Dioscoridus depressus Popov, 1957

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

Dioscoridus depressus Popov, 1957

Figs 27 , 28 , 29

References for Socotra.

Popov (in Uvarov and Popov (1957)): 373–374, fig. 23; Guichard 1992: 185; Wranik 2003: 321, plates 153, 155.

Diagnostic notes.

Dioscoridus depressus is readily identifiable by several distinct characteristics: it is entirely apterous, with a conspicuous yellowish to light brown central longitudinal line from the fastigium to the tip of the abdomen. Two irregularly swollen ridges on the pronotum’s sides represent the lateral carinae. It features a well-defined, large tympanum (Figs 27 , 28 ).

Taxonomic notes.

The genus is named after Dioscorida, the name of Socotra in Sanskrit, meaning the island of the abode of bliss ( Schoff 1912). Popov (in Uvarov and Popov (1957)) stated that the genus stands alone within the Catantopinae , without an apparent near relative, apart from some superficially resembling African bush-dwelling genera.

Distribution and occurrence.

Dioscoridus is endemic to Socotra. Records are mainly from the Hagher and the surrounding limestone plateaus, but singletons in the west at Shuab suggest a much wider distribution (Fig. 29 ). It is considered uncommon, but may be easily overlooked due to its partially hidden way of life.

The labels of the specimens collected by Guichard on Mt. Shihali mention an elevation of 1500 m a. s. l. Since the peak of this mountain reaches 1324 m a. s. l., this is a mistake. Furthermore, Guichard’s field notes (1967) show he visited “ the mountain’s lower slopes ” on 20 April 1967, not the mountain’s peak. Based on this information and our knowledge of the area, we estimate the collecting site of these specimens to be more or less around 1100 m a. s. l. in an area much closer to Adho Dimello.

Habitat and biology.

Records of Dioscoridus are from high shrubland with succulents, submontane shrubland, Dracaena woodland and forest, montane mosaic and forest. Adults and nymphs live under and in cracks of the bark of dead trees, under stones and on open ground (Popov in Uvarov and Popov (1957)). Guichard (1992) found several adults under the bark of dead trees, side by side with geckoes. The species is present year-round; nymphs were found in February, March and October. Records are from 10–1100 m a. s. l.

Figures

Figure 27. Dioscoridus depressus Popov, 1957, female. Dineghen, Socotra, 494 m a. s. l., 1 Nov 2010 (photograph Robert Ketelaar).

Figure 28. Dioscoridus depressus Popov, 1957, male, holotype. Dixam Plateau in 1953. Scale bar: 1 cm (photograph Rob Felix).

Figure 29. Distribution of Dioscoridus depressus Popov, 1957 in the Socotra Archipelago.