Ectatoderus guichardi Gorochov, 1993

Ectatoderus guichardi Gorochov, 1993

Figs 152 View Figure 152 , 153 View Figure 153 , 154 View Figure 154 , 155 View Figure 155 , 156 View Figure 156

References for Socotra.

Gorochov 1993: 92–93; Wranik 2003: 316, plates 146, 149 [partim].

Diagnostic notes.

Characteristic of the genus Ectatoderus is the prolonged, caudally wide and broadly rounded pronotum that completely covers the tegmina. The scape is relatively wide and the ratio of inter-antennal space (along the epistomal suture) / scape width is relatively small.

Diagnostic for E. guichardi is a protruding and bulbous clypeus, a short and relatively flat vertex and a somewhat triangular-shaped head, viewed from above (Figs 152 View Figure 152 – 154 View Figure 154 ). The ratio of inter-antennal space / scape width in Ectatoderus guichardi is around 1.66 in males and females (Table 7 View Table 7 ). The head and pronotum are light to dark reddish-brown and the abdomen is dark brown. Legs and cerci are yellowish; the hind legs are darker near the joints (Figs 152 View Figure 152 , 153 View Figure 153 ). Cerci in females almost reach the apex of the ovipositor. The male specimen collected in 2009 at Begobig is much smaller than the holotype; the female is comparable in size to the female paratypes (Table 7 View Table 7 ).

Besides E. guichardi , two unidentified species of Ectatoderus Guérin-Méneville, 1847 occur on Socotra. Possibly, they belong to yet undescribed species. We refer to these here as Ectatoderus sp. 2 and Ectatoderus sp. 3 . They are treated concisely here and in the two following species accounts.

Proper identifications and species descriptions need additional collections and material from which the song can be linked to the specimen. Specimens collected in 2010 are at MNHN, Paris and could not be analysed.

Ectatoderus sp. 2 has a less protruding, not bulbous clypeus, a longer vertex and a more rounded head with less protruding eyes (Figs 154 C View Figure 154 , 158 View Figure 158 ). The inter-antennal space / scape width ratio in Ectatoderus sp. 2 is 1.9. The brownish colours in Ectatoderus sp 2 . lack reddish tones (Figs 154 View Figure 154 , 158 View Figure 158 ). Songs of E. guichardi and E. sp 2. also differ significantly (see Bioacoustics).

Ectatoderus sp. 3 (Fig. 159 View Figure 159 ) has an even higher inter-antennal space / scape width ratio of 3.1 (based on photographs) because of a very wide vertex (wider than in Ectatoderus sp. 2 and much wider than in E. guichardi ). The body and legs are dark greyish with light markings. The pronotum is very broad with convex sides (Fig. 159 View Figure 159 ).

Taxonomic notes.

Gorochov (1993) described Ectatoderus guichardi , based on material collected by Guichard in 1967 (Fig. 153 View Figure 153 ). Guichard (1967) did not mention collecting this tiny cricket species in his diary.

Distribution and occurrence.

E. guichardi is endemic to Socotra. It is known from the Hagher, Diksam, Momi and Hamadera and is locally common, for example, at Adho Dimello, where large numbers were heard singing at night in 2010 (Fig. 155 View Figure 155 ).

For remarks on Guichard’s collecting site on Mt. Shihali on 20 April 1967, see the species account of Dioscoridus depressus .

Habitat and biology.

In 2010, we found males singing at night in various shrubs. A specimen collected in 2012 at Momi was sifted out of sediment, indicating a hidden life during the day. Records of E. guichardi are from 350–1100 m a. s. l.

Bioacoustics.

E. guichardi calls after sunset. Its song consists of a series of 2–3 echemes with a fairly constant pattern. The first echeme consists of 10–17 syllables and lasts 600–1000 ms. This echeme may be missing in a series, contrary to the second and third echeme. The second echeme is short and consists of only two syllables; the third echeme has four syllables. Syllable duration is 30–35 ms; syllable repetition rate is 15–18 / s. The carrier frequency of the song is between 4.5 and 5.6 kHz and has some harmonics at higher frequencies (Fig. 156 View Figure 156 ; XC 897108, accessible at https://xeno-canto.org/897108). Higher carrier frequencies and higher syllable repetition rates occur at higher temperatures in the lowland (e. g. RecRF 10097) compared to lower temperatures in the mountains (e. g. RecRF 10151 and 153).