Eremohaplomydas whartoni, Boschert & Dikow, 2022

Boschert, Claire & Dikow, Torsten, 2022, Taxonomic revision of the mydas-fly genera Eremohaplomydas Bequaert, 1959, Haplomydas Bezzi, 1924, and Lachnocorynus Hesse, 1969 (Insecta, Diptera, Mydidae), African Invertebrates 63 (1), pp. 19-75 : 19

Eremohaplomydas whartoni sp. nov.

Figs 19-24 , 25-30 , 34 , 57

Diagnosis.

The species is distinguished from congeners by the overall light brown colouration, the reduced alula on the wing, the apubescent abdominal tergites 5-8 in females, and the restricted distribution in the central Namib Desert.

Etymology.

This species is named after Dr Robert Wharton, the only collector of this species, in recognition of his year-long seminal study of the Mydidae (and other taxa) of the central Namib Desert at the Gobabeb Namib Research Institute in 1978-1979 ( Wharton 1982). The specific name is to be treated as a noun in apposition.

Description.

Female. Head: black, facial gibbosity light brown, in general grey pubescent, white setose, regular, cylindrical setae; width distinctly greater than thorax (at postpronotal lobe), interocular distance on vertex same as at ventral eye margin; vertex between compound eyes ± horizontally straight, medially only slightly below dorsal eye margin, vertex grey pubescent, white setose; ocellar triangle apubescent; facial gibbosity distinct, well-developed and discernible in lateral view, mystax covering entire facial gibbosity, white; parafacial area more than ½ width of central facial gibbosity (at same level); frons not elevated, grey pubescent, white setose; occiput grey pubescent, white setose, median occipital sclerite light brown macrosetose; pocl macrosetae absent; postgena sparsely grey pubescent, long, sparsely white setose; clypeus comprised of single sclerite, entirely sclerotized medially, flat to protruding (convex) ventrally, ventrally expanded, anterior to proboscis (almost covering it), laterally connected to face by sclerotized cuticle; proboscis very short, vestigial, knob-like, brown; labellum indiscernible, length indiscernible, sclerotization indiscernible; maxillary palpus cylindrical, light brown, minute.

Antenna: light brown to brown; scape asetose; pedicel white setose dorsally and ventrally; postpedicel cylindrical in proximal ¼, symmetrically bulbous in distal ¾, ≥ 5.0 times as long as combined length of scape and pedicel, asetose; apical seta-like sensory element situated apically in cavity on postpedicel.

Thorax: dark brown, predominantly grey pubescent; scutum uniformly black, surface microrugose (slightly rugose ‘imitating’ pubescence), predominantly grey pubescent, broad sublateral stripes (interrupted by transverse suture) sparsely grey pubescent, narrow paramedian stripes merging postsuturally and not reaching posterior margin sparsely grey pubescent, scutal setation comprised of long white setae in pubescent areas; dc setae pre- and postsuturally white, acr setae absent, lateral scutal setae white, npl setae 0, spal setae 0, pal setae 0; proepisternum apubescent medially, grey pubescent laterally, long yellowish macrosetose; proepimeron grey pubescent, asetose; antepronotum antero-medially smooth (without any indentation); lateral postpronotum long white setose; postpronotal lobe yellow, grey pubescent, short yellowish setose; scutellum grey pubescent, discal scutellar setae absent, apical scutellar setae absent; mesopostnotum grey pubescent, asetose; anatergite grey pubescent, asetose; katatergite grey pubescent, long white setose, elevated and smoothly convex; anepisternum grey pubescent, anteriorly asetose, posteriorly asetose, otherwise asetose; katepisternum sparsely grey pubescent, asetose; anepimeron sparsely grey pubescent, asetose; katepimeron sparsely grey pubescent, asetose; meron sparsely grey pubescent, asetose; metakatepisternum large; metanepisternum grey pubescent, asetose; metepimeron light brown (same color as T1), grey pubescent, long yellowish setose, ± flat, infra-halter sclerite absent.

