Gabyella
Ordo: Diptera
Familia: Sciaridae
Subfamilia: Sciarinae
Name
Gabyella unpublished
Description (male)
Head. Antenna unicolour. Transition of basal part to neck pronounced. Antennal setae shorter than segment width or as long as segment width. Palpus short; palpomeres 2 or 3 with reduction tendency. First palpomere thickened with only sparse sensillae. Thorax. Thoracic setae normal. Posterior pronotum bare. Mesothoracic sclerites bare or with bristles. Legs. Front tibia apically with a patch of setae. Front tibial organ not bordered. Tibial setae on hind legs inconspicuous, shorter than tibial width. Tibial spurs of equal length. Claws untoothed. Wing. Wing reduced, with weakly developed anal lobe. Wing membrane without macrotrichia. Wing venation weak, with faint stM. M-fork of normal shape. R1 ending at or slightly before base of m-fork; posterior veins bare. Halter darkened; of normal length. Abdomen. Abdominal setae strong. Hypopygium concolour with abdomen. Base of gonocoxites with normal, weak hairs; gonocoxites broadly separated; inner margin of gonocoxites normally U-shaped; inner membrane of hypopygium scarcely setose; elongated setae on gonocoxites absent. Gonostylus elongate; inner margin concave; apical tooth present, without internal structure, strong. Awl-like setae long numerous on inner side of gonostylus, reaching far beyond the tooth. Subapical megasetae absent. Tegmen 0.6–0.75 × longer than broad; equally rounded or rectangular with rounded edges. Field with aedeagal teeth inconspicuous.
Diagnosis
By the tibial organ formed as an undifferentiated patch of setae and the long R5 Gabyella is placed into the basal subfamily Sciarinae. From general aspect the new genus is similar to Trichosiopsis, Leptospina, Neozygoneura and Hirtipennia. All these genera share the presence of an apical tooth at the gonostylus with specialized setae above and beneath of it. The following characters distinguish the new genus: apical setae at gonostylus longer and finer and not strong and short (awl-like); palpus with first segment thickened and a tendency towards reduction of the following segments; posterior pronotum bare; wings reduced, without anal lobe and posterior wing veins without macrotrichia; tegmen not rectangular. Members of Leptospina neither possess macrotrichia on the posterior wing veins, but have instead strongly developed awl-like setae. The Neotropical genus Neozygoneura, also without macrotrichia, can be distinguished by the bottle-neck like neck of the flagellomeres and the more elongate gonostylus. Gabyella is probably also related to Trichodapus, because of the presence of elongate setae at the gonostylus, reduced wings and the palpus having a swollen, first segment. The type species of Trichodapus, Trichodapus subvagulus and the similar Trichodapus conjunctivus additionally have no macrotrichia on the posterior wing veins, a bare posterior pronotum and a rounded tegmen. Trichodapus rhenanus, which is included currently as well in Trichodapus, has an apical tooth at the gonostylus, some macrotrichia on the posterior wing veins and bottle-neck like antennal necks. It is therefore very probably not congeneric with both above mentioned species of Trichodapus. Gabyella can be distinguished from Trichodapus in its restricted sense (including only T. conjunctivus and subvagulus) by the presence of a clearly developed apical tooth at the gonostylus and non-elongate legs and halters (except for the poorly known G. dolichocorpa).
Etymology
The genus is named in honour of Gaby Heller for supporting the author and his scientific work during 20 years.
Discussion
Nine species are currently assigned to Gabyella. The designated type species, G. hanne, is COI-sequenced and is represented by BIN BOLD:ADD2554. It is currently the nearest neighbour to G. orientalis from China with a genetic distance of 13.8 %. Interestingly these species and the four Gabyella species from Canada are very isolated from most other Sciaridae with respect to their COI-sequence. The next closest matches belong to different families (Cecidomyiidae) and even different orders (Lepidoptera).
Gabyella appears to have a Holarctic/Oriental distribution and all species are very rare, contrary to the species rich and usually abundant genus Trichosiopsis with lots of similar and cryptic species, which therefore seems to have experienced a more recent radiation. It is tentative to assume, that Gabyella is a more ancient, relict lineage and possibly a very basal member of Sciaridae and might even constitute a different subfamily.
Some species of other genera show superficial affinities to Gabyella. Trichosiopsis helvetica has also numerous and elongate awl-like spines at the gonostylus, but the wings have macrotrichia and the palpi and tegmen are typical for Trichosiopsis. Similarly some Oriental species such as Trichosiopsis ironica have also elongate and numerous awl-like spines at the gonostylus and may represent another separate genus. The species Scythropochroa multispinosa, which was formerly supposed to be close to G. opaca by Heller (2012: 192)[1], is no longer considered to be belonging to this genus and neither to Trichosiopsis. It is for the moment placed back into Scythropochroa, as it was already discussed in detail by Mohrig (2004: 139)[2].
Distribution
Holarctic and Oriental Region
Species list
Gabyella angustipennis - Gabyella dolichocorpa - Gabyella hanne - Gabyella inae - Gabyella minuta - Gabyella mediopalpus - Gabyella neoopaca - Gabyella opaca - Gabyella orientalis
References
- ↑ Heller, K. 2012: Fünf neue europäische Arten von Trauermücken (Diptera, Sciaridae) aus dem Artenkreis um Leptosciarella pilosa. Veröffentlichungen des Museums für Naturkunde Chemnitz, 35, 91–102.
- ↑ Mohrig, W. 2004: The black fungus gnats (Diptera: Sciaridae) of Papua New Guinea. Part II - genera Scythropochroa, Cratyna, Pseudozygomma, Epidapus, Hyperlasion, Corynoptera, Keilbachia, Scatopsciara, Pelliciplanta gen. nov., and Pseudozygomma gen. nov. Studia dipterologica, 11, 129–174.
