Madagopsina makayensis Feijen, Feijen & Feijen, 2021

Feijen, Hans R., Feijen, Frida A. A., Feijen, Cobi & Gilles, Benoit, 2021, A review of Madagopsina Feijen, Feijen & Feijen (Diptera, Diopsidae) with description of a new species, key to the species, and discussion of intrageneric relationships, ZooKeys 1057, pp. 1-21 : 1

Madagopsina makayensis Feijen, Feijen & Feijen sp. nov.

Figs 3-4 , 5-8 , 10 , 15-17 , 18-22 , 24 , 29 , 30 , 31

Type material.

Holotype, ♂ (RMNH), Madagascar, Makay, canyon, sous-bois, rive d’une rivière [undergrowth, riverbank], 21°10'11"S, 45°22'15"E, 528 m, 30.vii-3.viii.2017, leg. Benoît Gilles.

Diagnosis.

Madagopsina makayensis Feijen, Feijen & Feijen, sp. nov. can be recognised by its medium size (body length ♂ 7.3 mm), brown colour (however, due to conservation in alcohol it is likely that all the brown colours would be more yellowish in a live specimen, like in the other Madagopsina species), body mainly thinly pruinose (pollinose) with few small setulae, only katepisternum and katepimeron glossy, absence of facial teeth, medium-sized inner vertical seta (1.7 × stalk diameter), scutellar spines 2.0 × as long as scutellum, quite large apical seta (45% of scutellar spine length), incrassate fore femora with around 48 tubercles, irrorated wings with three vague crossbands including an H-shaped configuration with central and preapical crossbands, wing apex infuscated, central band slightly broader than preapical band, pale wing spots in cell r2+3 and cell m1, a vague pale spot in cell m4, abdomen club-shaped, no pruinose spots on tergites, ♂ spiracles 7 in slit of synsternite 7+8, surstyli rounded and bulbous with an apically rounded apophysis, microtrichia on posterior apical third, phallapodeme with ratio posterior arm/anterior arm 1.05, straight ejaculatory apodeme with only a slight sickle-shape apically, phallus remarkably broad and sclerotised, assumed moderate sexual dimorphism with regards to eye span (D ≈ 1.0), ratio eye span/body length ~ 1.20 in ♂. Madagopsina makayensis Feijen, Feijen & Feijen, sp. nov. belongs to the M. apollo species group, which furthermore includes M. apollo and M. parvapollina .

Description.

Measurements. Body length ♂ 7.3 mm; eye span 8.8 mm; wing length 5.9 mm; length of scutellar spine 1.01 mm.

Head. Central part brown, ocellar tubercle and arcuate groove dark brown; central head thinly pruinose (Figs 3 - 6 ); an elongate bulbous medial ridge in front of ocellar tubercle, parallel grooves on both sides of this ridge, lateral areas of frons flat; medial occiput flat; face convex in profile, facial corners square, no facial teeth (Figs 5 , 6 ); clypeus small, not protruding; arista finely microtrichose on less than basal half; the rate of dimorphism cannot be calculated, but in the graph (Fig. 31 ) with the allometric lines for the three species of the M. apollo species group it can be seen that the single data point is located in line with the allometric line for M. parvapollina males, while given that the slopes for the females for the species must be almost identical, it follows that D for the new species must be almost identical to the D = 0.98 for M. parvapollina or slightly higher (see also the section "Allometric aspects with regard to eye span" below); eye span large in male (119.6% of body length), also a comparison of this ratio eye span/body length of the single male with the mean ratio eye span/body length of the other Madagopsina species ( Feijen et al. 2018) supports the view that this is a dimorphic species with a moderate rate of dimorphism D ≈ 1.0; stalks thinly pruinose, brown, broad apical parts dark, funiculus brown, pruinose; inner vertical seta medium-sized, 1.7 × diameter of eye stalk (Figs 3 , 5 ), base of inner vertical seta a minor elevation, one-eighth diameter of the stalk; outer vertical seta broken off; central head and stalks with a few tiny white setulae.

