Dixella fernandezae Chaverri and Borkent, 2007

Chaverri, Luis Guillermo & Borkent, Art, 2007, The Meniscus midges of Costa Rica (Diptera: Dixidae), Zootaxa 1575 (1), pp. 1-34 : 15-17

Dixella fernandezae Chaverri and Borkent n. sp.

( Figures 1E , 6E , 8A , 12A , 18B )

Diagnosis. Male: only species of Dixidae in Central America with a short clypeus ( Fig. 1E ), uniformly dark pleura, R2+3 originating distal to r-m, and with the subapical gonocoxal lobe short and not extending beyond the apex of the gonocoxite ( Fig. 12A ). Female: unknown.

Description. Male. Head ( Fig. 1E ): brown, densely spiculate. Clypeus yellowish, 1.2 wider than long. Antennal scape, pedicel brown, flagellomeres lost. Thorax: scutum not visible. Scutellum brown, mediotergite yellowish. Pleura with pronotum, propleuron brown; posteroapical region of katepisternum, basal anepimeron yellowish; 2 setae on posteroventral margin of posterior anepisternum. Wing ( Fig. 6E ; Table 1): with or without slight darkening over r-m; R2+3 originating distal to r-m; stem of R2+3 0.50 length of R3. Halter: pale, 0.40 length of fore femur. Legs: yellowish; claws as figured, hind claws not visible ( Fig. 8A ). Genitalia ( Fig. 12A ): tergite 9 with anterior, posterior margins nearly straight, with scattered setae. Sternite 9 with posterior margin with broad excavation, with three lateral setae. Gonocoxite wider than long; basal lobe not well defined; apical lobe cylindrical, tusk-like, slightly curved dorsally, tip acute, 0.50 length of gonostylus, with elongate basal seta, elongate midlength seta, two short subapical setae. Gonostylus slightly wider at base, tapering gradually to apex, apex acute, four elongate subapical setae. Parameres dark brown, narrow, directed dorsally, apices divergent. Aedeagus triangular. Tergite 10 light brown, with anterolateral extension posterior margin slightly bilobed, with three short subapical setae.

Female and immatures. Unknown.

Distribution and bionomics. This species is known only from the type locality in Costa Rica at 1540 m ( Fig. 18B ) and has been collected during the dry season (June). The holotype was swept from vegetation in an area of several small streams. The habitat corresponds to Tropical Lower Montane Rainforest.

Taxonomic discussion. The apical lobe of the gonocoxite is similar to that of D. hansoni but the shapes of the parameres and aedeagus are distinctive (see key) ( Figs. 11B , 12A ).

Types. Holotype, male adult on microscope slide, labeled “ HOLOTYPE Dixella fernandezae Chaverri and Borkent ”, “ Costa Rica, Puntarenas, Monteverde, 2 Km E. de Santa Elena, Estación Biológica Monteverde , 1540 m, 12-VI-2000, A. Borkent, CD 5085, LN 255800 447900” ( CNCI).

Derivation of specific epithet. This species is named in recognition of the contribution of Xinia Fernández, a former technician working at INBio, who reared numerous nematocerous Diptera (and especially Culicidae ) and prepared a large collection of microscope slides.

Figures

FIGURE 1. Head capsules of male Dixella, anterior view. (A) D. maculata; (B) D. hernandezi; (C) D. shannoni; (D) D. hansoni; (E) D. fernandezae; (F) D. jironi; (G) D. venezuelensis; (H) D. woodi; (I) D. lobata; (J) D. suzukii.

FIGURE 6. Wings of male Dixella. (A) D. maculata; (B) D. hernandezi; (C) D. shannoni; (D) D. hansoni; (E) D. fernandezae; (F) D. jironi; (G) D. venezuelensis; (H) D. woodi; (I) D. lobata; (J) D. suzukii.

FIGURE 8. Claws of male Dixella. (A) D. fernandezae; (B) D. jironi; (C) D. venezuelensis.

FIGURE 11. Genitalia of male Dixella, dorsal view. (A) D. shannoni; (B) D. hansoni.

FIGURE 12. Genitalia of male Dixella, dorsal view. (A) D. fernandezae; (B) D. jironi.

FIGURE 18. Distributions of Dixella species in Costa Rica: (A) D. maculata—O; D. hernandezi–-#, D. shannoni— ; (B) D. hansoni—O, D. fernandezae—#, D. jironi— .