Sphyracephala munroi Curran, 1928

Feijen, Hans R., Feijen, Frida A. A. & Feijen, Cobi, 2025, A revision of the four Afrotropical and Palaearctic Sphyracephala Say (Diptera, Diopsidae) with an illustrated overview of the other five Sphyracephala, ZooKeys 1241, pp. 1-81 : 1-81

Sphyracephala munroi Curran, 1928

Figs 1 , 3 , 54–56 , 57–59 , 60 , 61–65 , 66–71 , 72–77 , 105 , 106 , 107 , 108 , 109 , 110–112 , Tables 2 , 3 , 4

Sphyracephala munroi Curran, 1928: 274. Séguy 1949: 75, 1955: 1124; Collart 1954: 330; Descamps 1957: 17; van Bruggen 1961: 415, figs 13, 14, 16; Lindner 1962: 18; Trân 1975: 14, fig. 22 b; Cogan and Shillito 1980: 584; Arnaud and Owen 1981: 144; Feijen 1989: 21; Rossi 1990: 3; Baker 1999: 15, figs 1-2, 1-3, 1-7, 2-2, 2-3, table 2-1, App. A; Hariri et al. 1998: 255, table 1; Baker and Wilkinson 2001: figs 2, 3, table 1; Baker et al. 2001: figs 1, 2, table 1; Meier and Baker 2002: fig. 2; Camerik 2006: 140, table 7; Voje and Hansen 2013: figs 1, 2, tab 1; Husak et al. 2013: fig. 2; Holstein 2015: fig. 2 on page 159 (not identified as S. munroi); Feijen and Feijen 2021: 1540, fig. 64.27.

Sphyracephala beccarii (Rondani): Séguy 1949: 75. Collart 1954; 329;

Sphyracephala munroi, Austen in Brunetti, 1928: 273. Nomen nudum.

Type series.

South Africa: holotype, ♀, Farm Stentor, Barberton, Transvaal [Mpumalanga province, Ehlanzeni District, Nkomazi Local Municipality , 25°33'6"S, 31°22'42"E, 390 m], 7.vi.1925, H. K. Munro ( NMSA) .

Material studied.

Kenya: 5 ♀, 2 ♂, Mt. Elgon , E. side Kaptega r. [~ 1°11'22"N, 34°45'44"E, ~ 2250 m], 26.i.1975, T. Kronestedt ( NHRS) ; Malawi: 24 ♀, 37 ♂, Nyika , Mondwe valley [10°24'S, 33°50'E, 1760 m], vii.1972, D. Munthali ( RMNH) ; 3 ♀, Zomba, near postoffice [15°22'30"S, 35°19'32"E, 980 m], 18.xi.1973; 3 ♂, 25.xi.1973; 9 ♀ 13 ♂, 27.x.1974, all H. R. Feijen ( RMNH) ; 1 ♂, Zomba, Mlunguzi river , [15°22'30"S, 35°19'18"E, 1140 m], 2.viii.1975; 1 ♀, 7.viii.1975, all H. R. Feijen ( RMNH) ; 1 ♂, Mulanje, Likabula river [15°56'19"S, 35°31'13"E, 1045 m], 5.viii.1974, H. R. Feijen ( RMNH) ; 2 ♀, 3 ♂, Fort Lister , along small river [Phalombe District, 15°49'58"S, 35°40'23"E, 1005 m], 5.viii.1974, H. R. Feijen ( RMNH) ; Tanzania: 10 ♀, 19 ♂, Marangu [3°16'35"S, 37°31'11"E, 1480 m], 30.vi.1978, H. R. Feijen ( RMNH) ; 8 ♀, 13 ♂, Arusha [3°22'15"S, 36°41'48"E, 1400 m], 8.vii.1978; 3 ♀, 2 ♂, 3.viii.1978; 242 ♀, 210 ♂, 9.xi.1978; 1 ♂, 4.vii.1987, all H. R. Feijen ( RMNH) ; 10 ♀, 1 ♂, Arusha Centre [3°22'15"S, 36°41'48"E, 1400 m], 8.viii.1978, H. R. Feijen ( RMNH) ; 1 ♂, Arusha, Mnt Meru hotel [~ 3°21'59"S, 36°42'14"E, 1430 m], 10.ii.1984, G. G. M. Schulten ( RMNH) ; Uganda: 1 ♀, Bundibugyu distr., River Kyemahizi , 0°40'12"N, 30°02'06"E, 920 m, 19.3.2012, M. von Tschirnhaus ( FBUB) . In total 318 ♀ and 307 ♂ were examined, giving a balanced sex-ratio of 100 ♀: 97 ♂ (see also Table 4 ).

