Rinhatiana arctifestuca, Irwin & Winterton, 2024

Irwin, Michael E. & Winterton, Shaun L., 2024, New genera of stiletto flies endemic to Madagascar (Therevidae: Therevinae), European Journal of Taxonomy 932 (1), pp. 1-33 : 4-7

Rinhatiana arctifestuca gen. et sp. nov.

urn:lsid:zoobank.org:act:4247C900-00F3-435E-B883-572A5925FDF5

Figs 1–2 , 9A–B , 15A , 16A–B, L , 18

Diagnosis

Frons predominantly matte black and silver pubescent, tan pubescence dorsally ( Fig. 9A–B ); male eyes nearly contiguous; single row of postocular macrosetae in both sexes; dorsocentral macrosetae absent; one supra alar macroseta ( Figs 1–2 ); male abdomen yellow with silver pubescence laterally, suffused with black distally and posterolaterally on some distal tergites ( Fig. 1 ).

Differential diagnosis

Rinhatiana arctifestuca gen. et sp. nov. differs from all other members of the genus by a distinctive pattern of frontal pubescence ( Fig. 9A–B ), yellow abdomen with black distally and broad gonostylus in the male genitalia. Amongst other characters, it differs from R. cracentis gen. et sp. nov. by the bright silver pubescence around the base of the antennae (silver-tan in R. cracentis ), from R. distincta by the presence of a single pair of supra alar macrosetae (two pairs in R. distincta ), and from R. latifestuca gen. et sp. nov. by the presence of tan pubescence dorsally on the frons (lacking in R. latifestuca ).

Etymology

The specific epithet is derived from the Latin ʻ arcto ʼ (ʻnarrowʼ) and ʻ festuca ʼ (ʻstalkʼ). Gender is female.

Material examined

Holotype MADAGASCAR – Mahajanga Province (Sofia Region) • ♂; 5 km W of Anjiamangirana ; 15.1571° S, 47.7341° E; 97 m a.s.l.; 4–11 Jul. 2013; M.E. Irwin and R. Harin’Hala leg.; Malaise in Analagnambe gallery forest; CASC.

Paratypes MADAGASCAR – Mahajanga Province (Sofia Region) • 34 ♂♂, 10 ♀♀; same collection data as for holotype; various dates: 16 Aug.–6 Sep. 2012, 13–20 Sep. 2012, 28 Sep.–4 Oct. 2012, 27 Jun.–11 Jul. 2013, 18–25 Jul. 2013, 22–29 Aug. 2013, 12–19 Dec. 2013, 29 Sep.–5 Dec. 2013, 18–25 Sep. 2014; CASC . – Antsiranana Province, Sava Region • 6 ♀♀; Binara, 9 km SW of Daraina ; 13.2489° S, 49.6174° E; 182 m a.s.l.; 3–16 Jul. 2011; M.E. Irwin and R. Harin’Hala leg.; Malaise in Antsahabelela degraded rainforest; CASC .

Other material

MADAGASCAR – Mahajanga Province (Sofia Region) • 31 ♂♂, 46 ♀♀; 5 km W of Anjiamangirana ; 15.1571° S, 47.7341° E; 97 m a.s.l.; various dates: 26 Jul.–16 Aug. 2012, 6–28 Sep. 2012, 6–13 Jun. 2013, 20–27 Jun. 2013, 11–18 Jul. 2013, 25 Jul.–1 Aug. 2013, 8–15 Aug. 2013, 29 Aug.–5 Sep. 2013, 5–12 Dec. 2013, 7 Aug.–18 Sep. 2014, 25 Sep.–2 Oct. 2014; M.E. Irwin and R. Harin’Hala leg.; Malaise in Analagnambe gallery forest; CSCA . – Antsiranana Province (Sava Region) • 17 ♂♂, 35 ♀♀; Binara, 9 km SW of Daraina ; 13.2489° S, 49.6174° E; 182 m a.s.l.; various dates: 3–10 Jul. 2011, 20–27 Jul. 2011, 12 Aug.–23 Sep. 2011; M.E. Irwin and R. Harin’Hala leg.; Malaise in Antsahabelela degraded rainforest; CASC .

Description

BODY LENGTH. 5.0–6.0 mm (male), 6.0– 7.5 mm (female).

HEAD. Frontal pubescence silver ventrally, gray-tan dorsally, separated by matte black band medially, extending dorsally and ventrally ( Fig. 9A–B ); male frons width at narrowest point narrower than anterior ocellus but eyes not contiguous; frontal vestiture absent; ocellar tubercle gray pubescent, setae absent; black postocular macrosetae in single row immediately laterad of ocellar tubercle in both sexes; occiput pubescence tan-brown; genal setae pale; antennal scape short, cylindrical, dark yellow, sparsely covered with short, dark macrosetae; flagellum shape conical, tapered distally, orange-yellow, terminus dark.

