Thyridorhoptrum carbonarium (Redtenbacher, 1891) Redtenbacher, 1891

Massa, Bruno, 2015, Taxonomy and distribution of some katydids (OrthopteraTettigoniidae) from tropical Africa, ZooKeys 524, pp. 17-44 : 19

Taxon classification Animalia Orthoptera Tettigoniidae

Thyridorhoptrum carbonarium (Redtenbacher, 1891) comb. n. Figs 1-7, 8-12

Material examined.

Ivory Coast, Man, Mt. Tonkoui (1200 m) 7°26'58.46"N, 7°39'01.14"W 1-2.VII.2014 (UV), P. Moretto (1♂, 1♀); Ivory Coast, Man, Mt. Tonkoui (1200 m) 28.VI-1.VII.2014 (UV), P. Moretto (5♂, 4♀); Ivory Coast, Man, Mt. Tonkoui (1200 m) 24-27.XI.2014 (UV), P. Moretto (2♂, 3♀); Ivory Coast, Korhogo Village (347 m) 9°25'07.02"N, 5°36'59.41"W 13-15.VII.2014 (UV), P. Moretto (1♂) (BMCP).

Previous records.

Redtenbacher (1891) described this species from Accra (Ghana). Chopard (1954) reported it as Conocephalus from Guinea, Ragge (1967) listed it again as Conocephalus from Democratic Republic of Congo, and Naskrecki (2008, 2009) from Ghana.

Redescription.

When Redtenbacher (1891) described this species, he highlighted that two spines are present on the prosternum. Thus, it cannot be ascribed to the subgenus Conocephalus Thunberg, 1815, that lacks these spines. However, characters of male and female are more matching those of the genus Thyridorhoptrum than those of Anisoptera Latreille, 1829, to which the species has been ascribed by Kirby (1906). The characters are: Fastigium of vertex very narrow and raised between antennae (Fig. 3). Antennae twice longer than body. Eyes round (Figs 8, 10, 12). Fore coxae armed with a long spine, fore and mid femora unarmed, hind femora with 3 spines on outer lower margin. 1 small spine on the outer genicular lobe of fore femora and on inner and outer hind femora. Fore and mid tibiae with 4-5 spines on lower margins + 1 spur on each side, dorsal margins unarmed. Tympanic auricles closed. Hind tibiae with 8-10 spines on both lower margins + 2 spurs on each side; upper margins with many spines + 1 spur on each side. Sternum armed with two spines. Tegmina as long as abdomen or little shorter, clearly inflated, hind wings nearly rudimentary, as long as tegmina but very narrow. The stridulatory area of the left tegmen is accentuated by a swelling of the rib, which gives an undulating appearance when viewed along the lateral plane of the wing (Figs 1, 10). Stridulatory file of left tegmen as in Fig. 9; row of teeth not much curved, differentiated into very dense teeth at the dorsal and proximal ends and large and spaced teeth in the central section. The mirror of right tegmen is slightly rounded (Fig. 11). Cerci finely pointed, with two inner spines, the first shorter than the second, both are smooth (Fig. 6). Sub-genital plate concave with small styli (Fig. 7). Titillators, previously undescribed, are small and round, with a very wrinkled surface (Fig. 5). Female pronotum not raised, with metazona matt and roughly punctate (Fig. 12), micropterous, with very short tegmina, narrow hind wings, just exceeding tegmina (Figs 2, 12). Ovipositor gently up-curved (Fig. 4), sub-genital plate triangular with straight margin. Cerci conical.

Colour.

Brown with green parts, with a clear darkish stripe on head and pronotum, continuing on fore wings. Frons green, hind legs with darkish markings in the distal parts of femora and basal parts of tibiae, in some specimens darkish outer face of hind femora (Figs 1, 2).

Measurements.

See Table 1. Thyridorhoptrum carbonarium is a small species with very short wings (mainly in the females) and short ovipositor.

Diagnosis.

No brachypterous species of Thyridorhoptrum are known. Both Thyridorhoptrum senegalense and Thyridorhoptrum baileyi are long-winged. The mirror of male right tegmen of Thyridorhoptrum carbonarium is similar to that of the small mirror form of Thyridorhoptrum senegalense , while in Thyridorhoptrum baileyi is more triangular. The stridulatory files are differently shaped in the other two species (see Pitkin 1977). The first inner spine of cerci in Thyridorhoptrum senegalense and Thyridorhoptrum baileyi has a serrated apex, while it is smooth in Thyridorhoptrum carbonarium . The ovipositor of Thyridorhoptrum carbonarium is gently up-curved, while in the other two species it is quite strongly up-curved.

Habitat.

According to Chopard (1954), this species was collected in Guinea in forest habitats. Mt. Tonkoui is a forested mountain of Ivory Coast, with an average elevation of ca. 1,000 m a.s.l. It is covered by a tropical Moist Forest with evergreen broadleaved species. Nevertheless, Thyridorhoptrum carbonarium is not strictly linked to forest habitats, because it has also been collected at light in the village of Korhogo (347 m). It seems that the main geographical feature is an average annual rainfall of ca. 1,200 mm, with the rainiest months being May to October, when adults of Thyridorhoptrum carbonarium are active.