Diagnosis.

Sphyracephala munroi can be recognised by the following set of characters: head, thorax and abdomen blackish; overall covered with long setulae; brown band below arcuate groove, large brown spots on occiput; eye stalk stout (~ 0.7 × the widest sagittal eye diameter), comparatively long and straight for a Sphyracephala ; very small eye span (2.5–2.7 mm) in ♀ and ♂ (respectively ~ 61 % and ~ 67 % of body length); very low rate of dimorphism D = 0.33; rectangular basiliform prosternum; apical seta / scutellar spine ratio: ~ 6.1; scutellar spine / scutellum ratio: 0.44; very small, blackish scutellar spines ~ 0.13 mm; transparent wings with brownish tinge; brown fore femur with apical third dark brown, inner side with dark brown longitudinal stripe on central third, incrassate (l / w ratio: 3.63), with two rows of transparent slender spinous setae, inner row with ~ 2.8 setae, outer row with ~ 4.0 setae; tergite 1 with fine transverse ridges and deep circular groove; intersternite 1-2 mesally a small dark sclerite, laterally narrowly connected to main sternite 2; ♀ tergite 7 with 2 large, rectangular sclerites; ♀ sternite 7 forming two rectangular sclerites with posterior extensions; ♀ cerci elongate, l / w ratio: ~ 4.6; ♀ sternite 8 forming two large rectangular sclerites; no real sclerotised ring, but mesally a tiny structure with thin lateral extensions; surstyli articulate, ventromedially directed, parallel-sided, on medial side hollow, no microtrichia, outer side clothed in setulae, inner side with a comb of fine, small setulae. Sphyracephala munroi belongs to the S. brevicornis species group and comes closest to S. babadjanidesi .

Redescription.

The following redescription considers the original description by Curran (1928), the table of differences between S. beccarii and S. munroi by Collart (1954), and description and illustrations by van Bruggen (1961: figs 13, 14, 16).

Measurements. Body length ♀ 4.2 mm ± SE 0.0 (range 3.7–4.7, n = 40), ♂ 4.1 mm ± 0.0 (range 3.7–4.5, n = 40), eye span ♀ 2.5 mm ± 0.0 (range 2.2–3.0, n = 40), ♂ 2.7 mm ± 0.0 (range 2.2–3.2, n = 40); wing length ♀ 3.5 mm ± 0.0 (range 3.2–3.7, n = 10), ♂ 3.6 mm ± 0.1 (range 3.3–3.8, n = 10); length of scutellar spine ♀ 0.13 ± 0.00 (range 0.10–0.14, n = 10), ♂ 0.13 mm ± 0.00 (range 0.12–0.14, n = 10). Baker and Wilkinson (2001) found ♀ mean body length 5.96 mm, ♂ 5.29 mm, ♀ mean eye span 2.88 mm, ♂ 2.86 mm.

Head. Central head (Figs 54 – 58 ) and stalks blackish brown with broad brown band below arcuate groove running from antenna to antenna, basal ventral sections of stalks brown, occiput yellowish brown with dark brown edges; head uniformly pruinose (Figs 57 , 58 ) except for glossy ventral part of clypeus and glossy ventral edge of occiput, head quite setulose; arcuate groove not very distinct, narrow and blackish; frons with slight elevation below ocellar tubercle; face flat, no facial teeth, lateroventral corners rounded, facial sulcus absent, but ventral facial edges slightly turned upward medially; eye stalk stout, ~ 0.7 × the widest sagittal eye diameter; eye span very small in both female (61.3 % ± SE 0.2 % of body length, n = 40) and male (66.7 % ± SE 0.5 % of body length, n = 40); a dimorphic species with a very low rate of dimorphism D = 0.33 (Figs 60 , 105 , 106 , Table 2 ); inner vertical seta long, close to 0.5 mm, 1.5 × diameter of eye stalk; outer vertical seta long, close to 0.4 mm, 1.1 × diameter of eye stalk (Figs 57 , 58 ). Curran (1928) indicated long ocellar setae, but that must be an error. Baker and Wilkinson (2001) found eye span in female to be 48.3 % of body length and in male 54.1 %, whereas they found a rate of dimorphism of 0.18 which would indicate S. munroi as a monomorphic species.