THORAX. Scutum tan-brown to yellow with gray areas laterally and medially, scattered short dark setae; scutellum dark yellow (female) or brownish orange, dark brown anteromedially (male); pleuron with dense silver-gray pubescence; katatergite setae uniform pale; scutal and scutellar macrosetae black, relatively elongate; coxae yellow, overlain with silver-gray pubescence, minor setae white; black macrosetae few in number; femora yellow with sparse, short filiform setae admixed with sparse, black, adpressed scale-like setae distally (at least on hind femur); femoral macrosetae black, hind femur with subapical series of short posteroventral macrosetae, subapical anteroventral setae present; tibiae yellow, dark gray-brown apically; tarsi basitarsi yellow, dark distally, remaining tarsal segments brown; wing faint infuscate, darker anteriorly; venation dark yellow basally along major veins, darker distally; haltere dark yellow; scutal chaetotaxy: notopleural, 3, supra alar, 1; post alar, 1; dorsocentral, 0; scutellar, 2.

ABDOMEN. Male abdomen dark yellow, darker brown posterolaterally on most tergites, silver velutum present on tergites 2–7; scattered dark setae, denser posteriorly and on terminalia, filiform setae admixed with adpressed setae; female abdomen similar to male; terminalia brown (male) or dark yellow (female).

MALE GENITALIA. Epandrium quadrangular, strongly arched around midline, posterolateral thickening relatively broad medially; gonocoxites with elongate macrosetae laterally on outer gonocoxal process, outer gonocoxal process well-developed, narrowly subtriangular; ventral lobe elongate, broadly rounded; gonostylus with broad lateral flange along most of length; distiphallus relatively broad; sternite 8 sub-quadrangular, few setae posterolaterally.

Remarks

Rinhatiana arctifestuca gen. et sp. nov. is very similar in appearance to R. latifestuca gen. et sp. nov., especially in the frontal pubescence pattern. Unlike other species in this genus, R. arctifestuca appears restricted to northern Madagascar where it has been collected in dry deciduous forest habitats.

Figures

Fig. 1. Rinhatiana arctifestuca gen. et sp. nov., ♂, paratype (CASC). A. Lateral view. B. Oblique view.

Fig. 2. Rinhatiana arctifestuca gen. et sp. nov., ♀ (CASC). A. Lateral view. B. Oblique view.

Fig. 9. Rinhatiana spp., heads, anterior view. A. Rinhatiana arctifestuca gen. et sp. nov., ♂ (CSCA). B. Same, ♀ (CSCA). C. Rinhatiana cracentis gen. et sp. nov., ♂ (CSCA). D. Same, ♀ (CSCA). E. Rinhatiana distincta (Lyneborg, 1976) comb. nov., ♂ (CSCA). F. Same, ♀ (CSCA). G. Rinhatiana latifestuca gen. et sp. nov., ♂ (CSCA). H. Same, ♀ (CSCA).

Fig. 15. Rinhatiana gen. nov. and Tianarinha gen nov., epandrium. A. Rinhatiana arctifestuca gen. et sp. nov. (CSCA). B. Rinhatiana cracentis gen. et sp. nov. (CSCA). C. Rinhatiana latifestuca gen. et sp. nov. (CSCA). D. Rinhatiana distincta (Lyneborg, 1976) comb. nov. (CSCA). E. Tianarinha micet gen. et sp. nov., epandrium and tergite 8. (CSCA). F. Tianarinha goodmani gen. et sp. nov. (CSCA). Scale bar = 0.2 mm.

Fig. 16. Rinhatiana gen. nov. andTianarinha gen nov.A–K. Male gonocoxites and phallus with epandrium removed. A. R. arctifestuca gen. et sp. nov. (CSCA), ventral view. B. Same, dorsal view. C. R. cracentis gen. et sp. nov. (CSCA), ventral view. D. Same, dorsal view. E. R. latifestuca gen. et sp. nov. (CSCA), ventral view. F. Same, dorsal view. G. T. goodmani gen. et sp. nov. (CSCA), ventral view. H. Same, dorsal view. I. T. micet gen. et sp. nov. (CSCA), ventral view. J. Same, dorsal view. K. R. distincta (Lyneborg, 1976) comb. nov. (CSCA), ventral view. L–P. Sternite 8. L. R. arctifestuca gen. et sp. nov. (CSCA) (with tergite 8). M. R. cracentis gen. et sp. nov. N. T. goodmani gen. et sp. nov. (CSCA). O. R. latifestuca gen. et sp. nov. (CSCA). P. T. micet gen. et sp. nov. (CSCA). Scale bars = 0.2 mm.

Fig. 18. Distribution of species of Rinhatiana gen. nov. with eco-regions indicated. Inset image of adult ♀ of R. latifestuca gen. et sp. nov. (photograph copyright: Len de Beer).