Mythicomyia tawa, Sánchez & Evenhuis, 2024

Sánchez, Pável & Evenhuis, Neal, 2024, New Mythicomyia Coquillett, 1893 (Diptera: Mythicomyiidae: Mythicomyiinae) from Peru, Zootaxa 5541 (4), pp. 513-538 : 526-530

Mythicomyia tawa sp. nov.

( Figs 55–71 )

Diagnosis. Male.Proboscis longer than height of eye; middle tibia straight; pseudo-surstylus strongly curved inwards, rodlike ( Figs 61–64 ); anterior lobe of gonocoxa medially united forming a small keel ( Figs 65–66 ). Female. Frons whitish yellow, except on upper third, dark brown along eye margin and a faint brown stripe at middle ( Fig. 68 ); spermathecal reservoir extending to abdominal segment III, knob-like and with glandular trichome ( Figs 70–71 ).

Description of the male holotype. Length: body, 3 mm; wing, 2.2 mm.

Head ( Fig. 56 ). Predominantly black, yellow pruinose; eyes contiguous for 10 facets, separated at vertex by about the width of ocellar triangle; anterior ocellus little larger than posterior ones, ocelli yellowish; frons yellowish; face yellowish on the upper half, black bellow; antenna dark brown; scape minute, wider than long; pedicel as long as wide; first flagellomere linear-lanceolate, about 3 times as long as pedicel; second flagellomere lanceolate, about half the length of first one, with subbasal stylus; proboscis dark brown, long, length beyond oral margin about 2.5 times the eye height; occiput and ocellar triangle white setose. Thorax ( Figs 55, 57 ). Predominantly shining black, except yellowish on postpronotal lobe, postalar callus, narrow margin along notopleural and supraalar regions, narrow margins of pleural sclerites and narrow base of scutellum; mesonotum humped, as high as half its length, cinereous pruinose and white setose; pleura yellow pruinose, white setose on anterior margin of anepisternum; scutellum white setose. Legs ( Fig. 55 ). Dark brown to black, except on distal third of femora, ventrally, and first tarsomeres of fore and mid legs, yellowish; middle tibia straight; pulvilli as long as claws. Wing ( Fig. 58 ). Hyaline, microtrichose; veins brownish yellow; costal vein ending in R 4+5; vein Sc incomplete, ending later than of Rs origin; Rs evanescent at connection with R 1; R 2+3 arising approximately ¾ distance from origin of Rs to r-m crossvein, this latter placed at about basal ⅕ of dm cell (first portion of M 1+2, before r-m, shorter than first portion of M 4); vein separating cells br and bm barely evident; cell dm six-sided, about four times as long as wide; m-m cross vein as long as r-m and about ⅕ the length of dm-m; R 4+5 curved downward, ending after M 1; vein M 1 curved downward, slightly sinuous; CuP evanescent; anal lobe developed; haltere and knob white. Abdomen ( Fig. 59 ). Predominantly black, except on posterior margins of abdominal segments, yellowish; white setose. Terminalia ( Figs 60–66 ). Yellowish; epandrium elongate, somewhat rectangular-shaped in lateral view, somewhat circular with scattered setae dorsally in posterior view; pseudo-surstylus narrow and acute at apex, strongly curved inwards, almost meeting the opposite one ( Figs 61–64 ); cercus somewhat triangular, with scattered setae on upper ⅔ in posterior view ( Figs 63–64 ); ejaculatory apodeme thickened, wide and rounded in lateral view ( Figs 61–62 ), long and thin on distal ¾ in posterior view ( Figs 65–66 ); lateral ejaculatory process translucent on basal third, upward-directed in lateral view, sideways-directed and about ¾ the length of ejaculatory apodeme in dorsal view; phallus drop-shaped, distiphallus simple with single apical opening, about a third the length of basiphallus; parameral sheath large, wider than long, with two tips sideways directed and one tip united posteromedially; anterior arms of parameral sheath elongate, thickened, somewhat spatula-shaped with round apex, only extending to half the level of ejaculatory apodeme and convergent in dorsal view ( Figs 65–67 ); gonocoxa subdivided, with an anterior lobe medially united forming an small keel and a posterior lobe tooth-shaped in dorsal view ( Fig. 66 ); gonostylus elongate, with acute apex and upward directed ( Fig. 66 ).

