Diadocidia hybrida, Jaschhof, Mathias & Jaschhof, Catrin, 2007

Jaschhof, Mathias & Jaschhof, Catrin, 2007, On the genus Diadocidia (Diptera, Sciaroidea, Diadocidiidae) in Costa Rica, Zootaxa 1586, pp. 33-38 : 36

Diadocidia hybrida sp. n.

( Fig. 2 A, C and E)

Description. Male. Body length 2.8–3.1 mm. Head. Antennal flagellum bearing short non-socketed setae intermingled with a few sensory spines; longest setae as long as half flagellomere width. First flagellomere 2.3 to 2.7 times as long as wide; bearing dorsally 1–3 short socketed setae ( Fig. 2 A). Fourth flagellomere 1.5 times as long as wide ( Fig. 2 A). Maxillary palpus 5-segmented; third segment 1.8 times as long as second segment, bearing mesially a few short hyaline sensilla apart from ordinary setae elsewhere; fourth and fifth segments elongate cylindrical, fifth segment 1.6 times as long as fourth segment.

Thorax. Anepisternum with 2–3 setae in upper portion, other pleura non-setose. Legs. Antero-apical depression of fore tibia with distinct semicircular rim, bearing 20–25 non-socketed, stiff setae; apical setae arranged in line. Wing. Sc entering C well before level of ta. Sc-r very weak. R1 entering C well beyond level of M-furcation. A1 reaching wing margin. A2 absent.

Terminalia. Ninth tergite with broadly rounded apical margin, bearing setae of various sizes. Gonocoxites ventrobasally interlinked through membranous, non-setose portion, otherwise bearing setae of various sizes. Gonostylus rather stout, bearing apically strong double-tooth; tooth half as long as gonostylus body, tooth width at base 0.35 times its length ( Fig. 2 C). Aedeagus with rod-like apodeme, the latter apically funnellike and bearing numerous long trichia. Parameres fused to form tegmen; tegmen apically rounded, with weak contours; parameral apodemes strong. Hypoproct large, apically incised, bearing 1 large seta on either side. Cerci as large as hypoproct, bearing apically and dorsally setae of various sizes.

Female. Body length 3.0– 3.1 mm. Head. First flagellomere 2.6 times as long as wide. Fourth flagellomere 1.7 times as long as wide.

Thorax. Anepisternum bearing 0–3 setae. Legs. Tarsus of fore leg not enlarged; three distal tarsomeres bearing sole of dense, stiff setae.

Terminalia. Cercus somewhat widened subapically ( Fig. 2 E).

Discussion. The first antennal flagellomere in hybrida is short, as is typical of the subgenus Diadocidia s. str., while the anepisternum is setose, as is typical of Adidocidia . As regards male terminalia in hybrida , the gonostylus is Diadocidia s. str. -like in having its apex slender and bifurcate for just a short distance, while the ninth tergite is Adidocidia -like in lacking spine-like setae at its apex. Female terminalia are Adidocidia -like in that the cercus is somewhat widened subapically. This adds up to a mixed constellation of features, so that hybrida cannot be classified to either Diadocidia s. str. or Adidocidia . It cannot be assigned to the subgenus Taidocidia either, because in globosa, its only species, the subcosta enters the radius, not the costa, and the gonostylus is peculiar in bearing apically a comb of thick, short macrosetae ( Papp & Ševčik 2005). Apparently, the subgeneric classification of Diadocidia needs reassessment, which should be addressed further once the extra-Holarctic fauna of diadocidiids becomes better known.

Etymology. From Latin, hybridus, hybrid, referring to the peculiar mix of characters.

Types. Holotype. Male (on slide). Costa Rica, Guanacaste province, Nandayure, Bellavista, Cerro Azul, alt. 1050 m, 1 May–19 July 2003, by Malaise trap, W. Porras & D. Briceño (INBio sample #74645). Paratypes. 4 males, 2 females, same data as the holotype.

Other material. 51 males, 4 females (all in ethanol), same data as the holotype.

Figures

FIGURE 2. Morphology of Diadocidia spp. A: Male antennal flagellomeres 1 – 4, lateral view, of D. hybrida sp. n. (holotype). B: Male antennal flagellomeres 1 – 4, lateral view, of D. similis sp. n. (holotype). C: Gonostylus, ventral view, of D. hybrida sp. n. (holotype). D: Male terminalia, ventral view, of D. similis sp. n. (holotype). E: Apex of ovipositor, lateral view, of D. hybrida sp. n. (paratype). Scale = 0.1 mm (A, B and E) and 0.05 mm (C and D).