Diadocidia (Adidocidia) nigripalpis Edwards, 1940

Jaschhof, Mathias & Jaschhof, Catrin, 2007, On the genus Diadocidia (Diptera, Sciaroidea, Diadocidiidae) in Costa Rica, Zootaxa 1586, pp. 33-38 : 34-35

Diadocidia (Adidocidia) nigripalpis Edwards, 1940

( Fig. 1 )

Characters. The first antennal flagellomere bears dorsally a few socketed setae, apart from the non-socketed setae that are somewhat shorter and cover the node entirely. The maxillary palpus is five-segmented, with the third segment elongate, a little longer and thicker than the second segment and bearing a very few short hyaline sensilla on its mesial surface. The aedeagus consists of a rod-like sclerotized apodeme that is widened and bearing numerous long trichia apically; this spatulate widening extends dorsally into a voluminous membranous portion that merges almost imperceptibly with the hypoproct ( Fig. 1 C). The hypoproct, discernible by the two setae on either side, is apically two-pointed and laterally strong, thereby giving the entire structure the clear contours that otherwise might be mistaken for the lateral margins of the tegmen ( Figs 1 A and C).

As suggested by both Laštovka and Matile (1972) and Papavero (1977), nigripalpis should be classified with Adidocidia , which is based on the following characters: the anepisternum bears five to six setae on its dorso-anterior margin; the first antennal flagellomere is four or more times longer than wide; the apical margin of ninth tergite does not bear spine-like setae; the gonostylus has a broad and deeply bifurcate apex ( Fig. 1 B); the anterior tarsus of female is not enlarged; and the female cercus is somewhat widened subapically ( Fig. 1 D).

The gonostylus in nigripalpis is diagnostic in bearing subapically two large macrosetae ( Fig. 1 B). Compared with the other species classified with Adidocidia , nigripalpis comes closest to the Nearctic D. borealis Coquillett (with one short macroseta subapically on the gonostylus), and D. valida Mik (with one long macroseta in some distance from the apex of gonostylus) and D. trispinosa Polevoi (with three moderately long and thin macrosetae on the mesial surface of gonostylus), both Palearctic. As regards the female terminalia, nigripalpis and borealis are similar in bearing five or so spines dorso-subapically on the cercus, which are absent in valida (the female of trispinosa is not known). These spines are larger in nigripalpis than in borealis (see Laštovka & Matile 1972: fig. 23). Altogether, nigripalpis and borealis appear to be sister species.

Discussion. Specimens from Costa Rica are unquestionably conspecific with the type specimens of nigripalpis from Brazil. In two male specimens from Costa Rica with complete antennae, the first flagellomeres are four times as long as wide and thus slightly shorter than in the male syntype specimen. The balsammounted terminalia of the latter are very pale, which makes perception of structural details of the aedeagustegmen complex difficult.

Material studied. 1 male (on slide), Costa Rica, Cartago province, Finca los Lagos, Madreselva, alt. 2600 m, December 1993, by Malaise trap, M.M. Chavarria ( INBio sample #2602); 1 male, 1 female (both on slides), Cartago province, Parque Nacional Tapantí-Macizo de la Muerte, Estación La Esperanza, alt. 2200- 2600 m, 3–22 November 2003, by Malaise trap, M. & C. Jaschhof; 1 male (pinned, with terminalia mounted on a plastic sheet in Canada balsam, labelled “ Type ”), “ Brasilien, Nova Teutonia, 27°11’B/52°23’L, 10.7.1938, Fritz Plaumann” (Brit. Mus. 1938-682, BMNH (E) #253409); 1 male (pinned, with terminalia in glycerol, labelled “ Syntype ”), same data as previous specimen but “ 9.7.1939 ” (Brit. Mus. 1939-628, BMNH (E) #253410); 1 female, abdomen missing (pinned, labelled “ Syntype ”), same data but “ 9.6.1939 ” ( BMNH (E) #253411).

Figures

FIGURE 1. Diadocidia nigripalpis Edwards. A: Male terminalia, ventral view (specimen from Madreselva, Costa Rica). B: Gonostylus, ventral view (same specimen). C: Aedeagus, tegmen, hypoproct and cerci, ventral view (same specimen). D: Female terminalia, lateral view (specimen from La Esperanza, Costa Rica). Scale = 0.05 mm (B and C), 0.1 mm (A), and 0.2 mm (D).