Rinhatiana, 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 : 3-4

Rinhatiana gen nov.

urn:lsid:zoobank.org:act:C41C01D5-81EE-46F3-B354-1161454B8A81

Type species

Rinhatiana latifestuca gen. et sp. nov.

Diagnosis

Male and female with single row of postocular macrosetae (rarely more); prosternal setae absent medially; two pairs of scutellar macrosetae; setae absent on metanepisternum and posterior surface of mid coxa; wing vein R 1 with setulae along dorsal surface; wing cell m 3 open.

Differential diagnosis

Rinhatiana gen. nov. belongs to the subfamily Therevinae (characterized by the presence of adpressed, scale-like setae on the femora), but has setulae along wing vein R 1, a character shared with Tianarinha gen. nov. and the New World therevine genus Protothereva Malloch, 1932 . It can be separated from Tianarinha by the absence of prosternal setae and two pairs of scutellar setae (in Tianarinha prosternal setae are present medially and there is only one pair of scutellar setae). In addition, it is separated from Schoutedenomyia by the presence of regular sized macrosetae on the foretibia (relatively small in Schoutedenomyia ). It is distinguished from Stenopomyia and Stenosathe by the wavy R 4 vein in the wing (straight or gradually curved in Stenopomyia and Stenosathe ).

Etymology

ʻ Rinhatiana ʼ is a combination of the nicknames of two key personnel in Madagascar who contributed significantly to the project on the Diptera of Madagascar. We have the honor of naming this genus after Rasolondalao Harin’Hala Hasinjaka (also known as Rin’ha) and Razafindratsita Vololontiana (also known as Tiana). Rin’ha managed and coordinated the Malaise trapping and sample sorting for the project throughout Madagascar, while Tiana managed the administrative aspects of the project within the Madagascar Institut pour la Conservation des Ecosystemes Tropicaux (MICET). Gender is female.

Description

Relatively small individuals with sparse vestiture.

HEAD. Higher than long; frons flat, pubescent silver-tan dorsally, silver ventrally, matte black band medially; frons width strongly sexually dimorphic, male frons width at narrowest point narrower than ocellar tubercle width, nearly contiguous in some species, inner margin of female compound eyes subparallel; parafacial without setae; face flat; postocular ridge of male and female with single row of macrosetae along postocular ridge, rarely two distinct rows; occiput pubescence dull silver to gray or brown; gena rounded; antenna subequal to head length, positioned on lower half of head, directed anteriorly; scape relatively short, cylindrical, less than 3× pedicel length; flagellum tapered cone-shaped, subequal to combined length of scape and pedicel, style apical, elongate; palpus slender, mouthparts short.

THORAX. Central depression of prosternum bare, without setae; cervical sclerite lacking macrosetae; scutum covered with filiform setae, often of variable length; pleuron overlain with silver-tan pubescence; metanepisternum with postspiracular setae absent; metakatepisternum with setae absent; femora relatively short, hind femur and tibia distinctly longer and thicker than fore and mid legs; posterior surfaces of mid- and hind coxae without setae, hind coxal knob present; femoral vestiture includes filiform seta admixed with adpressed, lanceolate and scale-like setae; forefemur and midfemur macrosetae absent, hind femur with 0–3 subapical anteroventral macrosetae, posteroventral macrosetae present as subapical series; tibial macrosetae regular sized; scutal chaetotaxy (pairs of macrosetae): notopleural, 3; supra alar, 1 (rarely 2); post alar, 1; dorsocentral, 0–1; scutellar, 2; wing smoky (light infuscate), vein R 1 with setulae present on dorsal surface, R 4 slightly wavy, cell m 3 open, veins M 3 and M 4 separate to margin, wing membrane uniformly covered with microtrichia.

ABDOMEN. Relatively slender, slightly narrowed along length.

TERMINALIA. Epandrium slightly arched, posterolateral corners thickened and pointed; gonocoxites separate medially with posteromedial margins proximal; inner gonocoxal process (igp) present, not articulated; outer gonocoxal processes well-developed; ventral lobe large, elongate and narrow apically; phallus with dorsal apodeme of parameral sheath triangular, separate from gonocoxites laterally; ventral apodeme single lobe, narrow, single sub-triangular lobe; distiphallus narrow, short; female tergite 8 elongate with anteromedial process; sternite 8 posterior margin emarginate posteromedially; female acanthophorite setae as two sets (A1 & A2), A1 setae usually enlarged; spermathecal sac as single lobe with spermathecal ducts originating on main spermathecal sac duct; two spermathecae.

Remarks

Rinhatiana gen. nov. is a distinctive genus of diminutive flies likely the sister genus to Tianarinha gen. nov. The presence of setulae along the dorsal surface of wing vein R 1 is known in all Phycusinae (except for Schlingeria Irwin, 1977 ) and in only one genus of Xestomyzinae ( Henicomyia Coquillett, 1898 ). They are absent in all known Agapophytinae , while in Therevinae setulate along R 1 is only found in the South American genus Protothereva and some species of the Australian genus Anabarhynchus Macquart, 1848 . Protothereva is placed in the predominantly New World Cerocatus genus group, likely close to Brachylinga Irwin & Lyneborg, 1981 , while Rinhatiana and Tianarinha are placed in the largely Old World Thereva genus group, closely related to Stenopomyia , Stenosathe , Megapalla Lyneborg, 2001 and Schoutedenomyia . Webb & Metz (2003) mentioned that some undescribed species of Stenopomyia had R 1 setulae. Those species are described here in the genera Rinhatiana and Tianarinha . In addition, one previously described species, Stenopomyia distincta Lyneborg, 1976 , also has R 1 setulae and is placed in Rinhatiana .