Sphingonotus (Sphingonotus) insularis ( Popov, 1957 )

Sphingonotus (Sphingonotus) insularis ( Popov, 1957) View in CoL

Figs 94 View Figure 94 , 95 View Figure 95 , 96 View Figure 96 , 97 View Figure 97 , 98 View Figure 98 , 99 View Figure 99

References for Socotra.

Popov (in Uvarov and Popov (1957)): 377–378, figs 24–26 [as Wernerella insularis ]; Johnsen 1985: 156, 166 [as W. insularis ]; Wranik 2003: 323–324, plates 152, 157 [as W. insularis ]; Massa 2009: 57–59, figs 17–19.

Diagnostic notes.

Sphingonotus (Sphingonotus) insularis is easy to distinguish from other members of the genus in the Archipelago by the strongly undulated margins of the pronotum, the sudden notch in the dorsal carina of the hind femur close to the knee, the very large meso- and metasternal interspaces, the microscopic pearls on the tegmen and the stout appearance of the animal (Figs 94 View Figure 94 , 95 View Figure 95 ) ( Massa 2009). The hind wings are basally light blue and have a short, often incomplete band not reaching the hind margin and covering only the first anal veins. This band may sometimes only consist of separate dark spots (Fig. 95 View Figure 95 ). The key in Johnsen (1985) separates S. insularis from other species formerly attributed to Wernerella by the deep blue supra-anal plate in the males.

Taxonomic notes.

Popov (in Uvarov and Popov (1957)) attributed Sphingonotus (S.) insularis (Fig. 95 View Figure 95 ) to the genus Wernerella Karny, 1907 , known from the Canary Islands and the Moroccan coast and considered it sister to Sphingonotus asperus (Brullé, 1840) . Hochkirch and Husemann (2008) synonymised Wernerella with Sphingonotus Fieber, 1852 : genetic analyses suggested that Wernerella is polyphyletic, comprising ancient lineages and very young species, while the characters used to identify Wernerella are variable. Hence, the authors synonymised Wernerella with Sphingonotus .

This species and some former African Wernerella species have very different characteristics from all other Sphingonotus species, as listed by Massa (2009). The notch in the dorsal carina of the hind femur is an important characteristic of Oedipoda Latreille, 1829 (in Oedipodini Walker (1871 )) . However, the head rising above the pronotum (although not visible in Fig. 95 View Figure 95 because of the angle) is a character for Sphingonotus (in Sphingonotini Johnston (1956 )) , as does the low median carina of the pronotum that is not raised as in Oedipoda . Based on the above-mentioned unique as well as intermediate characteristics between Sphingonotus and Oedipoda , the erection of a new genus for Sphingonotus insularis and some other species formerly included in Wernerella , such as S. somalicus ( Johnsen, 1985) , is suggested.

Distribution and occurrence.

The species occurs on Socotra and Samha Is. and is endemic to the Socotra Archipelago. It is widespread and common from the plains to the higher limestone plateaus. It is absent from the higher regions in the Hagher (Fig. 96 View Figure 96 ).

Habitat and biology.

Sphingonotus insularis , as a geophilous species, can be found on all kinds of dry and bare, gravelly soils from 0–900 m a. s. l. in sparse dwarf shrubland, low Croton - Jatropha shrubland, high shrubland with succulents, Frankincense and Dracaena woodland and forest and submontane shrubland and grassland. Records are from all months.

Bioacoustics.

In the available recordings, two elements can be recognised, which possibly represent both courtship and rivalry. The first element exists of repeated echemes of 3 (2–5) loosely grouped syllables (Fig. 98 View Figure 98 ). Syllables last about 18–20 ms and the syllable repetition rate within these echemes is about six per second. A clear up and downstroke within a syllable is visible in the oscillogram. The first element has a peak frequency of 3–4 kHz.

The second element is formed by an echeme with 13–21 syllables (Fig. 99 View Figure 99 ). The syllable duration is about 4 ms and syllables are repeated at the rate of about five per second. This echeme has a broader frequency spectrum and seems to be produced by wing flapping, but the latter needs to be confirmed. Massa (2009) observed specimens producing a sound before taking off. This may refer to the latter sound element.