paratype series: 11–12.5 mm), hyaline, veins dark brown-grey, vein sc setulose dorsally and ventrally, appendix of vein R 4,1.5x the distance the appendix is from R 5 (female paratype series: 6 specimens with the same or are shorter than the distance the appendix is from R 5; Male paratype series: 5 specimens with the same or are shorter than the distance the appendix is from R 5). Haltere. Pedicel dark grey, knob ventrally and dorsally dark grey. Abdomen. Dorsal surface grey, densely covering of black, semi-erect hairs; tergites 1–7 distal margin pale grey with white hairs; medial hairs short, pale grey triangles, with white hairs along apical margin, (male paratype series: apical bands brownish to blackish brown with some yellow-brown mottling, apical margin yellow-brown). Sternites densely covered with grey pubescence, a broad longitudinal strip of semi-erect black hairs medially, broad lateral margins covered with semi-erect white hairs.

Terminalia. Paratype female: (ANIC_29:029848) ( Fig. 8 ). Dorsal view; cerci darkly sclerotised, subtriangulate; tergite 10 ovoid, medially divided; tergite 9 darkly sclerotised, distinctively narrow, widely divided. Three spermathecal ducts extend from darkly sclerotised genital fork, length approximately 10x the maximum length of the cercus, basal third of ducts transparent, becoming opaque then dark along the slightly swollen spermathecal bulb that tapers towards the apex (refer: Fig. 8 ).

Paratype male: (ANIC_29: 030324). ( Figs. 6, 7 ). 6. Dorsal view; cerci darkly sclerotised and subtriangulate; tergite 9 posteriorly undivided, apically elongated and tapered ( Fig. 6 ). Gonocoxae, gonostyli and aedeagus ( Fig. 7 ).

Etymology. The specific epithet ‘ rieki ’ is to honor Dr Edger F. Riek, for his contribution to entomology, who was the first to collect this species in 1949.

Larva. Length: 22–24.5 mm long and 3.5–4.5 mm wide ( Fig. 9 A). Thoracic segments 1–3, tapering anteriorly; abdominal segments I–IV of sub-equal diameter; segment V–VII slightly tapered; segment VIII short, half the length of segment 7; all segments with fine longitudinal surface striations; colour creamy white (note: D. macrophthalma (Schiner) , also breeds on beach species and is described as creamy white; see: English, 1949); length. Head capsule ( Fig. 9 C, D) retractable, 5.5 mm long from the tip of the labrum to the posterior bilobed extremity of the epicranium; greatest width 1 mm; anterior darkly sclerotised; cranium weakly sclerotised; labrum laterally compressed with patches of short spines on lower lateral surfaces; distal mandibular hook heavily sclerotized, black, curved with serrated lower edge; mandibular brush bristles pale; anterior margin of the maxilla narrowly flanged; maxillary lacinia broad at the base, terminating in a short, posteriorly directed apex, inner surface with short pale spines; maxillary palp short with 2 segments; antenna arises from the anterolateral subapical surface of a forward projecting process; 1st segment tapered to a narrow aperture, holding two very small and thin microsetae that appear connected at their base; labium ( Fig. 9 B) anterolateral edges curved laterally with deep cleft medially; tentorial rods dorsally troughed medially, divided subapically. Thorax. ( Fig. 9 A) Prothorax annulus of pale brown granular membrane, with 5 posteriorly directed areas of pale brown granular membrane, these tapered areas extend to the anterior margin 2nd segment, each without a line of minute pores along mid-line, the ventral extension narrower that the widely spaced lateral extensions; segment 2 and 3 anterior margins thinly edged with granular membrane. Abdomen ( Fig. 9 a), segments I–V anterior edge with raised creeping welts, creamy white granular membrane along posterior edges tapering laterally. Segments I–VII with 3 pairs of ventral and lateral prolegs on each side; segments V–VII with lateral-line of pores on posterior half of segment; segment VIII posterior spiracle ( Fig. 9 E) with the sclerotised surface textured all over with small raised spots; an evenly curved elliptical margin with many filaments around the margin, with a distinct gap on each side (see Fig. 9 E); apices with numerous, short pale bristles, (it is worth comparing with the posterior spiracle of D. macrophthalma , which has a completely textured, sclerotised surface, evenly curved elliptical margin and 30 evenly distributed filaments around margin; see: Fig. 8 ; in English, 1949).

Pupa. Length: 18 mm ( Fig. 10 A). Head: The cephalothoracic setae raised from a truncated basal tubercle ( Fig. 10 B); setae long; apical quarter laterally compressed; apex rounded; callus setae and vertical setae long and slender; callus tubercle short and truncated; antennal ridge conical, darkly sclerotised and anteroventrally directed; antennal sheath slightly tapered with apical tooth; abdominal orbital seta and posterior orbital seta long and slender; lateral orbital seta long and slender, tubercles joined. Thorax. Anterolateral spiracle ( Fig. 10 C) relatively flat; basal alar seta long and slender; anterior mesonotal seta and posterior mesonotal seta, long and slender. Abdomen. Pleural setae long and slender, basal tubercle truncated, unevenly positioned from each other; abdominal segments II–VII with abdominal spiracles anteromedially placed on each pleura; each segment with a spinous fringe of pale spines that are generally straight; segment VIII with 3 combs of setae: dorsal comb 3 robust setae; lateral comb 3–4 slightly weaker setae; ventral comb 5–6 robust setae. Aster ( Fig. 10 D), posterior surface slightly concave, with deep dorsoventrally suture medially; dorsal, lateral and ventral tubercles of aster conical, all tubercles curved towards the posterior, with apices darkly sclerotised, (the tubercle of the aster of D. macrophthalma are exceptionally elongate; see: Fig. 15, English, 1949).

Figures

FIGURE 1. Dasybasis rieki sp. nov. Holotype female (ANIC _ 29: 030321): dorsal view. Scale line = 5 mm.

FIGURE 2. Dasybasis rieki sp. nov. Holotype female (ANIC _ 29: 030321): lateral view. Scale line = 5 mm.

FIGURE 3. Dasybasis rieki sp. nov. Holotype female, (ANIC _ 29: 030321): frontal view of head. Scale line = 5 mm.

FIGURE 4. Dasybasis rieki sp. nov. Holotype female, (ANIC _ 29: 030321): lateroventral view. Scale line = 5 mm.

FIGURE 5. Dasybasis rieki sp. nov. Head morphology; holotype female, (ANIC _ 29: 030321), paratype male (ANIC _ 29: 030324): A, lateral view of head, overall width 4.8 mm; B, antenna male, 1.7 mm; C, antenna female, length 1.9 mm; D, palp female, 2.2 mm; E, palp male, 1.3 mm.

FIGURE 9. Dasybasis rieki sp. nov. A, larva, length 24 mm; B, labium, width 0.15 mm; C, larval head lateral view, length 5.5 mm; D, larval head dorsal view; E, posterior spiracle structure, dorsoventral length 1.6 mm.

FIGURE 10. Dasybasis rieki sp. nov. A, pupa, length 20 mm; B, basal tubercle of setae, basal with 0.2 mm; C, anterolateral spiracle structure, length 1.8 mm: D, aster, width 2 mm.

FIGURES 6 – 8. Dasybasis rieki sp. nov. Paratype male, (ANIC _ 20: 030324) and Paratype female, (ANIC _ 29: 029848). 6: dorsal view of male tergite 9 and cerci. 7: gonocoxites, gonostyli and aedeagus. 8: female terminalia, with spermathecal bulb. Scale line = 0.5 mm