Thorax. Collar, scutum, scutellum and postscutellum pruinose, brown (Figs 3 , 4 ), spines glossy; pleura dorsally brownish pruinose, katepisternum and katepimeron largely glossy; ratio scutal length/scutal width ~ 0.80; scutellar spines almost straight, diverging under an angle of ~ 65°, ratio scutellar spine/scutellum in ♂, 2.00, ratio scutellar spine/body length in ♂, 0.14; metapleural spines well developed, pointing almost laterally (Fig. 3 ); apical seta quite large, 45% of length of scutellar spine, posteriorly directed (Figs 4 , 7 , in Fig. 7 the seta is not in its natural, posteriorly directed, position); scutum almost devoid of setulae, scutellar spines with each ~ 10 small setulae, not on warts.

Wing. Irrorated with a rather vague, brownish, H-shaped configuration; apex (8% of wing length) with brownish infuscation (convex on proximal side); 3 crossbands, the basal and central band hardly separated, a pale preapical band and three pale spots (Figs 3 , 10 ); preapical crossband (distal leg of H) broad, marginally darker than other bands and with slightly irregular edges; preapical band connected to central band in cell r1, in cell r4+5 and around veins R2+3 and R4+5; central band slightly broader than preapical band and with ill-defined proximal edge, only in cell m4 vaguely separated from basal band; basal band running from cell c to posterior wing margin, widening posteriorly; this infuscation pattern creates a pale (but not hyaline) preapical band between dark preapical band and infuscated wing apex, two pale spots between central and dark preapical bands (one in cell r2+3 and one in cell m1), and one vague pale spot centrally in cell m4 between basal and central band (Figs 3 , 10 ); glabrous basal areas include basal apices of cell c and cell r1, basal half of cell br, basal quarter of cell bm+dm except for posterior margin and basal third of cell cua; vein M4 reaching to just beyond halfway the wing margin.

Legs. Coxa 1 pale yellowish, glossy but with dense white pruinescence on anterior side, trochanter 1 pale, pruinose; fore femur yellowish brown but dorsally darker, glossy but dorsally and apically pruinose; fore tibia and metatarsus darker brown, other fore tarsi pale and covered with whitish pruinescence; mid- and hind legs more uniformly yellowish, femora pruinose dorsally and with dark brown spot on apical fifth; femur 1 (Figs 3 , 4 ) incrassate in ♂ (ratio of length/width 3.2), two rows of tubercles on distal two-thirds, inner row in ♂ with 25 and 28 tubercles (mean 26.5, n = 2), outer row in ♂ with 21 and 22 tubercles (mean 21.5, n = 2); femur 1 with whitish setulae ventrally.

Preabdomen. Abdomen club-shaped (ratio length/broadest width 2.8); syntergite gradually widening posteriorly, seam between tergites 1 and 2 not visible, suture between tergites 2 and 3 distinct (Fig. 8 ); tergites uniformly yellowish brown (Figs 3 , 8 ), thinly pruinose; syntergite basally with white setulae laterally, otherwise tergites with a few whitish setulae; anterior line-like section (intersternite 1-2) of sternite 2 not linked to main sternite 2 (Fig. 15 ); ratio length sternites 1+2+3/width posterior sternite 2 2.8 in ♂, ratio length/width of sternite 2 1.2 in ♂; sternites very pale, pruinose (except for basal two-thirds of sternite 1); spiracle 1 in tergite (Fig. 15 ).