Legs: yellow to brown, setation comprised of white setae, yellow macrosetae; pro coxa sparsely grey pubescent, short white macrosetose; mes coxa sparsely grey pubescent, short white setose and macrosetose; met coxa laterally unsclerotized (membrane between coxa and metakatepisternum clearly visible), sparsely grey pubescent, short white setose and macrosetose; met trochanter setose medially; pro + mes femur yellow to light brown, met femur light brown to brown, distinctly clubbed for nearly entire length, macrosetose with thickened spine-like macrosetae on protuberances in 1 antero-ventral and 1 postero-ventral rows, 2-3 macrosetae distally in anterior row, postero-ventrally sparse, short white setose; pro tibia laterally arched; mes tibia laterally arched; met tibia laterally arched, met tibia cylindrical with distinct ventral keel terminating into distinct spur, macroseta at tip of spur, almost reaching tip of 1st tarsomere, postero-laterally sparse long white, erect setose with setae arranged in distinct row; pro + mes tarsomere 1 as long as tarsomere 2, met tarsomere 1 as long as individual tarsomeres 2, 3, or 4; pulvillus reduced, ½ length of well-developed claw; setiform empodium absent.

Wing: length = 7.0-7.9 mm; hyaline throughout, veins light brown, microtrichia absent; cells r1, r4, m3, + cua closed, r5 open; C terminating at junction with R1; Sc long, terminating in C proximal to r-m; R4 terminates in R1; R5 terminates in R1; auxiliary vein (R3) at base of R4 absent; R4 and R5 widest apart medially; r-m distinct, R4+5 and M1 apart, connected by crossvein; M1 straight at r-m (not curving anteriorly), M1 (or M1+M2) terminates in C (not reaching wing margin), rarely C; base of M3+M4 present, M3+M4 not terminating together in C (not reaching wing margin), M4 and CuA split proximally to m-cu (cell m3 narrow proximally); CuP straight, cell cup wide, CuP and wing margin further apart proximally than distally; alula entirely reduced (nearly straight wing margin); halter light brown, apubescent, dorsally asetose, ventrally yellow setose.

Abdomen: light brown to brown, setation comprised of scattered short white setae, T2-4 parallel-sided and not constricted waist-like, T surface entirely smooth; T1-4 light brown with narrow yellowish posterior margins, T5-7 brown with narrow yellowish posterior margins; T1-4 grey pubescent, T5 sparsely grey pubescent medially, T6-7 apubescent; T1 short white setose, T2-6 sparsely very short white setose, T7 short erect white setose; S1 light brown, S2-3 brown with yellowish posterior margins, S4-7 brown; S apubescent; S1-7 sparsely short white setose; bullae on T2 transversely elongate, yellow, surface entirely smooth, T2 surface anterior to bullae smooth.

♀ abdomen and genitalia: densely arranged anteriorly directed setae present on T7-8 and S7-8; T8 anterior apodeme present, broad and rectangular, auxiliary spiracle present; T9 formed by wide, rectangular sclerite with median protuberance; T9+10 entirely fused (sclerites indistinguishable), T10 divided into 2 heavily sclerotized acanthophorite plates; 6 acanthophorite spines per plate; 2 spermathecae, all equally large, not differentiated from spermathecal ducts, weakly sclerotized; individual spermathecal duct short; S9 (furca) formed by 1 sclerite, inverted U-shaped (joined anteriorly, separated posteriorly), anterior furcal apodeme present, 2 lateral projections forming divided apodeme, lateral furcal apodeme absent, median furcal bridge absent.

