Glomeremus capitatus Uvarov, 1957

Glomeremus capitatus Uvarov, 1957 View in CoL

Figs 185 View Figure 185 , 186 View Figure 186 , 187 View Figure 187 , 188 View Figure 188 , 189 View Figure 189 , 190 View Figure 190

References for Socotra.

Uvarov (in Uvarov and Popov (1957)): 361–362, fig. 3; Popov 1984: 197, fig. 73; Wranik 2003: 312, plate 148; Cadena-Castañeda 2019: 55, 84.

Diagnostic notes.

Raspy Crickets ( Gryllacrididae ) are plump, non-jumping crickets with soft, fleshy bodies and nocturnal behaviour. They are often sandy-coloured (Fig. 185 View Figure 185 ).

Glomeremus capitatus resembles G. pileatus in almost all aspects, including the male abdominal terminalia. The main characteristics of G. capitatus are the typical black pattern on the pronotum and more extensive black markings on the antennae, abdominal tergites and legs (Fig. 187 View Figure 187 ), compared to G. pileatus . There are subtle differences in the genital plate in males of both species: rounded mainly with a slightly truncated apex in G. capitatus and trapezoid in G. pileatus (Fig. 188 View Figure 188 ). In females, there is a clear difference in the subgenital plate. In G. capitatus , females have elongated lobes with a rounded apex. In G. pileatus , they are much shorter, square and sharply notched (Fig. 189 View Figure 189 ).

The width of the head is not a good characteristic for separating both species, contrary to Uvarov (in Uvarov and Popov (1957)) and Popov (1984). In both species, the head is wider than the pronotum.

Uvarov (in Uvarov and Popov (1957)) and Popov (1984) state that, contrary to G. pileatus , G. capitatus does not have stridulatory pegs on the side of its tergites. However, an examination of the specimens G. capitatus collected at Skand and Zerig in 2012 shows the presence of those pegs on the second and third tergites, both in males, females and late instar nymphs.

Taxonomic notes.

Uvarov (in Uvarov and Popov (1957)) based his concise species description of Glomeremus capitatus on a male collected at Dixam Plateau by Popov in 1953. We presume this holotype to be a late instar nymph, based on its size (18 mm), general colouration and the apparent absence of well-developed styli at the posterior margin of the subgenital plate, as judged from the depicted photographs (only cerci are present) (Fig. 186 View Figure 186 ).

Czech entomologists collected an adult male and female specimen in 2012 (Fig. 187 View Figure 187 ). The male body is much larger (25 mm) than the holotype’s body and the degree of black markings on the abdomen and legs is much more extensive. The male has two well-developed styli on the hind margin of the subgenital plate (Fig. 188 View Figure 188 ).

Here, we give a concise re-description of the male, with additional characteristics missing in the original species description (Uvarov in Uvarov and Popov (1957)) and a brief description of the female.

Re-description.

Male: moderate size, body sandy-coloured with extensive black markings, shiny, eyes black. The posterior margins of the mesonotum, metanotum and abdominal segments are broadly marked black. The femora laterally and ventrally are extensively marked black and the tibiae, dorsally, have a black spot near their base. Lip sandy-coloured, jaws black, paler towards the base. The antennae are four times as long as the body, the two basal segments are sandy-coloured and from the third segment onwards, the antennae display a colour transition from blackish to dark brown and yellowish (Figs 185 View Figure 185 , 187 View Figure 187 ). The posterior margin of the subgenital plate is essentially convex with a slightly truncated apex, ventrally with a depression in the centre (Fig. 188 View Figure 188 ).

Female: same as male, except large size, much larger than male. Ovipositor elongate and rather thick, acuminate; the lower margin is almost straight and the upper slightly arched upwards (Fig. 187 View Figure 187 ). The subgenital plate in the female is triangular, anteflexed and bifid at the apex, with elongated slender lobes (Fig. 189 View Figure 189 ) — Body length male: 23 mm; female: 33 mm; ovipositor: 18 mm.

Both are based on only one specimen each, so we recommend a future examination of a small series of specimens.

Distribution and occurrence.

Endemic to Socotra. Apparently, it is rare and local and confined to Dixam and the Hagher. Popov collected the holotype “ between RAF camp and Muhullus ”. The map in Uvarov and Popov (1957) shows the route Popov travelled in 1953, between the RAF camp in the north and Mahalis in the south, crossing Dixam at a point around 3000 feet (914 m a. s. l.). We expect the collecting site to be near that site (Fig. 190 View Figure 190 ). Other Orthoptera specimens collected that day by Popov bear the label “ 10 miles south of RAF Camp ”, which fits the above site description.

Habitat and biology.

Only found in higher elevations (700–1450 m a. s. l.). The habitat at the type locality at Dixam is supposed to be submontane shrubland or Dracaena woodland. At Mount Skand, the Czechs collected the species in a montane forest. Where these specimens were collected is unknown: inside shrubs or on / under the ground. It is a nocturnal species like all Gryllacridids. The records are from March and June.

Bioacoustics.

All gryllacridids produce sound by a femoral-abdominal stridulatory apparatus, formed by parallel rows of pegs on the lateral side of tergites and a row of pegs on the adjacent inner side of the hind femora. Sound producing is only used as a defence if the crickets are threatened. Tympana are absent in this cricket family ( Rentz and John 1989).