Rinhatiana distincta Irwin & Winterton 2024, comb. nov.
Creators: name: Irwin, Michael E.
name: Winterton, Shaun L.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Therevidae
Rinhatiana
Rinhatiana distincta

description: Rinhatiana distincta (Lyneborg, 1976) comb. nov.
Figs 5– 6, 9E–F, 15D, 16K, 18
Stenopomyia distincta Lyneborg, 1976: 237.
Stenopomyia distincta – Irwin (2003: 733).
Diagnosis
Frons predominantly matte black and silver pubescent, female with tan pubescence dorsally (Fig. 9E– F); male eyes separated at narrowest point by width slightly wider than anterior ocellus; two rows of postocular macrosetae in both sexes; dorsocentral macrosetae present; two pairs of supra alar macroseta (Figs 5–6); abdomen yellow terminal segments and genitalia black, male with silver pubescence on tergites 4–7; male ventral lobe with acute processes (Fig. 16K).
Differential diagnosis
Rinhatiana distincta differs from all other members of the genus by the relatively wide male frons (Fig. 9E), presence of dorsocentral macrosetae and two pairs of supra alar macrosetae. Amongst other characters, it differs from R. arctifestuca gen. et sp. nov. and R. latifestuca gen. et sp. nov. by two pairs of supra alar macrosetae (one pair in both) and presence of dorsocentral macrosetae (absent in both). It differs from R. cracentis gen. et sp. nov. also in the above characters, as well as the yellow abdomen with black terminal segments (dark brown and dark yellow in R. cracentis).
Material examined
Holotype MADAGASCAR – Tulear Province (Atsimo-Andrefana Region) • ♂; Zombitse Forest [Zombitse-Vohibasia National Park]; [22.886° S, 44.686° E]; 300 m a.s.l.; 22 Mar. 1968; K.M. Guichard and P.D. leg.; NHMUK.
Paratype MADAGASCAR – Tulear Province (Atsimo-Andrefana Region) • ♀; same collection data as for holotype; NHMUK.
Other material
MADAGASCAR – Tulear Province (Atsimo-Andrefana Region) • 1 ♂, 1 ♀; Manombo; 22.8025° S, 43.7651° E; 227 m a.s.l.; 9–14 Apr. 2004; CAS leg.; MT in dry forest; MGF102; CASC.
Redescription
BODY LENGTH. 5.5–7.5 mm (male), 7.0–8.0 mm (female).
HEAD. Frontal pubescence silver ventrally, gray-tan dorsally, separated by broad matte black band; male frons width at narrowest point slightly wider than anterior ocellus, short black setae below ocellar tubercle, more extensive on frons in female; ocellar tubercle gray pubescent with short setae; postocular macrosetae black, in two well-defined rows in both sexes; occiput pubescence gray; genal setae pale; antennal scape shorter than flagellum, cylindrical, dark yellow, sparsely covered with short, dark macrosetae; flagellum conical, tapered distally, style greatly elongate, dark yellow with brown pubescence.
THORAX. Scutum dark yellow, markings with faint pair of dorsocentral stripes along length, scattered dark setae, denser anteriorly; scutellum dark yellow; pleuron yellow with sparse silver pubescence; katatergite setae pale; scutal and scutellar macrosetae black, relatively elongate; coxae yellow, overlain with silver-gray pubescence, minor setae white and sparse, macrosetae black and few in number; femora yellow with short dark setae admixed with longer pale setae and black adpressed scale-like setae; hind femur with 1–2 subapical anteroventral macrosetae, subapical series of short posteroventral macrosetae; tibiae dark yellow, suffused with brown, darker on hind leg; tarsi dark brown; wing hyaline, smoky infuscate apically; venation yellow basally along major veins, darker distally; haltere stem yellow, knob white; scutal chaetotaxy (pairs): notopleural, 3; supra alar, 2; post alar, 1; dorsocentral, 1; scutellar, 2.
ABDOMEN. Male abdomen dark yellow suffused with black on posterior segments, silver velutum present on tergites 4–7, elongate adpressed black setae on segments 1–3, white on segments 4–7; female abdomen dark yellow, segments 7–8 black, intersegmental membrane usually not distinct from tergite; terminalia black in both sexes.
MALE GENITALIA. Epandrium quadrangular, strongly arched along midline, posterolateral corners sharply pointed; gonocoxite rounded, with extensive large black macrosetae, longer posterolaterally; hypandrium separate from gonocoxites, band-like; outer gonocoxal process very short with elongate setae; inner gonocoxal process elongate, pointed with hemispherical dorsal ridge; gonostylus narrow, elongate and much longer than outer gonocoxal process; phallus with dorsal apodeme of parameral sheath triangular and well developed, ejaculatory apodeme narrow, lateral ejaculatory apodeme relatively small, distiphallus narrow, reflexed ventrally; ventral lobe elongate, with multiple acute branches.
Remarks
Rinhatiana distincta was originally described in the genus Stenopomyia by Lyneborg (1976). The presence of setulae on the dorsal surface of wing vein R 1, a character apparently overlooked by Lyneborg, is notable in not being known in the subfamily at the time. Amongst other characters the presence of these setulae clearly places it within this new genus Rinhatiana gen. nov. Even here though, it has a rather isolated position, displaying several exceptional characters in the genus, including the relatively wide male frons, presence of dorsocentral macrosetae, two pairs of supra alar macrosetae, and two rows of postocular macrosetae in both sexes. This species has only been rarely collected, with all specimens known from southern Madagascar in spiny thicket habitat. Also notable is that the description and figures of the male phallus by Lyneborg (1976: figs 135, 136) appear to be incomplete and the structure was likely damaged during dissection. The dorsal apodeme of the phallus is larger and subtriangular in shape in an undamaged specimen, and typical of the genus.
description: Published as part of Irwin, Michael E. & Winterton, Shaun L., 2024, New genera of stiletto flies endemic to Madagascar (Therevidae: Therevinae), pp. 1-33 in European Journal of Taxonomy 932 (1) on pages 10-13, DOI: 10.5852/ejt.2024.932.2507, http://zenodo.org/record/11001504