Male. Head: black, facial gibbosity brown, in general grey pubescent, white setose, regular, cylindrical setae; width distinctly greater than thorax (at postpronotal lobe), interocular distance on vertex same as at ventral eye margin; vertex between compound eyes ± horizontally straight, medially only slightly below dorsal eye margin, vertex grey pubescent, white setose; ocellar triangle apubescent; facial gibbosity distinct, well-developed and discernible in lateral view, mystax covering entire facial gibbosity, white; parafacial area approximately as wide as ½ width of central facial gibbosity (at same level); frons not elevated, grey pubescent, white setose; occiput grey pubescent, white setose, median occipital sclerite light brown macrosetose; pocl macrosetae absent; postgena sparsely grey pubescent, long, sparsely white setose; clypeus comprised of single sclerite, entirely sclerotized medially, flat to protruding (convex) ventrally, ventrally expanded, anterior to proboscis (almost covering it), laterally connected to face by sclerotized cuticle; proboscis very short, vestigial, knob-like, brown; labellum indiscernible, length indiscernible, sclerotization indiscernible; maxillary palpus cylindrical, light brown, minute.

Antenna: light brown to brown; scape white setose dorsally, asetose ventrally; pedicel white setose dorsally and ventrally; postpedicel cylindrical in proximal ⅓, symmetrically bulbous in distal 2/3, ≥ 3.0 times as long as combined length of scape and pedicel, asetose; apical seta-like sensory element situated apically in cavity on postpedicel.

Thorax: black, predominantly grey pubescent; scutum uniformly black, surface microrugose (slightly rugose ‘imitating’ pubescence), predominantly grey pubescent, broad sublateral stripes (interrupted by transverse suture) and narrow paramedian stripes merging postsuturally and not reaching posterior margin apubescent, scutal setation comprised of long white setae in pubescent areas; dc setae pre- and postsuturally white, acr setae absent, lateral scutal setae white, npl setae 0, spal setae 0, pal setae 0; proepisternum apubescent medially, grey pubescent laterally, long yellowish macrosetose; proepimeron grey pubescent, asetose; antepronotum antero-medially smooth (without any indentation); lateral postpronotum long white setose; postpronotal lobe light brown, grey pubescent, short yellowish setose; scutellum grey pubescent, discal scutellar setae absent, apical scutellar setae absent; mesopostnotum grey pubescent, asetose; anatergite grey pubescent, asetose; katatergite grey pubescent, long white setose, elevated and smoothly convex; anepisternum grey pubescent, anteriorly asetose, posteriorly asetose, otherwise asetose; katepisternum grey pubescent, asetose; anepimeron grey pubescent, single long yellowish seta dorso-medially; katepimeron grey pubescent, asetose; meron grey pubescent, asetose; metakatepisternum large; metanepisternum grey pubescent, asetose; metepimeron brown (same color as T1), grey pubescent, long white setose, ± flat, infra-halter sclerite absent.

Legs: brown, setation comprised of white setae, yellow macrosetae; pro coxa sparsely grey pubescent, short white macrosetose; mes coxa sparsely grey pubescent, short white setose; met coxa laterally unsclerotized (membrane between coxa and metakatepisternum clearly visible), sparsely grey pubescent, short white setose; met trochanter setose medially; pro + mes femur brown, met femur brown, distinctly clubbed for nearly entire length, macrosetose with thickened spine-like macrosetae on protuberances in 1 antero-ventral and 1 postero-ventral rows, 2-3 macrosetae distally in anterior row, postero-ventrally sparse, long white erect setose; pro tibia laterally arched; mes tibia laterally arched; met tibia laterally arched, met tibia cylindrical with distinct ventral keel terminating into distinct spur, macroseta at tip of spur, almost reaching tip of 1st tarsomere, postero-laterally sparse long white, erect setose with setae arranged in distinct row; pro + mes tarsomere 1 as long as tarsomere 2, met tarsomere 1 as long as individual tarsomeres 2, 3, or 4; pulvillus well-developed, as long as well-developed claw, and as wide as base of claw; setiform empodium absent.

Wing: length = 5.0-7.0 mm; hyaline throughout, veins light brown, microtrichia absent; cells r1, r4, m3, + cua closed, r5 open; C terminating at junction with R1; Sc long, terminating in C proximal to r-m; R4 terminates in R1; R5 terminates in R1; auxiliary vein (R3) at base of R4 absent; R4 and R5 widest apart medially; r-m distinct, R4+5 and M1 apart, connected by crossvein; M1 straight at r-m (not curving anteriorly), M1 (or M1+M2) terminates in C (not reaching wing margin), rarely C; base of M3+M4 present, M3+M4 not terminating together in C (not reaching wing margin), M4 and CuA split proximally to m-cu (cell m3 narrow proximally); CuP straight, cell cup wide, CuP and wing margin further apart proximally than distally; alula entirely reduced (nearly straight wing margin); halter light brown, apubescent, dorsally asetose, ventrally yellow setose.