Postabdomen male. Sternite 4 a rectangular plate; sternite 5 (Fig. 16 ) a rectangular plate, slightly more sclerotised laterally; sternite 6 vague with a pair of small sclerotised sections (Fig. 16 ); synsternite 7+8 quite large, symmetrical, narrowing laterally, lateral slits enclosing hardly sclerotised areas (Fig. 17 ); both spiracles located in the lateral slits of the synsternite (Fig. 17 ); epandrium (Fig. 18 ) rounded, with ~ 11 pairs of setulae, ventrally bare, otherwise clothed in microtrichia; surstyli (Figs 19 , 24 ) articulated, apically broadening, apex rounded and bulbous, with a long, apically broadening and rounded, apophysis; in posterior view (Fig. 24 ) a few small setulae on apical halves of surstylus and apophysis with the apical third of the surstylus and only the apex of the apophysis clothed in microtrichia, on inner side only microtrichia on the apices of surstylus and its apophysis with a few small setulae on apophysis and apical third of surstylus (Fig. 19 ); surstyli interconnected via thin, rod-like processus longi (Fig. 18 ); cerci rather broad, ratio of length/width 1.9, basally and apically tapering, apex rounded, clothed in microtrichia and a set of setulae, some of the apical setulae almost as long as the cerci (Fig. 18 ); hypandrial clasper (Fig. 20 ) straight and rod-like with relatively long setulae on distal half; phallapodeme solidly built and rather straight (Fig. 21 ), anterior arm rounded apically, posterior arm slightly longer than anterior arm (ratio posterior arm/anterior arm 1.05) and strongly bifurcated to accommodate the very broad phallus; phallus (Fig. 21 ) a rather short complex of lobes and sclerites, remarkably broad and heavily sclerotised, intromittent organ very short; ejaculatory apodeme straight, hardly broadening apically except for a small sickle-shape of apex (Fig. 22 ), ejaculatory sac rounded.

Distribution and habitat.

The new species is only known from the Makay massif in Toliara province. The Makay is a mountain range of almost 4000 km2 in southwestern Madagascar. The altitude varies from 200 m at the bottom of canyons to 1000 m for the plateaus. The Makay with its exceptional biodiversity (see Wendenbaum 2011) is considered to be one of the least studied areas in Madagascar. Its forests belong to the deciduous, seasonally dry, western forests of low altitude ( Du Puy and Moat 1999). In the dry season, wet areas remain near the rivers. Many Diopsidae , including aggregations, were observed on vegetation in wet, shady places. The single specimen of this new species was collected in undergrowth along a riverbank at an altitude of 527 m. On the same location the following Diopsidae were collected: 5 ♀ and 5 ♂ Sphyracephala beccarii (Rondani), 5 ♀ and 2 ♂ Diopsis nigrosicus Séguy, and 1 ♂ M. parvapollina .

Etymology.

This species is named M. makayensis Feijen, Feijen & Feijen, sp. nov., referring to the place of origin of the holotype.

Key to the species of Madagopsina

This key is a revised version of the Madagopsina section of the key in Feijen et al. (2018). It now also includes M. makayensis Feijen, Feijen & Feijen, sp. nov. for which only the male is known. The couplet separating the two species groups has been changed to accommodate the new species. In the 2018 key also an error occurred: in the couplet separating M. apollo and M. parvapollina , the character states for the apical seta should have been reversed.

