Gymnoscirtus unguiculatus Karsch, 1888

Hemp, Claudia, 2013, Annotated list of Tettigoniidae (Orthoptera) from the East Usambara Mountains Tanzania and new Tettigoniidae species from East Africa, Zootaxa 3737 (4), pp. 301-350 : 333

Gymnoscirtus unguiculatus Karsch, 1888 ( Fig. 23 )

http://lsid.speciesfile.org/urn:lsid: Orthoptera .speciesfile.org:TaxonName:13542

Karsch (1888b) described Mecopoda unguiculatus and erected a few years later the monotypic genus Gymnoscirtus (Karsch 1891) . Gymnoscirtus is characterized by an elongated but stout body of mostly brown or greenish colour with antennae that are about 1.5 times as long as the body length. Gymnoscirtus has a broad fastigium verticis, which meets the fastigium of frons in a broad well distinguished horizontal line with a deep median sulcus. The pronotum has deep lateral lobes, the disk of the pronotum shows a typical hourglass shape, bordered lateral at the upper parts of the lobes by shiny black areas in the males. The prosternum is bispinose with a pair of slender and long slightly backward curved spines. Gymnoscirtus is brachypterous with the tegmina partly covered by the pronotum, while females have small lobes laterally protruding from the posterior margin of the pronotum and which are not overlapping. Hindwings are lacking in both sexes. The abdominal tergites wear rounded knobs medially. Fore coxa with well developed spine. The legs are long and slender, the hind femora stout at their base, surpassing the apex of the abdomen about half of their length. The hind tibiae are longer than the hind femora. The male cerci are short but slender and slightly curved inward. The subgenital plate, as typical for most Mecopodinae , is elongated and fork-like incised medially at posterior end. The ovipositor of the females is moderately long, stout at the base and slender and laterally compressed along the remaining part, of about half the length of the hind femora, and slightly up-curved..

Diagnosis: Gymnoscirtus is very similar to the West African genus Apteroscirtus . Characters differentiating the two genera as given by Karsch (1891) are a fastigium verticis which is broader in Gymnoscirtus , the form of the pronotum which is constricted at its first furrow (causing the “hourglass” shape), and the subgenital plate which is triangularly incised in Apteroscirtus while the incision is evenly rounded in Gymnoscirtus .

Distribution: Tanzania: East and West Usambara Mountains, Gendagenda Forest Reserve, Uluguru Mountains, Nguru Mountains, Pugu Hills. Kenya: Mrima Hill, Shimba Hills.

Ecology & Biology: G. unguiculatus is day active, well camouflaged among leaf litter of the forest floor.

Habitat: Coastal and lowland, submontane to montane forest from about 50 to 1600 m.

Remarks: The individuals in the collection of the NHM London from the Pugu Hills, the Uluguru and Nguru Mountains of Tanzania show slight differences in the outer genitalic apparatus and the shape of the spines of the prosternum. Further studies on a larger series of specimens from these localities on morphology, song and genetics have to show whether further species of Gymnoscirtus occur in these mountains.

Figures

FIGURE 23. Male Gymnoscirtus unguiculatus, Mazumbai Forest Reserve, West Usambara Mountains.