Abdomen: brown, setation comprised of scattered short white setae, T2-4 parallel-sided and not constricted waist-like, T surface entirely smooth; T1-7 brown with yellow posterior margins, dark brown lateral margins; T entirely grey pubescent; T1-7 short white setose; S1 brown, S2-6 brown with yellow posterior margins, S7 brown; S apubescent; S1-7 short white setose; bullae on T2 oval, small, yellow, surface entirely smooth, T2 surface anterior to bullae smooth.

♂ abdomen and terminalia: T1-7 well-developed, entirely sclerotized, T8 postero-medially weakly sclerotized, with anterior transverse sclerotized bridge connecting lateral sclerites; T7-8 anteriorly with 2 lateral apodemes; T8 auxiliary spiracle present; S6 regular, without any special setation postero-medially; S8 simple plate, entire (undivided) ventro-medially, not fused to T8 dorso-laterally; epandrium formed by 2 sclerites, separated medially and fused anteriorly, distally in dorsal view blunt, evenly rounded; subepandrial sclerite without lateral or median protuberances; hypandrium concave, cup-shaped, entirely sclerotized ventrally, entirely fused with gonocoxite, forming a gonocoxite-hypandrial complex, supra-hypandrial sclerite absent; gonocoxite simple, long, slightly curved dorsally, without median or lateral protuberance, gonocoxal apodeme absent; 2 functional phallic prongs, short and wide, medio-distally connected, parallel or diverging laterally, distally straight or only diverging slightly laterally; phallic epimere absent; lateral ejaculatory process absent; ejaculatory apodeme formed by single dorso-ventrally oriented plate; ventro-median margin of parameral sheath heavily sclerotized (appearing entirely closed); parameral sheath long, sperm sac entirely covered; sperm sac appearing ± heavily sclerotized.

Type locality.

Namibia: Erongo: Gobabeb, 5 km N (23°30'54"S, 015°02'35"E, -23.515, 15.04306).

Material examined.

Namibia: Erongo: 1♂ Gobabeb , 5 km N, 23°30'54"S, 015°02'35"E, 1979-05-08, Wharton, R. ( NMSA-DIP-92011 , Holotype, NMSA) ; 1♂ Gobabeb , 5 km N, 23°30'54"S, 015°02'35"E, 1979-05-08, Wharton, R. ( NMSA-DIP-52603 , Paratype, NMSA) ; 1♂ Gobabeb , plains, 23°33'20"S, 015°02'40"E, 1979-05-12, Wharton, R. ( AAM-007357 , Paratype, NMNW) ; 1♂ Gobabeb , plains, 23°33'20"S, 015°02'40"E, 1979-05-12, Wharton, R. ( NMSA-DIP-52577 , Paratype, NMSA) ; 1♀ Gobabeb , plains, 23°33'20"S, 015°02'40"E, 1979-05-12, Wharton, R. ( NMSA-DIP-92012 , Paratype, NMSA) ; 1♀ Gobabeb , plains, 23°33'20"S, 015°02'40"E, 1979-05-14, Wharton, R. ( NMSA-DIP-52578 , Paratype, NMSA) ; 1♂ Gobabeb , plains, 23°33'20"S, 015°02'40"E, 1979-05-11, Wharton, R. ( NMSA-DIP-52599 , Paratype, NMSA) .

Distribution, biodiversity hotspots, phenology, and biology.