1	Fore femur incrassate in females (ratio length/width 3.4-3.5) and males (ratio length/width 3.2-3.7) (Figs 2 , 4 ), pleurotergal spines laterally directed (Fig. 2 ), dark preapical wing band (width 18-20% of wing length) as broad as central band and equal in colour (Figs 9-11 ), abdomen club-shaped (ratio length/broadest width ≤ 3) (Fig. 8 ), tergites glossy, ratio length sternites 1+2+3/width posterior sternite 2 2.8-3.1, posterior arm of phallapodeme longer than anterior arm (ratio ~ 1.05-1.40) (Fig. 21 )	2 ( Madagopsina apollo species group)
-	Fore femur moderately incrassate to slender in females (ratio length/width 4.6-6.0) and males (ratio length/width 4.6-6.3), pleurotergal spines posterolaterally directed, dark preapical wing band (width 13-14% of wing length) distinctly narrower than central band and darker (Figs 12-14 ), abdomen slender (ratio length/broadest width ~ 4), tergites thinly pollinose with a pair of pollinose lateral spots on tergite 3, ratio length sternites 1+2+3/width posterior sternite 2 4.1-4.8, posterior arm of phallapodeme shorter than anterior arm (ratio ~ 0.71-0.93)	4 ( Madagopsina apographica species group)
2	Large - females on average 9.6 mm (range 8.3-10.2), males on average 9.5 mm (range 8.0-10.1), inner vertical seta 0.8 × stalk diameter, small apical seta (23% of length of scutellar spine), male sternite 5 without combs, apophysis of surstylus short (~ 30% of length of surstylus) and bulbous (Fig. 23 ), subanal plate heart-shaped with bulbous lateral areas	Madagopsina apollo
-	Medium-sized - females on average 6.1 mm (range 5.4-6.8), males on average 6.3 mm (range 5.6-7.0) or just larger to 7.3 mm ( M. makayensis Feijen, Feijen & Feijen, sp. nov.), inner vertical seta 1.6-1.7 × stalk diameter (Figs 1 , 3 ), medium-sized apical seta (37-43% of length of scutellar spine) (Fig. 2 , 7 ), male sternite 5 with or without posterior combs of spine-like setulae, apophysis of surstylus long (> 55% of length of surstylus) and slender (Figs 24 , 25 ), subanal plate triangular (not yet known for M. makayensis Feijen, Feijen & Feijen, sp. nov.)	3
3	Body length of male 7.3 mm, apical seta 45% of length of scutellar spine, anterior central hyaline wing spot in cell r2+3 and not extending into cell r1 (Fig. 10 ), fore femora with ~ 48 tubercles, male sternite 5 without combs, surstylus and its apophysis both apically broadening and rounded (Fig. 24 )	Madagopsina makayensis Feijen, Feijen & Feijen, sp. nov.
-	Body length males on average 6.3 mm (range 5.6-7.0), apical seta on average 37% of length of scutellar spine, anterior central hyaline wing spot in cells r1 and r2+3 (Fig. 11 ), fore femora with ~ 36 tubercles, male sternite 5 with posterior combs of spine-like setulae, surstylus and its apophysis both straight, slender and not apically broadening (Fig. 25 )	Madagopsina parvapollina
4	Inner vertical seta 2.3 × stalk diameter, femur 1 moderately incrassate in females and males (ratio length/width in both sexes 4.6), ratio scutellar spine/scutellum 2.1-2.3, dark preapical wing band rather vague but slightly darker than central band (Fig. 14 ), basal wing band extending through cell br (Fig. 14 ), cell br with microtrichia on apical half, tergite 3 with a pair of tiny posterolateral pollinose spots, surstylus strongly curved (Fig. 28 )	Madagopsina tschirnhausi
-	Inner vertical seta 1.1-1.4 × stalk diameter, femur 1 slender in females (ratio length/width 5.3-5.9) and males (ratio length/width 5.3-6.3), ratio scutellar spine/scutellum 2.5-3.1, dark preapical wing band distinct and much darker than central band (Figs 12 , 13 ), basal wing band not extending anteriorly of vein M1 (Figs 12 , 13 ), cell br with microtrichia only on apical 10%, tergite 3 with laterally a pair of large pollinose spots, surstylus straight (Figs 26 , 27 )	5
5	Inner vertical seta 1.4 × stalk diameter, femur 1 slender in females and males (ratio length/width 5.3), ratio scutellar spine/scutellum 2.9-3.1, preapical dark band uniformly dark, only paler in cell r1 (Fig. 12 ), pollinose spots on tergite 3 posterolaterally located, ♀ sternite 8 divided in two sclerites, apophysis of surstylus less than half the size of central surstylus (Fig. 26 )	Madagopsina apographica
-	Inner vertical seta 1.1 × diameter of stalk, femur 1 very slender in females (ratio length/width 6.0) and males (ratio length/width 6.3), ratio scutellar spine/scutellum 2.5, preapical dark band with distinctly darker spot around vein R4+5 (Fig. 13 ), pollinose spots on tergite 3 mediolaterally located, ♀ sternite 8 a single sclerite, apophysis of surstylus equal in size to central surstylus (Fig. 27 )	Madagopsina freidbergi

Figures

Figure 29. Principal component analysis of wing venation morphometry for the two species of Gracilopsina and six species of Madagopsina: biplot of the first two PCA axes.

