Glomeremus pileatus ( Krauss, 1902 )

Felix, Rob, Bouwman, Jaap, Odé, Baudewijn, Ketelaar, Robert, Pham, Duc Minh & Bailey, James, 2025, The grasshoppers and crickets (Orthoptera) of the Socotra Archipelago (Yemen): a comprehensive overview and a description of a new Oecanthus Tree Cricket (Oecanthidae), Contributions to Entomology 75 (1), pp. 21-166 : 21-166

Glomeremus pileatus ( Krauss, 1902)

Figs 188 , 189 , 191 , 192 , 193 , 194

References for Socotra.

Krauss 1902: 5 [as Eremus pileatus ]; Krauss 1907: 17, 26, 30, plate II: figs 9, 9 A – D [as E. pileatus ]; Griffini 1914: 245 [as Neanias pileatus ]; Uvarov (in Uvarov and Popov (1957)): 359, 361, figs 1–2; Popov 1984: 197–200, figs 71, 72, 78, 79; Wranik 1998: 173; Wranik 2003: 313, plates 145, 148; Massa 2009: 55, figs 1–6; Cadena-Castañeda 2019: 55, 84.

Diagnostic notes.

Glomeremus pileatus ( Krauss, 1902) is characterised by a typical pattern of two bands in the middle of the pronotum (Figs 191 , 192 , 194 ). This pattern is quite variable (Uvarov in Uvarov and Popov (1957); Massa 2009). In some specimens, the markings are pitch black; in others, they are rufous, as mentioned for the type specimen or even faded. The same applies to other body markings like legs or abdomen. A population that may belong to G. pileatus occurs in dunes near Arher, but features little to no dark pigmentation.

Contrary to what Popov (1984) stated in his key to the species of Glomeremus of Socotra, the stridulatory pegs are on the 2 nd and 3 rd tergites, not the 1 st and 2 nd. Furthermore, in G. pileatus , the head is also clearly wider than the pronotum, as depicted in, for example, figs 1–2 in Massa (2009). The width of the head is not a good character to separate the species from G. capitatus .

In comparing Popov’s material with Krauss’s description, Uvarov (in Uvarov and Popov (1957)) noticed that the ninth tergite in the male is not convex behind, but decidedly truncated. The same is true in our material (Fig. 188 ). For further characteristics, see G. capitatus .

Taxonomic notes.

Krauss (1902, 1907) gives the following species description [translated from Latin]: “ Small, ochraceous, occiput and fastigium of the vertex covered with a black, shiny, subtriangular spot, like a cap. The fastigium of the vertex is scarcely wider than the first antenna segment. Smooth forehead, shiny. Lip rufous, jaws black, paler towards the base. Antennae half as long as the body [probably broken in the type specimen, since in specimens studied by us, they are more than twice as long as the body], rusty, the two basal joints are ochreous, the third joint is black brown. Pronotum short, with rounded corners. A large central transverse rusty spot ornaments the centre of the pronotum; sometimes decorated with some black spots on the lateral side of the rusty spot. Mesonotum on the anterior margin, metanotum on the posterior margin marked by two chestnut spots. Femora rusty-coloured, underside with a black semi-lunar spot in front of the apex, underside hind femora with black spines, 2–5 on the inner margin, 1–5 on the outer margin. Tibiae dorsally with a black spot near their base. Abdominal tergites with black posterior marginal bands. Ninth abdominal tergite in male semi-lunar, convex, posteriorly arched. Subanal valves expanded transversely on the inner margin armed with black, hooked spinules. Subgenital plate in male semi-lunar, posteriorly arched, equipped with a stylus on both sides; in female, triangular, anteflexed, bifid at the apex, with obtuse lobes. Ovipositor rusty, slender, elongate, acuminate, the lower margin almost straight, the upper broadly arched, the apex suddenly ascending, almost hooked. Body length male 16 mm, female 22–27 mm, ovipositor 10 mm ” (Fig. 192 ).

We suspect the male type was a nymph, based on the small size of the male (16 mm) mentioned in the species description ( Krauss 1902; 1907). Some of the specimens we studied are much larger (26 mm).

The type specimens, one male and two females collected at Shuab, have been lost, as stated by Uvarov (in Uvarov and Popov (1957)) and confirmed by the museum in Vienna (H. Bruckner in litt.). G. pileatus deserves the designation of an adult male neotype, preferably from the western part of Socotra. At the same time, a female should be collected, preferably during mating. Both should be re-described. Since the possible existence of one or several (cryptic) species besides G. pileatus , this will prevent later confusion.

Distribution and occurrence.

Endemic to Socotra. Relatively widespread and not as rare as mentioned by Uvarov (in Uvarov and Popov (1957)) and Wranik (2003) (Fig. 193 ). Glomeremus spp. are called Brothers of the Goats in Socotri ( Wranik 2003), suggesting a relatively common appearance on the island.

Habitat and biology.

Nocturnal. In 2009 and 2010, they were found in various habitats, during the day under stones and at night in shrubs, like Croton socotranus and Jatropha unicostata (Fig. 194 ). G. pileatus occurs in all vegetation types, except montane forests and shrubland in the high Hagher. They are recorded nearly year-round at elevations from 5–350 m a. s. l.

Bioacoustics.

See G. capitatus .

Figures

Figure 188. Terminalia of male Glomeremus spp. from Socotra. A, B. G. capitatus Uvarov, 1957; C, D. G. pileatus (Krauss, 1902); E, F. Glomeremus mediopictus Uvarov, 1957. A, C, E. Male tergite IX, hooks on the hind margin of tergite X, cerci, subgenital plate with styli; B, D, F Male subgenital plate with styli (photograph Rob Felix).

Figure 189. Subgenital plates of female Glomeremus spp. from Socotra. A. G. capitatus Uvarov, 1957; B. G. pileatus (Krauss, 1902); C. Glomeremus mediopictus Uvarov, 1957. The first two species show an anteflexed, bifid structure (A, B), while the last species shows a swollen transverse ridge (C) (photograph Rob Felix).

Figure 191. Glomeremus pileatus (Krauss, 1902), female. Ditwah, Socotra, 8 Feb 2024 (photograph James Bailey).

Figure 192. Illustrations of Glomeremus pileatus (Krauss, 1902) accompanying the species description. A. Habitus; B. Dorsal view of head and pronotum; C. Abdominal terminalia of the male; D. Ventral view of abdominal terminalia of the female (Krauss 1907).

Figure 193. Distribution of Glomeremus pileatus in the Socotra Archipelago.

Figure 194. Glomeremus pileatus (Krauss, 1902), copulating pair. Ditwah, Socotra, 28 Feb 2009 (photograph Rob Felix).