Austrothaumalea fredericki Pivar, 2020

Pivar, Robert J., Sinclair, Bradley J. & Moulton, John K., 2020, Revision of the South American species of Austrothaumalea Tonnoir (Diptera Thaumaleidae), Zootaxa 4853 (4), pp. 509-526 : 515-518

Austrothaumalea fredericki Pivar sp. nov.

( Figs 3D , 4C , 5C , 8 , 9B )

Type material. Holotype: ♂, glued to point with abdomen in glycerine microvial pinned beneath, labelled: “ CHILE: Region X ( Los / Lagos ) East side Lago / Llanquihue / small falls on road (nr PN/ VPR) 41°08.47′S / 72°35.28′W ~ 100m / 2.xii.2008 GW Courtney/ (CH08-30)”; “ HOLOTYPE / Austrothaumalea / fredericki / Pivar [red label]” ( CNC).

Recognition. This species is recognized by its cruciate parameres. The lateral, cross-like projections on the paramere are located at mid-length, concealed by the gonocoxal plate (in ventral view) and are much longer than those of A. chilensis .

Description. Male. n = 1. Length 2.8 mm. Colouration ( Fig. 3D ). Head dull, dark brown; pronotum, postpronotum, postpronotal lobe and lateral margins of prescutum yellowish brown; prescutum and mesoscutum shiny, primarily yellow, with pleura yellowish brown; two lateral brown spots above scutoscutellar suture; scutellum and mediotergite shiny, yellow; paratergite yellowish brown; katepisternum mainly yellow, remaining pteropleuron yellowish brown; halter brown; legs pale brown, tarsi darker; abdomen brown; terminalia light brown.

Head. Eyes above antennae broadly joined, barely exposing frons above antennae. Flagellomeres 1–3 expanded, subquadrate; 1 as long as 2 and 3 combined; flagellomeres 4–10 thin, cylindrical, becoming progressively more elongate. Vertex clothed in golden setae of uniform length, with sparse long, black orbital setae.

Thorax. Pronotal setae longer than scutal setae. Scutum clothed dorsally in short setulae; notopleural, supra-alar and postsutural setae long, black. Pteropleuron bare. Fore- and mid legs with tarsomere 4 bilobed; hind tarsi broken, not observed.

Wing. Wing length: 2.9 mm. Lightly infuscate throughout, slightly darker where R 4+5 meets apex; apex rounded; C and posterior wing margin with fringe of microtrichia; Sc incomplete; R 1 and R 1 (+R 2+3) without three weakenings or depigmented gaps; R 1 (+R 2+3) with uniseriate row of microtrichia along entire length, remaining veins bare; R flexed into cell br; R 2+3 crossvein very weak, situated slightly before midpoint of R 1 (+R 2+3); bend in R 4+5 gentle; R 4+5 and M 1 running parallel toward margin; M 1 and M 2 straight; M 4 slightly sinuous; CuA with basal spur shorter than crossvein m-cu.

Abdomen. Abdominal sternite 1 narrow, spectacle-shaped; sternite 2 with slender median sclerite and weakly sclerotized posterior trapezoid, few setae on posterior margin; sternites 3–7 rectangular, weakly sclerotized, setae restricted to posterior third; anterior margin of sternites 5–7 thin, well-sclerotized, sternite 7 arched slightly into preceding segment; sternite 8 triangular, bare, anterior margin well sclerotized, arched strongly into preceding sternite.

Terminalia ( Figs 4C , 5C ). Epandrium trapezoidal from ventral aspect; apical third slightly tapered; posterior margin broad, irregular; lacking pointed posterolateral processes. Hypandrium broad in ventral view, equal to basal width of gonostylus; anterior margin not concave. Gonocoxite broadest at basal third, tapered toward apex, inner margin smooth. Gonostylus about two-thirds length of gonocoxite, distal half strongly curved; broadest basally, gradually tapered to slightly pointed apex. Parameres distally fused, slightly more than half-length of epandrium, cruciform at mid-length, projected ventrally. Gonocoxal plate U-shaped, short, about one-third length of gonocoxite, well sclerotized; lateral arms divergent posteriorly into projections, distal inner margins weakly toothed; membrane extended to middle of paramere, with medial invagination; basally not fused to hypandrium. Cercus weakly sclerotized, situated along midline of epandrium.

Female. Unknown.

Immature Stages. Unknown.

Additional Material Examined. Known only from the holotype.

Distribution. Known only from the type locality in the Southern Andes ( Figs 8 , 9B ).

Etymology. Austrothaumalea fredericki is named in honour of British dipterist Frederick W. Edwards, who was a primary author of the Natural History Museum’s (London) series of books entitled “ Diptera of Patagonia and South Chile ”. Specifically, Edwards was heavily involved in writing the lower Diptera chapters and laid the groundwork for future studies of many families, including Thaumaleidae .

Figures

FIGURE 3. Adult habitus photographs of Austrothaumalea, lateral view. A, A. apicalis (♂); B, A. spatulata (♂); C, A. chilensis (♂); D, A. fredericki sp. nov. (♂); E, A. setipennis stat. rev. (♀). R2+3, second + third radial vein. Scale bars = 1.0 mm.

FIGURE 4. Ventral views of male Austrothaumalea terminalia. A, A. apicalis; B, A. chilensis; C, A. fredericki sp.nov.; D, A. setipennis stat. rev.; E, A. spatulata. Abbreviations: c, cercus; gcx, gonocoxite; gcxP, gonocoxal plate; gst, gonostylus; hypd, hypandrium; pm, paramere.Arrow denotes apical epandrial projection. Scale bars = 0.1 mm.

FIGURE 5. Lateral views of male Austrothaumalea terminalia. A, A. apicalis; B, A. chilensis; C, A. fredericki sp. nov.; D, A. setipennis stat. rev.; E, A. spatulata. Abbreviations: c, cercus; epand, epandrium; gcx, gonocoxite; gcxP, gonocoxal plate; gst, gonostylus; hypd, hypandrium; pm, paramere. Arrow denotes apical epandrial projection. Scale bars = 0.1 mm.

FIGURE 8. Known distribution of South American Austrothaumalea.

FIGURE 9. Examples of Austrothaumalea habitats in Chile. A, rock face seep where A. chilensis and A. setipennis stat. rev. were collected (38°13′20.3″S 71°44′41.1″W); B, collection site of A. fredericki sp.nov. (41°08.47′S 72°35.28′W); C, collection site of A. spatulata (34°59′48.8″S 70°48′37.0″W); D, northernmost collection site of A. spatulata in the Chilean Matorral, inset showing small trickle of water where specimen was collected (34°46′29.2″S 70°40′03.9″W).