Bioacoustics of Arantia (Euarantia) excelsior

Measurements . Body length: 33.8±1.3; pronotum length: 8.3±0.3; pronotum height: 9.3±0.2; hind femur: 28.4±1.3; hind tibiae: 33.6±0.4; tegmina: 57.5±1.4 ( ♀ holotype : 68.4); tegmina width: 15–21; tegmina length/ width: 2.7–3.2 ( ♀ holotype : 3.2); tegmina width/pronotum length: 1.9–2.1. Characters . Karsch (1896) described A . excelsior on a single male from Sierra Leone (Fig. 34). A few years later he described A . mammisignum on a single female from Cameroon (Fig. 37). The most conspicuous characters of A . mammisignum are the two shiny white patches on the posterior part of the pronotum, and black markings on the fore margin of the tegmina. Obviously because of the conspicuous two white patches on the posterior pronotum Karsch did not realize that the newly described female was conspecific with A . excelsior . However, also the male shows this conspicuous character of white patches on the posterior margin of the pronotum, as well as black markings on the tegmina ( Figs 39–40 ). Now more specimens became available for study and it became obvious that A . mammisignum is conspecific with A . excelsior . Collections of MNCN hold a specimen from southern Cameroon (Dibongo) identified as A . tigrina , which is almost identical with the female of A . mammisignum including the colour pattern of the two large white patches on the posterior margin of the pronotum. The male holotype of A . tigrina (Fig. 36) has the same genitalic morphology as A . excelsior : the male cerci are stout at their base tapering to the apex, are sinuous midway and end in a dark coloured club (compare Figs 96, 97, 98 ). The male subgenital plate is very distinctive being elongate, almost rectangular and very narrow without styli but blunt short processes. Also the costal area of the tegmina has brown to black markings both in the A . excelsior and the A . tigrina types . In specimens studied the metazona of the pronotum is often brown with a whitish area at the posterior margin. Two large white patches may be present on the posterior pronotum ( holotype A . mammisignum , female paratype A . tigrina ), may cover the whole posterior down-curved part of the pronotum ( holotype A . tigrina ) or may be restricted to the immediate margin ( holotype A . excelsior ). Typical is also a strong deflection of the pronotal disc in the area of the metazona ( Fig. 39 ). The face of the holotype in A . excelsior is reddish brown while it is ivory white in A . tigrina ; the face of the female of A . tigrina in MNCN is uniformly brown. Therefore, colour variation is apparent in this species as has also observed e.g. in specimens of A . fasciata from East Africa, as well as differences in body size. Some specimens of A . excelsior have blackish stripes on the legs (including the tympana of the fore tibia). Thus, both A . tigrina and A . mammisignum are here synonymized with A . excelsior . The stridulatory file of A . excelsior is short and broad and consists of ca. 65 more evenly spaced teeth ( Fig. 64 ). Further, some specimens (from Ivory Coast ) have both inner and outer tympana closed on the fore tibia. Affinities . A . excelsior is closely related to A . rectifolia and A . regina having a similar habitus of broad leaflike wings and similar male genitalia. A . rectifolia has tegmina less broad than A . excelsior and A . regina . In addition, in A . regina the male cerci are more slender and the club at the tips of the cerci is not as large as in A . excelsior . The female ovipositor is smaller in A . rectifolia . Also A . rectifolia lacks the brown-black patches at the anterior margin of the tegmina which seem typical for A . excelsior (Fig. 34). Another striking difference is seen on the metazona of the pronotum. In A . excelsior a conspicuous deflection is present while in A . rectifolia and in A . regina the posterior part of the metazona is only shallowly bent.