Asynapta Loew, 1850

Jaschhof, Mathias & Jaschhof, Catrin, 2019, New and rarely found species of asynaptine Porricondylinae (Diptera: Cecidomyiidae) in northern Europe, Zootaxa 4604 (2), pp. 281-300 : 284

Asynapta Loew

The taxonomy of Asynapta in Europe was revised three times in the past few decades ( Panelius 1965: 72; Spungis 1988; Jaschhof & Jaschhof 2013: 312ff.). As a result, 17 European species have been recognized, including several with Holarctic distributions ( Gagné & Jaschhof 2017). Oddly enough, the type species, Cecidomyia (Asynapta) longicollis Loew is the only Asynapta in Europe whose identity remains unresolved (see Panelius 1965: 75f.; Jaschhof & Jaschhof 2013: 312). While purposeful search for Asynapta in parts of northern Europe had earlier revealed the occurrence of 13 different species, three new species from Sweden and Finland are added here to the Nordic fauna. At the same time, one species is recognized as a synonym, so that a total of 15 different Asynapta are now known to be present in the region.

As has been pointed out earlier, the copulatory organ of Asynapta is a complex structure that, given its tininess, complexity and weak sclerotization, is difficult to study using transmitted-light microscopy ( Jaschhof & Jaschhof 2013: 314). Its construction was reexamined in the course of the present study and is reinterpreted here as follows. Both ventral and dorsal parameres are present, with the ventral parameres exhibiting a wide range of completely different shapes (see, for example, Figs 3 and 4 ), and with the dorsal parameres, previously believed to represent the greatly extended aedeagal apex, completely merged to form a tegmen ( Fig. 3 ). As an indication of its parameral rather than aedeagal origin, the tegmen has anterolateral apodemes for the attachment of muscles and is connected with the gonocoxae via lateral bridges ( Jaschhof & Jaschhof 2013: fig. 158B). The aedeagal apodeme, which lies in between the ventral and dorsal parameres, is usually vestigial and only in some species clearly discernible. In A. saliciperda Felt , for instance, the apodeme is a distinctive, sclerotized rod that transitions into a faintly darkened, bifurcate structure, which represents the visible portion of the otherwise completely transparent aedeagal apex ( Jaschhof & Jaschhof 2013: fig. 159B); the aedeagal apex and tegmen appear to be completely amalgamated here. In most other species of Asynapta , the only vestige visible of the aedeagus is a faint, reverted V- or arrow-shape, which indicates the presence of the ejaculatory gland ducts entering the posterior end of the aedeagal apodeme ( Fig. 3 ; Jaschhof & Jaschhof 2013: fig. 158B).

Figures

FIGURES 1–4. Genitalic morphology of Asynapta spp. 1: Gonostylus of A. inflatoides, ventral, paratype. 2: Gonostylus of A. rickebasta, ventral, holotype. 3: Aedeagus and parameres of A. rickebasta, ventral, holotype. 4: Genitalia of A. taigensis, ventral, holotype. Scales for 1–3, 0.025 mm, for 4, 0.05 mm. Arrows refer to characters described in the diagnoses.