Thorax. Collar blackish, pruinose; scutum, scutellum and scutellar spines uniformly blackish, pruinose and quite setulose (Fig. 56 ) [ Curran (1928) described the scutellar spines as brown, but Collart (1954) and van Bruggen (1961) named the black spines a differential character]; pleura blackish, uniformly pruinose; posterior notopleural seta medium-sized; infra-alar seta long, 3 × the length of notopleural seta (Fig. 56 ); supra-alar carina distinct; basiliform prosternum (Fig. 1 ) large, rectangular, laterally close to propleuron but clearly distinct [ Feijen (1989) noted a precoxal bridge for S. munroi , but that is an error.]; scutal length / scutal width ratio: 0.87; scutellum trapezoid, strongly narrowing distally; scutellar spines very small, straight, slightly turned upward, diverging at angle of ~ 75 °; scutellar spine / scutellum ratio: 0.44 ± 0.01 (n = 20, see Table 3 ); scutellar spine / length of body ratio: 0.033 ± 0.001 (n = 20); apical seta / scutellar spine ratio: 6.10 ± 0.12 (n = 19); scutellar length / scutellar width (at base) ratio: 0.60 ± 0.01 (n = 20).

Wing. Transparent with a faint brownish tinge, especially apically (Figs 56 , 59 ); vein CuA + CuP from vein CuP onward extending under angle of 45 ° to halfway wing margin in straight line; vein M 4 continuing distal of crossvein dm-m to one third of distance to wing margin; cell cua narrow, basally acute, apically rounded (Fig. 59 ); crossvein h distinct; glabrous area only includes anterior half of cell bc.

Legs. Fore coxa and trochanter pale brown (Fig. 63 ), coxa densely pruinose on anteriorly directed side, setulose; fore femur (Figs 61–63 ) pale brown, apical third dark brown on inner and outer side, inner side with characteristic dark brown longitudinal stripe on central third (Fig. 61 ), outer side thinly pruinose, inner side with subapically a densely pruinose depression, thinly pruinose dorsally and on inner side, clothed in pale setulae; fore tibia and tarsus dark brown, thinly pruinose and with rows of blackish setulae; mid and hind legs pale brown, femora with dark brown apical third, tibiae and tarsi brown; fore femur incrassate (Table 2 ), l / w ratio: 3.63 ± SE 0.06 in ♀ (n = 10) and 3.63 ± 0.03 in ♂ n = 10); fore femur with two rows of rather transparent, slender spinous setae (almost setula-like and difficult to count, especially on inner side) on distal half with in ♀ 6.0 ± SE 0.4 setae (n = 12) and in ♂ with 7.2 ± 0.3 (n = 12), inner row with 2.8 ± 0.1 (n = 24) setae and outer row with 4.0 ± 0.1 setae (n = 24), two rows of tubercles on distal three-quarters (Fig. 63 ) with in ♀ 46.5 ± 0.8 tubercles (n = 11) and in ♂ with 44.5 ± 0.6 (n = 11), inner row with 24.2 ± 0.3 (n = 23) tubercles and outer row with 21.3 ± 0.3 (n = 23) tubercles.

Curran’s (1928) key separating S. beccarii from S. munroi by the “ Tibiæ and tarsi largely or wholly yellowish ” for the former and the tibiae and tarsi brown for the latter should be disregarded. Collart (1954) in his tabulated key indicated useful differential characters: for S. beccarii “ Fémurs antérieurs: fortement grossis. Tibias postérieurs: noirs à l’extrémité seulement. ” and for S. munroi “ Fémurs antérieurs: modérément épaissis. Tibias postérieurs: entièrement noirs. ”

Preabdomen. Tergites (Fig. 64 ) blackish brown, very thinly pruinose, almost glossy, setulose, especially laterally; tergite 1 with fine transverse ridges and on the meson a large, deep, circular groove (Fig. 64 ); suture between tergites 1 and 2 visible; tergites 2–6 rectangular; sternites 1–6 brown, all covering the width of the abdomen, clothed in small white setulae, sternites 1 and 2 glossy, sternites 3–6 thinly pruinose; sternite 1 short and trapezoid (Figs 65 , 70 ); intersternite 1-2 mesally a slender dark sclerite, laterally narrowly connected to main sternite 2; sternites 2–5 rectangular sclerites (Figs 65 , 66 ); sternite 6 consisting of two long, elongate sclerites, posteriorly with less sclerotised, narrower extensions (Fig. 66 ).