Known only from two nearby localities in the central Namib Desert in Namibia (Fig. 57 ). A rarely collected species known only from seven specimens from three collecting events in 1979 (Table 1 ). The species is not known to occur in any currently recognized biodiversity hotspot. Adult flies are active in May in mid-autumn (Table 2 ), which is after a usually moister period and high temperatures in this part of the Namib Desert (data for Gobabeb, Namibia, see www.worldweatheronline.com/gobabeb-weather-averages/erongo/na.aspx). Wharton (1982, p. 149) stated that he observed an attempted mating by two males with the same female at 13 h 00 on 1979-05-12, which was unsuccessful due to interference (female specimen NMSA-DIP-92012 and male specimens AAM-007357 and NMSA-DIP-52577 (Wharton number 332)). Wharton (1982) furthermore highlighted the fact that E. whartoni sp. nov. might only emerge as an imago following the onset of strong autumn winds.

Remarks.

Wharton (1982) in his seminal year-long study of Mydidae at Gobabeb discovered this species for the first time (identified as Eremohaplomydas sp.) and remains the only collector.

Figures

Figure 57. Map of southern Africa with elevational relief and biodiversity hotspots (sensu Conservation International in grey) and distribution of Eremohaplomydas stomachoris sp. nov., Eremohaplomydas whartoni sp. nov. (both localities only 5 km apart), and Haplomydas crassipes (SimpleMappr https: // www. simplemappr. net / map / 14090). Distribution and occurrence data available in Google Earth KML file https: // www. simplemappr. net / map / 14090. kml and also through GBIF (data-set https: // www. gbif. org / dataset / 993875 DD- 5915 - 4107 - 8707 - 835 D 5 A 8 D 1022, DOI https: // doi. org / 10.15468 / awpjz 9).

Figures 19 - 24. Eremohaplomydas whartoni sp. nov.: 19 ♂ holotype (NMSA-DIP- 92011, Zenodo https: // doi. org / 10.5281 / zenodo. 6083939), dorsal (https: // doi. org / 10.5281 / zenodo. 6084009) 20 same, lateral (https: // doi. org / 10.5281 / zenodo. 6084011) 21 same, head anterior (https: // doi. org / 10.5281 / zenodo. 6084013) 22 ♀ paratype (NMSA-DIP- 92012, https: // doi. org / 10.5281 / zenodo. 6083936), head anterior (https: // doi. org / 10.5281 / zenodo. 6084007) 23 same, dorsal (https: // doi. org / 10.5281 / zenodo. 6084003) 24 same, lateral (https: // doi. org / 10.5281 / zenodo. 6084005). Scale bars: 5 mm.

Figures 25 - 30. Eremohaplomydas whartoni sp. nov. ♀ and ♂ terminalia: 25 ♀ paratype (NMSA-DIP- 52578, Zenodo https: // doi. org / 10.5281 / zenodo. 6083932), dorsal (https: // doi. org / 10.5281 / zenodo. 6083991) 26 same, ventral (https: // doi. org / 10.5281 / zenodo. 6083995) 27 same, lateral (https: // doi. org / 10.5281 / zenodo. 6083993) 28 ♂ paratype (NMSA-DIP- 52577, https: // doi. org / 10.5281 / zenodo. 6083934), lateral (https: // doi. org / 10.5281 / zenodo. 6083999) 29 same, dorsal (https: // doi. org / 10.5281 / zenodo. 6083997) 30 same, ventral (https: // doi. org / 10.5281 / zenodo. 6084001). Magnification 25 - 27 = 50 x, 28 - 30 = 75 x.

Figures 31 - 34. Heads of Eremohaplomydas species in ventro-lateral view: 31 E. desertorum ♂ paratype (MZLU- 2143: 2, 60 x magnification, Zenodo https: // doi. org / 10.5281 / zenodo. 6083967) 32 E. gobabebensis sp. nov. ♂ holotype (USNMENT 01518012, 75 x, https: // doi. org / 10.5281 / zenodo. 6083981) 33 E. stomachoris sp. nov. ♀ holotype (AAM- 003035, 75 x, https: // doi. org / 10.5281 / zenodo. 6083989) 34 E. whartoni sp. nov. ♂ holotype (NMSA-DIP- 92011, 75 x, https: // doi. org / 10.5281 / zenodo. 6084015).