Elbenia Stål, 1876

Gorochov, A. V., 2023, Taxonomy of the katydids (Orthoptera: Tettigoniidae) from East Asia and adjacent islands. Communication 16, Far Eastern Entomologist 485, pp. 7-28 : 8-9

Genus Elbenia Stål, 1876

NOTES. Up to now this genus contains 21 species distributed from Indochina (including South China) to the Philippines and Malay Archipelago but unknown in more eastern islands of this archipelago than Borneo and Java ( OSF). Its general appearance is rather uniform: the body coloration is greenish with a brown to blackish area on the proximal part of the both dorsal tegminal fields ( Figs 1, 2, 5–8, 11, 12 , 80, 81, 84–87, 90–91, 121, 122, 141, 142); the upper rostral tubercle is rather narrow and not long but flattened dorsally and with a distinct dorsomedian groove; the pronotum is rather high, with a short hind lobe and not deep humeral notches; the tegmina are long and rather narrow, with a simple and moderately developed stridulatory apparatus ( Figs 1–12 , 80–91, 121, 122, 139–142); the hind wings are distinctly longer than the tegmina and clearly protruding beyond their apices; the legs are thin, moderately long, with small spines (the femora are almost without spines) and two tympana on each fore tibia (the tympanal region of this tibia is almost not thickened or not widened; the inner tympanum is slit-like and almost not iflated, but outer one open, oval). However, some sexual characters are diverse: the male last abdominal tergite has a pair of distinct posterior lobes, but sometimes, it has one posteromedian lobe or lacks any lobes (belonging of such species to this genus is problematic); the female last tergite usually has a pair of smaller lobes (female is known only for a few species; Figs 60, 96, 149); the male cerci are thin and rather long, arcuate or somewhat S-shaped, with more or less acute apices; the male genital plate is elongated or with long posterior lobes curved upwards, deeply or moderately notched (sometimes slightly notched or almost without posteromedian notch); the male genitalia are completely membranous; the female genital plate is small and lobule-like, but the female last sternite is often somewhat specialized (Figs 22, 23, 95, 96, 130, 131, 148, 149); the ovipositor is rather long, comparatively low and moderately arcuate as well as with small denticles along its ventral and sometimes dorsal edges (Figs 23, 96, 130, 149).

In relation to the male abdominal copulatory structures, this genus may be divided into a few subgenera which are described below (in a subgeneric key of Elbenia s. l.). Also, it is necessary to note that some species may belong to other genera: for example, Elbenia makilingae Hebard, 1922 was described from one female ( Hebard, 1922), but its ovipositor is very dissimilar to those of all other known females of this genus (this species is here excluded from the genus studied); “ Elbenia” loliifolia (Haan, 1843) possibly belongs to Casigneta Brunner-Wattenwyl, 1878 ( Karny, 1926b; OSF); Elbenia manilensis Pictet, 1888 is insufficiently described for understanding its generic position (here this species is not included in any subgenus of Elbenia s. l); Elbenia fissa Karny, 1923 (Malay Peninsula) and Elbenia fusca Karny, 1923 (Borneo: Sarawak) are tentatively attributed to the nominotypical subgenus, because their male genital plates and male cerci are somewhat similar to those of Elbenia s. str., but their original descriptions contain the words that their male “anal segment [last tergite]” is “truncate behind” and “slightly emarginated behind”, respectively ( Karny, 1923). Moreover, Elbenia (Elbenia) bakeri (Karny, 1921) , comb. nov. previously included in the genus Furnia Stål, 1876 is here transferred to Elbenia s. str., as this species has all the male and female characters (including the ovipositor shape) according to the latter subgenus, but the type species of Furnia (judging by its holotype photograph in OSF) has the ovipositor distinctly shorter and strongly curved upwards.

For understanding these subgenera, the following preliminary hypothesis on the evolution of copulatory structures in this genus is proposed: (1) the general ancestor had the male last tergite with one posterior lobe, the male cerci arcuate (i.e. with their apical parts curved medially), and the male genital plate elongated but not long and not curved upwards as well as with a very small apical notch and without a pair of inner subapical denticles; (2) in one branch of its descendants, the male cerci acquired more or less S-shaped bend with their apical parts curved laterally (such cerci have a very dissimilar method of fixing female during copulation; Javapteron subgen. n.), and later the long posterior lobes of the male genital plate additionally developed ( Tamdaopteron Gor. ); (3) in another branch, these cerci retained arcuate, but the male genital plate acquired a pair of inner subapical denticles ( Aequapteron subgen. n.) or began to acquire the long posterior lobes (parallelism to the previous branch; Elbenia s. str.); (4) in the third branch, only the long lobes of the male genital plate developed (also parallelism to the both previous branches), but all the other characters retained as in the general ancestor ( Hemielbenia subgen. n.).

Figures

Figs 1–12. Elbenia, male: 1–3 – E. (Tamdaopteron) ryabovi sp. n.; 4–6 – E. (T.) daedala sp. n.; 7–9 – E. (T.) subrecta sp. n.; 10–12 – E. (Elbenia) carinata sp. n. Stridulatory apparatus of left (1, 5, 7, 11) and right (2, 6, 8, 12) dorsal tegminal fields from above; teeth of stridulatory vein of left tegmen from below (3, 4, 9, 10).