Female postabdomen. Postabdomen long, narrow (Fig. 66 ); tergite 7 represented by two rectangular sclerites, well separated mesally; tergite 8 two rectangular, thinly pruinose, sclerites, separated on the meson; tergum 10 short, posteriorly rounded, thinly pruinose but laterally glabrous, one pair of apical setulae; cerci elongate, l / w ratio: ~ 4.6, clothed in microtrichia and setulae (Fig. 67 ); sternite 7 consisting of two rectangular, elongate sclerites with long, narrow posterior extension; spiracle 7 in membrane; sternite 8 represented by two large rectangular sclerites, separated on the meson, almost taking up the width of the abdomen, posterolaterally more sclerotised (Fig. 3 ), clothed in microtrichia and 12 pairs of setulae; subanal plate (Fig. 69 ) pentagonal with rounded corners, apex with one pair of longer setulae, clothed in microtrichia and a few pairs of small setulae; spermathecae (Fig. 71 ) mushroom-shaped with medium-sized, bell-shaped, hollow, more sclerotised, striated, inner structure, no protuberances; no real sclerotised ring of ventral vagina, but mesally a tiny curved structure with thin lateral extensions with a very thin, transparent connection between posterior tips (Fig. 68 ).

Male postabdomen. Syntergosternite 7 + 8 slender, on both sides extending on the venter, (Fig. 77 ), spiracles 7 connected to sclerite well before its apices; epandrium (Fig. 72 ) rounded, clothed in microtrichia and ~ 25 pairs of setulae; surstyli (Figs 73 , 74 ) articulate, l / w ratio: ~ 2.8, ventromedially directed, almost parallel-sided, apically rounded, on medial side hollow (scoop-like), no microtrichia, outer side clothed in setulae on distal three-quarters (Fig. 73 ), inner side with a few larger setulae on distal half, a comb of fine, small setulae along central ridge of “ scoop ” (Fig. 74 ); surstyli interconnected via slender processus longi; cerci (Fig. 72 ) broadening towards apex, length / broadest width ratio: 1.6, clothed in microtrichia and ~ 20 setulae; phallapodeme (Fig. 76 ) with club-shaped anterior arm, apically rounded, anterior arm 1.5 × longer than posterior arm, lateral processes broad; phallus broad, short, male genital process hardly sticking out from apex; ejaculatory apodeme straight, slender, apically twice as broad as basally (Fig. 75 ), ejaculatory sac normal-sized.

Biology.

Compared with S. beccarii , not much is known about the second Afrotropical species S. munroi . The large numbers of flies collected in Arusha, Tanzania, clearly show that S. munroi can also show gregarious behaviour. However, real clusters (see Feijen et al. 2017) have not yet been reported. Rossi (1990) described Stigmatomyces beccarii ( Laboulbeniales ) from S. beccarii , while Stigmatomyces elongatus was described from S. munroi . Both new fungi were described from flies from Malawi. It is interesting to note that these Sphyracephala were parasitised by very different Stigmatomyces . Hariri et al. 1998 recorded the presence of bacteria Type A Wolbachia in S. munroi . Wolbachia can be associated with female-biased sex ratio distortion, but such a sex ratio has not been found in S. munroi (Table 4 ). Feijen (1989) reported on a S. munroi with the venter covered with closely packed mites. In the specimens examined, 3 ♀ and 1 ♂ from 9. xi. 1978, Arusha, had the venter covered with mites. Camerik (2006) described the mite Pediculaster kilimanjarensis (Acari: Siteroptidae ) from S. munroi collected in Tanzania.

Distribution.