Figure 30. Cluster dendrogram for the Euclidian distance in wing morphometry PCA for the Gracilopsina and Madagopsina species using the complete clustering method. Branch labels give the approximately unbiased p - value (AU) and bootstrap probability (BP) values (%).

Figure 31. Eye span plotted against body length for the three species in the Madagopsina apollo species group: M. apollo, M. parvapollina and M. makayensis Feijen, Feijen & Feijen, sp. nov. Note the position of the single data point for the ♂ of the latter species, in line with the ♂ data points for M. parvapollina.

Figures 3 - 4. Madagopsina makayensis Feijen, Feijen & Feijen, sp. nov., ♂, holotype, Makay 3 habitus, dorsolateral view 4 thorax, dorsolateral view. Scale bars: 1 mm.

Figures 5 - 8. Madagopsina makayensis Feijen, Feijen & Feijen, sp. nov., ♂, holotype, Makay 5 head, anterior view 6 central head, anterior view 7 scutellar spine and apical seta, inner view (seta not in natural position in line with spine) 8 abdomen, dorsal view. Scale bars: 1 mm (5); 0.5 mm (6 - 8).

Figures 9 - 11. Madagopsina apollo species group, dorsal view of wings 9 M. apollo, ♂, Ambohitra 10 M. makayensis Feijen, Feijen & Feijen, sp. nov., ♂, holotype, Makay 11 M. parvapollina, ♀, paratype, Ankarana. Scale bars: 0.5 mm. Figures 9, 11 (Feijen et al. 2018, figures 6, 7).

Figures 15 - 17. Madagopsina makayensis Feijen, Feijen & Feijen, sp. nov., ♂, holotype, Makay 15 basal section of abdomen with intersternite 1 - 2, ventral view 16 sternites 5 and 6, ventral view 17 synsternite 7 + 8, ventral view. Scale bars: 0.5 mm.

Figures 18 - 22. Madagopsina makayensis Feijen, Feijen & Feijen, sp. nov., ♂, holotype, Makay 18 epandrium with surstyli and cerci, posterior view 19 surstylus, inner view 20 hypandrial clasper, lateral view 21 phallapodeme and phallus, lateral view 22 ejaculatory apodeme and sac. Scale bars: 0.5 mm (18, 21); 0.1 mm (19, 20, 22).

Figures 23 - 28. Posterior view of Madagopsina surstyli 23 - 25 M. apollo species group 26 - 28 M. apographica species group 23 M. apollo 24 M. makayensis Feijen, Feijen & Feijen, sp. nov. 25 M. parvapollina 26 M. apographica 27 M. freidbergi 28 M. tschirnhausi. Scale bar 0.1 mm (all drawn to the same scale). Figures 25 - 28 (Feijen et al. 2018, figures 187, 184, 186, 188).

Figures 1 - 2. Madagopsina parvapollina, live photographs by Gernot Kunz, Mahajanga, Boeny (www. inaturalist. org / observations / 20766277) 1 anterior view 2 dorsal view.

Figures 12 - 14. Madagopsina apographica species group, dorsal view of wings 12 M. apographica, ♀, Fianarantsoa 13 M. freidbergi, ♀, paratype, Vohimana 14 M. tschirnhausi, ♂, holotype, Mount Ambre. Scale bars 0.5 mm. Figures 12 - 14 (Feijen et al. 2018, figures 8 - 10).