Isophya thracica Karabag 1962

2.3. Isophya thracica Karabag 1962

(Figs 3, 34, 59, 83, 108, 134, 138, 191)

Isophya thracica Karabag: Karabag 1962 (sp.n.).

Morphological description: Karabag 1962; Harz 1969; Heller 1988. Bioacoustics: Heller 1988.

The species has unique combination of characters of the male and female tegmina (Figs 3, 34, 59). While males have outstandingly long tegmina with very short CuP similarly to the primitive state in I. straubei group, the female tegmina show advanced shortening and reticulate venation of tegmina. Hind femora lack ventral spines. CuP is weak and among the shortest in Isophya being about 1/2 of the hind edge of pronotum; CuP and CuA are widely separated. Male and female stridulatory apparatus are shown on Fig 134 (A and D). Male stridulatory row has a length of 1.78–2 mm with 58–70 teeth. Male cerci (Fig. 83, 134 C) are stout, apically strongly incurved and bear a large, showel-like tooth. The ovipositor (Fig. 108) is short (7.5–9 mm). The song (Fig. 113) consists of short isolated syllables divided into main part and an after-click.

Bioacoustics: The song was studied in specimens from Elmali Village in European Turkey. At a temperature of 17–19°С the song consisted of single syllables that rarely were mixed with groups of two syllables. Syllables were repeated at an interval of 7–15 or, when grouped, at 1.5–3 s. The syllables are composed by main part followed by additional part of a single or up to three after-clicks. The main syllable part lasted 67–86 ms (mean 76±5; n=32) and consisted of 18–25 impulses (mean 21±2; n=30) with impulse period of 3–9 ms. The first impulse has much higher amplitude than the rest in the syllable. The additional syllable part followed at 48–143 ms (mean 82±27; n=31) and was composed by one or up to three impulses; the impulse period if more than one impulse lasted 10–15 ms. The total syllable length was 124–212 ms (mean 174±23; n=31). The song properties presented by Heller (1988) were measured at over 24.5°С and in order to be comparable we preferred to give similar data in the Tabulated key (Table 1).

Distribution (Fig. 191) and phenology: Endemic for the southern part of Eastern Thrace (European Turkey). Its phenology is poorly known; early species emerging in February–April and imaginal moulting from the end of April; imagines disappear in July. Near Elmali Village the species was found within xerothermophyte scrub of Quercus pubescens and Juniperus oxycedrus but possibly inhabits a wide variety of vegetation types.

…… continued on the next page II. Northern stock or Northern species of Isophya

A large number of taxa (i.e. presently 36 species) with various morphological features and song structures occur from Northwestern Anatolia to Central and Eastern Europe reaching the Altai Mountains in the East and the Pyrenees in the West. Warchałowska-Śliwa et al. (2008) classified the taxa studied by them in four groups: I. modesta, I. pyrenaea, I. costata and I. kraussii group. Yet, outlining these is complicated due to transitional morphological characters, undescribed songs, and great genetic similarity resulting in perplexed molecular phylogeny. The group is quite diverse morpho-acoustically but the transitions may be very smooth and thus clear distinction between the groups is frequently difficult. Excluding the majority of I. modesta group, making the transition between the primitive I. straubei and I. rectipennis groups and the typical Northern stock, most taxa concerned here have the following common morphological tendencies: (1) shortened tegmina both in males and females with blunt apical parts in females; (2) moderately or strongly approximated CuP and CuA; (3) female tegmina with reticulate venation; (4) lack of typical melanism or, in some taxa, tendency of development of melanistic colouration. Re-evaluating the known taxonomic characters we generally sustain the classification by Warchałowska-Śliwa et al. (2008), yet using the possibility of further subdivision of some of these groups. The following groups are considered here: (1) I. modesta group; (2) I. costata group; (3) I. kraussii group; (4) I. pyrenaea group.