Angola, D. R. Congo, Eswatini, Kenya, Malawi, Mozambique, South Africa, Tanzania, Uganda, Zimbabwe. It appears that S. munroi is confined to Eastern and Southern Africa. However, we have seen some records from West Africa, but those need confirmation. Sphyracephala munroi was, in general, only collected from higher altitudes of 900–2250 m. Only the type locality in South Africa is from a lower altitude (390 m).

Figures

Figure 60. Sphyracephala munroi, eye span plotted against body length.

Figure 105. Eye span plotted against body length for males of eight Sphyracephala species. A single data point for S. nigrimana is also shown.

Figure 106. Eye span plotted against body length for females of eight Sphyracephala species. A single data point for S. nigrimana is also shown.

Figure 107. Geometric morphometric PCA analysis of Sphyracephala wing venation patterns. Grey dots represent landmarks that were placed with the aid of straight (dotted) lines through other landmarks (white dots). Asterisks indicate wings from paratypes of S. europaea (junior synonym of S. babadjanidesi).

Figure 108. Hierarchical clustering analysis of principal component scores from the PCA in Fig. 107, using the average clustering method. Branch labels indicate the Approximately Unbiased p-value (AU) and Bootstrap Probability (BP). Asterisks indicate wings from paratypes of S. europaea (junior synonym of S. babadjanidesi).

Figure 109. Hierarchical clustering analysis of principal component scores from the PCA in Fig. 107, using the complete clustering method. Branch labels indicate the Approximately Unbiased p-value (AU) and Bootstrap Probability (BP). Asterisks indicate wings from paratypes of S. europaea (junior synonym of S. babadjanidesi).

Figures 1, 2. Prosternum, ventral view 1 basiliform prosternum, ♂, Sphyracephala munroi, Arusha, Tanzania 2 precoxal bridge, ♂, Sphyracephala beccarii, Mboma, DR Congo. Scale bars: 0.1 mm.

Figures 3, 4. ♀, sternite 8, ventral view 3 Sphyracephala munroi, Arusha, Tanzania 4 Sphyracephala beccarii, Maputo, Mozambique. Scale bars: 0.1 mm.

Figures 54–56. Sphyracephala munroi, 54, 55 live photographs 54 Arusha N. P., Tanzania (photograph © Donyo Gabriel) 55 Matema, Tanzania (photograph © Martin Grimm) 56 ♀, Arusha, Tanzania, habitus, dorsal view. Scale bar: 1 mm (56).

Figures 57–59. Sphyracephala munroi 57 ♀, head, anterior view, Zomba, Malawi 58 ♂, head, anterior view, Arusha, Tanzania 59 ♀, wing, Arusha. Scale bars: 0.5 mm.

Figures 61–65. Sphyracephala munroi, ♀, 61, 62 Marangu, Tanzania 63–65 Arusha, Tanzania 61 fore femur, inner view 62 fore femur, outer view 63 fore legs, lateral view 64 abdomen, dorsal view 65 abdomen, ventral view. Scale bars: 0.5 mm (64, 65); 0.2 mm (61–63).

Figures 66–71. Sphyracephala munroi, ♀, 66, 68–70 Arusha, Tanzania, 67, 71 Zomba, Malawi 66 postabdomen, ventral view 67 tergite 8, 10 and cerci, dorsal view 68 sclerotised ring 69 subanal plate, ventral view 70 sternite 1, intersternite 1-2 and sternite 2, ventral view 71 spermathecae. Scale bars: 0.2 mm (66, 70); 0.1 mm (67, 69, 71); 0.05 mm (68).

Figures 72–77. Sphyracephala munroi, ♂, Zomba, Malawi 72 epandrium, cerci, surstyli, posterior view 73 surstylus, outer view 74 surstylus, inner view 75 ejaculatory apodeme + sac 76 phallapodeme 77 syntergosternite 7 + 8, posterior view. Scale bars: 0.1 mm.

Figures 110–112. 110 Cladogram of Sphyracephala species groups according to Feijen (1989) 111 preferred maximum likelihood phylogeny of the Sphyracephalinae, based on molecular analysis (Jackson 2019, supplemental figure 1, in slightly adapted form). Numbers at nodes represent Ultrafast Bootstrap supports 112 revised cladogram of Sphyracephala species groups.