Sphingonotus (S.) ganglbaueri Krauss, 1907

Figs 90, 91, 92, 93

References for Socotra.

Krauss 1907: 21, 29, plate II: fig. 4; Mistshenko 1937: 155; Popov (in Uvarov and Popov (1957)): 377; Wranik 1998: 171; Wranik 2003: 323, plates 152, 157.

Diagnostic notes.

Sphingonotus (S.) ganglbaueri is often a whitish or pearl-coloured species, characterised by a slender body and an acutely-angled posterior margin of the pronotum. A broad pale medial band on the forewing is often lighter than the overall base colour and contrasts strikingly in darker specimens (Figs 90, 93). Base colouration adapts locally, such as brick-red specimens occurring at Dehamd amongst similarly coloured soils. The hind wings are hyaline with bluish veins, sometimes with a faint, bluish base. There is often a trace of a dark fascia, mainly in males.

Taxonomic notes.

Krauss (1907) described S. (S.) ganglbaueri, based on a single male collected on Socotra by Simony in 1899. Mistshenko (1937) re-described the species and Popov (in Uvarov and Popov (1957)) described the female.

Distribution and occurrence.

The species is endemic to the Socotra Archipelago and occurs on Socotra and Samha Is. It is widespread and locally common on Socotra, especially on the coastal plains below 70 m a. s. l. (Fig. 91). There are exceptional records up to 700 m a. s. l. (see Popov in Uvarov and Popov (1957)), as in Wadi Dineghen in 1956 and Di Hashus and Betin in 2008. In 2009, it was common at Ditwah Lagoon and on Noged Plain.

Habitat and biology.

S. ganglbaueri can be found on dry, bare patches of gravelly and sandy soils on the coast in dunes (Fig. 90), sparse dwarf shrubland, low Croton - Jatropha shrubland and high shrubland with succulents and, occasionally, in more vegetated areas. It is recorded year-round.

Bioacoustics.

The song consists of repeated echemes of 10–20 ticking syllables. Echemes are repeated with intervals of 2–3 s (Fig. 92 A). The syllables are very short (<1 ms) and repeated at about 18 per second (Fig. 92 B). Within syllables, the sound is seemingly primarily produced by one moving direction of the hind legs. The frequency spectrum is quite broad, with main frequencies between 4 and 7 kHz (XC 877928, accessible at https://www.xeno-canto.org/877928).