Bioacoustics of Porophila chakalaka

Description. Body of male ( Fig. 1 ) and female ( Figs 2–3 ) elongate and weakly convex, suboval; pigmentation light to moderately dark brown with appendages yellowish brown, vestiture of setae yellowish; BL female: 0.61–0.68 mm (mean 0.64 mm ); BL male 0.58–0.68 mm (mean 0.63 mm ). Head ( Figs 1–5 ) broadest at large, strongly convex and coarsely faceted eyes, HL female 0.06–0.08 mm (mean 0.07 mm ), HW female 0.15–0.18 mm (mean 0.16 mm ); HL male 0.07–0.08 mm (mean 0.07 mm ), HW male 0.15– 0.18 mm (mean 0.15 mm ). Vertex and posterior region of frons evenly convex, anterior region of frons steeply lowering anterad; supraantennal tubercles not marked. Punctures on frons and vertex fine and sparse, inconspicuous, so that head appears glossy ( Fig. 1 ); only several short and suberect setae are distributed on head dorsum. Antennae ( Fig. 6 ) short in relation to body; AnL female 0.15–0.16 mm (mean 0.15 mm ); male 0.15–0.18 mm (mean 0.17 mm ); scape and pedicel each large and subcylindrical, elongate, antennomere 3 distinctly elongate and narrowing toward apex (in dry-mounted specimens partly sunken into apical portion of pedicel and only its distal half visible, as in Fig. 6 ), antennomere 4 elongate, narrower than 3 at base and about equally long as 3, antennomere 5 slightly elongate, indistinctly longer but clearly broader than 4, antennomere 6 indistinctly broader but clearly shorter than 5, distinctly transverse, antennomere 7 slightly broader and longer than 6, transverse, antennomere 8 slightly broader but shorter than 7, strongly transverse, antennomere 9 distinctly broader and longer than 8, transverse, antennomere 10 distinctly broader and much longer than 9, about as long as broad, antennomere 11 about as broad as 10 but distinctly longer, 1.8 × as long as broad; all antennomeres with sparse, long setae, 10 and 11 additionally with long digitiform sensilla. Postocular ventral region of head ( Fig. 5 ) covered with transverse microreticulation; submentum ( Fig. 7 ; smn ) short and strongly transverse, with a pair of submedian setae; mentum ( Fig. 7 ; mn ) subtriangular with anterior margin broadly rounded, with three pairs of lateral setae, in resting position its anterior margin interlocking with ventrally tilted labrum, which bears 10 pairs of lateral setae of various lengths; cardo ( Fig. 7 ; cd ) short and broad, with one median basal seta; basistipes ( Fig. 7 ; bst ) subtriangular, broader than long, with two setae; palpifer ( Fig. 7 ; ppf ) as broad as basistipes, with one lateral subapical seta; lacinia and galea ( Fig. 7 ; lac , gal ) elongate, each with a robust apical brush of short, thick setae; maxillary palps ( Fig. 7 ; mxp ) with elongate palpomere 1, distinctly broadened and elongate palpomere 2, large, suboval palpomere 3, and strongly elongate, slender, nearly rod-like palpomere 4. Prementum and labial palps not observable in studied specimens, covered by labrum. Pronotum ( Figs 1–4 ) nearly semicircular, broadest at base; PL female 0.14–0.18 mm (mean 0.15 mm ), PW female 0.20–0.25 mm (mean 0.22 mm ); PL male 0.13–0.16 mm (mean 0.15 mm ), PW male 0.20–0.24 mm (mean 0.22 mm ). Anterior and lateral margins confluent and broadly rounded; lateral margins forming complete, sharp lateral carinae, with a broadening near middle bearing opening of prothoracic gland ( Fig. 4 ; pgo ); posterior corners in dorsal view sharp-angled and distinctly projecting posterad; posterior margin evenly convex at middle and distinctly concave near posterior corners. Punctures on pronotal disc much denser than those on head, in posterior half large but shallow, with their anterior and lateral margins distinct, but posterior margins obliterated, punctures along posterior margin arranged in two parallel and slightly irregular rows, punctures on anterior 2/3 fine, lacking sharply marked margins; setae dense, short, slightly suberect. Prosternum ( Fig. 5 ; pst ) much shorter than procoxae and laterally fused with concave hypomera ( Fig. 5 ; hy ); prosternal process subtriangular and not separating procoxae; posterior margin of prosternum ( Fig. 8 ) with large subtriangular emargination. Hypomera microreticulated. Fore legs with oval procoxae bearing several setae and microreticulated; protrochanters elongate, each with one subapical and one posterior seta; profemora fusiform, with ventral surface concave to receive tibia, sparsely setose and dorsally and laterally microsculptured; protibiae short and distally distinctly thickened, each with several apical and subapical thickened setae and several thin setae on remaining surface; protarsi slender. Mesonotum ( Figs 9–10 ) with transverse, subrectangular mesoscutum ( Fig. 10 ; sc2 ) and large, triangular mesoscutellum ( Fig. 10 ; scl2 ) delimited on ventral surface by transverse scutoscutellar suture ( Fig. 10 ; sss ); dorsal surface of scutellar shield with only partly distinct scale-like miscrosculpture and dense, short setae. Elytra ( Figs 1–3 , 11–12 ) together oval, elongate, slightly broader than pronotum, broadest between middle and anterior third; EL female 0.39–0.43 mm (mean 0.41 mm ), EW female 0.25–0.28 