Cesathrix
Ordo: Diptera
Familia: Sciaridae
Name
Ceathrix Koçak & Hüseyinoğlu, 2008 valid – ZooBank link
- Cesathrix Koçak & Hüseyinoğlu, 2008[1]: 2 – replacement name for Pterothrix Mohrig, 2003
- Pterothrix Mohrig, 2003[2]: 11 – homonym (non Pterothrix Nees, 1837: 409 [3]) – type species: Pterothrix piliata Mohrig, 2003
Description (male)
Head. Eye bridge 3–4 rows of facets. Transition of basal part to neck pronounced. Palpomeres 1–2. First palpomere thickened, with numerous setae; with only some sparse sensillae. Thorax. Posterior pronotum bare. Laterotergite bare. Legs. Frontal tibia with a patch of setae. Front tibial organ mostly dark, not bordered. Tibial spurs elongate, of equal length. Claws untoothed. Wings. dark, of normal shape. Wing membrane completely covered with macrotrichia. Wing venation normal. M-fork of normal shape. R1 inserting at or slightly before base of m-fork; posterior veins with macrotrichia. Abdomen. Abdominal setae strong and dense. Hypopygium concolour with abdomen. Inner margin of gonocoxites U-shaped; inner membrane of hypopygium bare. Gonostylus elongate; inner margin concave. Apical tooth present. Megasetae on inner part of gonostylus present. Tegmen rounded; central process absent. Measurements. Body size 3–4 mm. Wing length 3–4 mm.
Diagnosis
Cesathrix is placed in the basal subfamily Sciarinae together with Sciara, Trichosiopsis and Trichosia. These genera are characterized by setose wing veins and a patch of numerous setae on the inner side of the apex of the fore tibia (tibial organ). Characteristic for the genus are the short palpi and the completely trichose wing membrane. A completely trichose wing membrane is also present in Hirtipennia and some species of Trichosia. Hirtipennia does also possess an apical tooth at the gonostylus. Contrary to Trichosiopsis, Hirtipennia and Leptospina no strong awl-like setae are present, but instead of that elongate spines (megasetae). The reduced palpi distinguish Cesathrix from all other Sciarinae.
DNA Barcoding
Due to the combination of hairy wings and the reduced palpi it was possible to confidently identify a bunch of related BINs by photos on BOLDSYSTEMS:
BOLD:ACS8096 (average distance 0.18%, n=2, K2P: 13.98%).
BOLD:ACT5913 (average distance 0.02%, max. 0.18%, n=14, K2P: 15.47%).
BOLD:ACT6884 (average distance 0.16%, max. 0.39%, n=6, K2P: 10.39%).
BOLD:ACY9862 (average distance 0.00%, n=2, K2P: 13.08%).
BOLD:ADA2021 (n=1, K2P: 10.39%).
BOLD:ADC0009 (average distance 1.08%, n=2, K2P: 13.73%).
BOLD:ADL6512 (n=1, K2P: 11.11%).
BOLD:ADM1519 (n=1, K2P: 15.41%).
Discussion
Mohrig (2003)[1] discussed a proximity of this genus with Scythropochroa, especially with Scythropochroa multispinosa based on the reduced palpi and the similarity of the gonostylus. A closer relation to Scythropochroa mutispinosa is not impossible, only that species is probably not belonging to Scythropochra but to a still undescribed genus. Based on the still fragmentary genetic information of the putative Cesathrix species this genus is very isolated from other Sciaridae and might therefore belong to a very basal clade of the family. The barcoded species are as well genetically isolated from one another and on the other hand obviously not very common.
Distribution
The distribution of Cesathrix is currently restricted to Central America.
Species list
Cesathrix capillosa - Cesathrix piliata
References
- ↑ 1.0 1.1 Koçak, A.Ö.; Hüseyinoğlu, Y. 2008: Nomenclatural notes on the genus group names in the order Diptera (Tabanidae, Sciaridae). Centre for Entomological Studies Ankara miscellaneous papers, 143, 1–2.
- ↑ Mohrig, W. 2003: Black fungus gnats of Central America. Part I. (Diptera, Sciaridae). Beiträge zur Entomologie, 53(1), 1–69.
- ↑ Nees von Esenbeck, C.G. 1837: Hymenopterorum Ichneumonibus affinum Monographiae. 2, Stuttgart & Tübingen, 488 pp. BHL doi 10.5962/bhl.title.26555