Female ( Figs 67–71 ). Differs from the male description by the following: Head ( Fig. 68 ). Eyes dichoptic, separated at vertex by about 1.5 times the width of ocellar triangle; ocelli only slightly larger than posterior ones; frons whitish yellow, except for a faint black stripe at middle on second third and black suffusion along eye margin on upper third. Thorax ( Fig. 69 ). Black and yellow; mesonotum little humped, black dorsally, notopleural and supraalar regions broadly yellow (shallowly emarginate above notopleural suture); pleura yellow on upper margins of anepisternum, anepimeron, katepisternum and meron; scutellum yellowish with black suffusion medially. Legs ( Fig. 67 ). Coxae and femora yellow with mottled brown suffusion; tibiae and first tarsomeres brownish yellow to dark brown. Abdomen ( Fig. 69 ). More extensively yellow, especially ventrally. Terminalia ( Figs 70–71 ). Genital fork U-shaped, anterior margin gently arched with lower margin acute, posterior margin bifurcate, inner arms as long as outer ones; sperm pump cylindrical with a conspicuous disc-shaped valve apically, relatively small, about a third the length of spermathecal reservoir and as long as genital fork; proximal spermathecal duct as wide as distal; distal spermathecal duct about 8 times as long as proximal duct, translucent; three knob-like spermathecal reservoirs, extending to abdominal segment III, basal third of stem translucent, with glandular trichomes.

Type material. HOLOTYPE. Male: PERU: MO [Department of Moquegua]. [Province of] Mariscal Nieto, [District of] San Antonio , 17°12’51.2”S, 71°4’33.2”W, 1233 m, 20.v.2023, J. Farfán . Holotype in MUSM . PARATYPES. Same data as holotype (3 ♀) ; PERU: MO. Mariscal Nieto, San Antonio , 17°13’51.9”S, 71°4’26.5”W, 1176 m, 20.v.2023, J. Farfán (3 ♂, 2 ♀) ; PERU: MO. Mariscal Nieto , [district of] Moquegua, 17°13’13.23”S, 70°51’3.93”W, 2187 m, 17.ix.2023, F. Ancco (5♂, 3 ♀) ; PERU: IC [Department of Ica]. [Province of] Nazca, [District of] San Juan de Marcona , 15°06’21.7”S, 74°56’2.21”W, 1000 m, 16-18.xi.2023, T. Neyra (2 ♂, 10 ♀) ; PERU: AR. Caravelí, Cháparra, UM Esperanza , 3150 m, 15°37’23”S, 73°55’15”W, 23-24.ii.2024, Yellow pan trap, N. Zenteno leg (2 ♂) . Paratypes in MUSM (4 ♂, 8 ♀) and BPBM (3 ♂, 7 ♀) .

Variation. A few specimens present the cell dm five sided; in one male one wing is six sided and the other one is five sided.

Etymology. The specific epithet is a masculine noun in apposition, tawa is the Quechua word for “four”.

Distribution ( Fig. 91). Southern Peru; Arequipa (Caravelí), Ica (Nazca) and Moquegua (Mariscal Nieto).

Remarks. As explained above, this species is externally similar to the former one, especially in the case of the female. However, they can be distinguished based on the middle tibia straight in the male of M. tawa sp. nov., while in females, differences in frons, mesonotum and terminalia are useful to separate both species. On the other hand, from other species with middle tibia straight and long proboscis, the most similar species is M. citrina Hall, 1976 , but this latter species usually presents a cell dm five sided, something rare in M. tawa sp. nov. In addition, in males, some useful features to differentiate both species are the first abdominal tergite narrowly yellow in middle and the ejaculatory apodeme squarish paddle-like in M. citrina (vs. first abdominal segment all black and the ejaculatory apodeme somewhat rounded in M. tawa sp. nov.). While, in females, M. citrina has legs predominantly black and the scutellum entirely yellow, never with black (vs. legs predominantly yellow and scutellum black medially in M. tawa sp. nov.). It´s worth noting that, according to Hall (1976), M. citrina shows a great variation in most of its diagnostic characteristics, something that need to be reviewed in order to stablish whether the type material includes more than one species or a single one.

Figures

FIGURES 55–60. Mythicomyia tawa sp. nov. Male holotype. 55. Lateral habitus, 56. Head, dorsal view, 57. Thorax, dorsal view, 58. Wing, 59. Abdomen, dorsal view, 60. Terminalia.

FIGURES 61–66. Mythicomyia tawa sp. nov. Male terminalia (based on paratype). 61–62. Lateral view, 63–64. Posterior view, 65–66. Dorsal view.

FIGURES 67–71. Mythicomyia tawa sp. nov. Female. 67. Lateral view, 68. Head, dorsal view, 69. Thorax and abdomen, dorsal view, 70–71. Terminalia.