mm (mean 0.25 mm ), EI female 1.55–1.72; EL male 0.38–0.45 mm (mean 0.41 mm ), EW male 0.25–0.28 mm (mean 0.25 mm ), EI male 1.43–1.70. Each elytron with tiny, barely discernible humeral denticle; surface with indistinct scale-like microsculpture and dense, short, weakly suberect setae similar to those on pronotum. Ventral surface of elytron ( Fig. 11 ) lacking stridulatory field; ventral apical region ( Fig. 12 ) irregularly microserrate, laterally with a row of dense trichia. Mesoventrite ( Figs 15–16 ) strongly transverse, with narrow prepectus. Mesoventral process ( Figs 1 , 5–16 ; msvp ) anteriorly continuous with prepectus, slightly constricted near middle, narrowing posterad to triangular apex between mesocoxae, with median longitudinal carina in anterior half and with a group of setae on posterior, triangular region. Lateral regions of mesoventrite slightly concave; entire surface of mesoventrite microreticulate. Middle legs with oval coxae bearing a few setae and with microreticulate surface; mesotrochanters subtriangular, weakly elongate, each with a few setae; mesofemora fusiform, flattened, with indistinct microreticulation and sparse setae; mesotibiae slightly broadening distad, sparsely covered with setae and with apical and subapical bristles; mesotarsi slender. Metanotum ( Fig. 9 ) dominated by large metascutellum ( Fig. 9 ; scl3 ) reaching to middle of abdomen, with sharply serrate lateral margins in distal half; alacristae with elongate scale-like microsculpture. Metathoracic wing ( Figs 13–14 ) long, with narrow blade and long ‘feathers’. Metaventrite ( Figs 15–16 ) distinctly transverse and weakly convex, with metaventral lines ( Figs 15–16 ; mtvl ) extending from lateral margin of each mesocoxal cavity and converging posterad to reach metaventral process, each line slightly sinuate; metaventral process composed of a pair of long, slender spines. Entire surface of metaventrite covered with indistinct scale-like microsculpture and with evenly distributed, short and dense, nearly recumbent setae. Hind legs with large, transverse and weakly convex coxae, each bearing two complete rows of long setae: transverse submedian row parallel to anterior coxal margin and oblique posterior row parallel to posterior coxal margin; metatrochanters largely hidden under coxal plates, subtriangular with posterior margin rounded, each with several setae; metafemora flattened, shorter than mesofemora, covered with indistinct microsculpture and with several long setae in distal half of ventral surface; metatibiae shorter than mesotibiae, brodest near middle and strongly narrowing in distal half, with surface covered with long setae and with several shorter and thicker setae on mesal margin in distal third; metatarsi slender. Abdomen ( Figs 9 , 15, 17 , 22 ) about as long as metaventrite (in specimens preserved in ethanol swollen and slightly longer than metaventrite). Tergite I large and asetose; tergites II–IV gradually reducing in length, each with one row of setae (short and thin on tergites II–III, distinctly longer and thicker on IV) along posterior margin and with distinct lateral rows of arcuate strigulae ( Fig. 9 ; str ); tergites V–VI each with one row of long and thick setae along posterior margin; tergite VII with median transverse row of long and thick setae and with wing folding fringe (palisade fringe of Sörensson (1997)) of thick and dense trichia ( Fig. 9 ; wff ); tergites VIII and IX each much longer than preceding tergites, with postmedian (VIII) or median (IX) transverse row of long and thick setae and another row of similar setae along posterior margin; tergite X (pygidium) with dense scaly punctures (with arcuate posterior margins distinct and anterior margin obliterated) and dense setae on entire exposed surface, pygidial apex ( Fig. 17 ) with a pair of robust lateral spines connected by short subtrapezoidal lamina. Sternite III (first visible) about as long as IV–V together, with a pair of straight, posteriorly diverging median femoral lines ( Figs 15–16 ; mfl ), all sternites with one transverse row of long setae along posterior margins, on sternite III row of setae incomplete, interrupted behind coxae ( Fig. 16 ). Aedeagus ( Figs 18–21 ) strongly elongate; AeL 0.13 mm ; median lobe slightly broadening from base to subapical region, where it is rapidly narrowed forming elongate, subtriangular apical projection with rounded apex; in lateral view aedeagus nearly straight, with narrow apical region. Spermatheca ( Figs 22–23 ) with vesicular part slightly asymmetrical, 0.03 mm in length, pump short and with its funnel-like portion only slightly narrower than vesica; ductus spermathecae short, with strongly and gradually broadened insertion to vesica. Sexual dimorphism. Weakly marked only in indistinctly different measurements: females are on average slightly larger and with slightly shorter antennae in relation to body, but measurements of large males and small females overlap. Variability. Proportions of elytra are most variable measurements among the studied specimens, with EI between slenderest and stoutest specimens differing by ∼ 11% in females and ∼ 19% in males.