Arantia (Euarantia) congensis Griffini, 1908

Heller, Klaus-Gerhard, Hemp, Claudia, Liu, Chunxiang & Volleth, Marianne, 2014, Taxonomic, bioacoustic and faunistic data on a collection of Tettigonioidea from Eastern Congo (Insecta: Orthoptera), Zootaxa 3785 (3), pp. 343-376 : 358-360

Arantia (Euarantia) congensis Griffini, 1908

CH 4943, CH 4992 f♀

The species was described by Griffini (1908c; type locality Congo, Bus(s)ira: probably 0º50’S, 19º56’E) as a subspecies of A. melanota Sjöstedt, 1901 (type locality Cameroon, (M)Bonge, probably 4º32’N, 9º06’E) and elevated to species rank by Otte (1997) without comment, possibly because the genital structures have been described being different. Our specimen ( Fig. 1 D) differs in this character clearly from A. melanota , but agrees quite well with the description of the cercal structure of A. congensis (see Fig. 10 A, B for our specimen). All other Arantia (Euarantia) species with known males can be definitively excluded since their cercal morphology is different.

On the second abdominal segment, the male carries a large gland-like structure, a smaller one also on the first. At the posterior end of many tergites (2nd -8th) there is a small spine.

The females are characterized by the unusually large, broad-based spines (especially the last two) on both edges of the underside of the hind femur ( Fig. 10 C). A. (E.) fasciata has some spines only on the internal edge ( Fig. 10 G; Brunner von Wattenwyl 1891, as spinulosa and atrolineata), A. marmorata has only one large spine on both sides ( Karsch 1889) on the hind femur ( Fig. 10 F). Even the spines (on both edges) of A. melanota ( Fig. 10 E) and the male of A. congensis , which are relatively large, are clearly smaller ( Fig. 10 D). All other species have only much smaller spines according to the photos in OSF or the descriptions. In addition, male and females differ in colouration of the caudal edge of pronotum (see Fig 1 D, E) and texture of the tegmina. From the genetic similarity, however, we are convinced that the three specimens belong to one species, and give a detailed description of the hitherto unknown female because of these unusually large differences.

Colour. See Fig. 1 E.

Head. Fastigium verticis ends in a narrow, finger-like process, about a quarter as wide as scapus, sulcate before the process, met from below by conical, weakly sulcate fastigium frontis, leaving a gap between ends. Antennal sockets strongly margined (considered as typical for Pseudophyllinae ; Rentz 1979). Scapus large, its distal half slightly inflated. Eyes circular, the diameter at base smaller than further distal, striped.

Thorax. Surface of pronotum smooth, without carinae. Posterior part of disc red ( Fig. 11 C). Fore coxa without spine. At the lower side fore femora with 3 to 4 spines at inner edge, mid femora unarmed, hind femora with 6-7 spines at both edges each. All tibiae with few to many spines or spinules on both edges above and below. Hind tibiae distinctly curved. Tibial ears in the fore legs anteriorly conchate, posteriorly open, leg dark coloured in this region. Auditory spiracle very large, but entrance for the most part covered by paranotum.

Wings. Tegmina broad (see Table 3 ), broadly pointed at tip, with black markings at the very base ( Fig. 11 A). Upper side of right tegmen with nine veins carrying stridulatory teeth. Alae slightly longer than fore wings. Colour green, with some brown-white markings at vein connections. Venation see Fig. 11 A, B.

Abdomen. Subgenital plate comparatively short. Last tergite dorso-posteriorly with a large soft protuberance, covered with hairs, only the most posterior part smooth (not well preserved in the dried specimen). Ovipositor short (4 mm), near the tip at edges and on the surface with spines.

Measurements see Table 3 .

Behaviour. During our stay we have taken two photographs which may represent subadult nymphs of this species recognisable by the large spines and the curved hind tibiae. On both images the animals sit with the antennae placed below the body ( Fig. 1 F). This behaviour was known only from some South East Asian Holochlorini ( Stictophaula spp. Ingrisch 1994; own unpublished observations in other Stictophaula species and Ancylecha fenestrata ) and recently also from some East African phaneropterine (genera Gonatoxia , Lunidia , Melidia , Oxyecous , Terpnistria ; CH, own unpublished observations).

Figures

FIGURE 1. Habitus. A— Horatosphaga leggei, B— Pardalota asymmetrica, C— Pardalota asymmetrica, ♀ nymph, D— Arantia congensis ♂ CH 4991, E— Arantia congensis ♀ CH 4943, F— Arantia congensis ♀ nymph, G— Zeuneria biramosa, H—? Tetraconcha sp. ♀ (A, F photos Alois Liegl).

FIGURE 10. Characteristics of Arantia (Euarantia) species. A, B—Cerci of Arantia congensis CH 4991, A lateral, B dorsal view, scale 1 mm, C-G Hind femora of C— A. congensis ♀ (CH 4992), D— A. congensis ♂ (CH 4991), E— A. melanota (OSF, source Sweden, Stockholm, Naturhistoriska Riksmuseet), F— A. marmorata (OSF, source Poland, Warszawa, Polish Academy of Science, Museum of the Institute of Zoology), G— A. fasciata (Tanzania, Mt. Kilimanjaro).

FIGURE 11. Arantia (Euarantia) congensis A-C female (CH 4992). A—Dorsal view; B—Lateral view; C—Pronotum and base of the wings, dorsal view.