Tmethis Fieber, 1853

Massa, Bruno, 2013, Pamphagidae (Orthoptera: Caelifera) of North Africa: key to genera and the annotated check-list of species, Zootaxa 3700 (3), pp. 435-475 : 437

Tmethis Fieber, 1853 (type-species: Gryllus cisti Fabricius)

Fieber (1853) did not explain the origin of the name Tmethis ; thank to my Greek colleague Haralabos Tsolakis, it was possible to trace a link with the verb "temno" (τέΜνω), which means "to cut", possibly referred to the particular shape of pronotum, with a distinct sulcus between prozona and metazona. I consider that Tmethis is of masculine gender, and consequently I will agree taxa with it. In his excellent revision of all Palaearctic Thrinchinae , Uvarov (1943) pointed out the high variability of many species, mainly belonging to genera Tmethis and Asiotmethis Uvarov , that may have wrinkled or smooth integuments; sculpturing of exposed parts (mainly pronotum) may be devoid of the usual tubercles and keel. Thus, taxa belonging to the genus Tmethis are much variable, not only in their general colour and in the length of wings, but also in their integuments and body structure, which may be more or less stout or slender. Some specimens appear squat and broad ( Figs. 73, 75 ). In addition, the colour of hind tibiae varies from red to yellow and to purple or bluish-violet; it seems that this variation characterizes single populations. The arrangement of species within the genus was much unclear, in particular the separation of T. cisti from T. pulchripennis . Reading Chopard (1943) it is evident that many populations of T. pulchripennis were actually T. cisti (e.g., those living on Djerba and Kerkenna Is.). The first author who defined characters to identify species was Uvarov (1943); he recognized T. maroccanus from T. cisti and T. pulchripennis by the shape of the metazona of pronotum, which is broadly parabolic with convex margins in the former and triangular, with the sides straight or somewhat incurved in the other two species. Additionally, he identified T. cisti and T. pulchripennis by the shape of their male epiphallus, and by small differences on the lower valve of the ovipositor and length of spurs of hind tibiae. Thus, records of species in North African countries may be considered reliable only if criteria used by Uvarov (1943) were followed. However, La Greca (1969) considered much variable the shape of lower valve of the ovipositor (according to Uvarov (1943) in T. pulchripennis with a distinct shoulder, which appears as a tooth in lateral view, while in T. cisti it appears without a projection, not dentate), and identified some T. pulchripennis from Libya, following criteria of Chopard (1943), based on the pronotum shape, that during this study resulted to be a very variable character. Tegmina length is also a variable character, as supposed by Jannone (1938). Eight subspecies or varieties have been described for T. cisti , three for T. pulchripennis and three for T. maroccanus , in some cases overlapping. I will examine each of them to establish if their taxonomic status is justified.

Figures

FIGURES 60 – 75. 60 – 71. Tegmina of Tuarega insignis from different North African localities to show the variability of vein branches, including topotype locality of T. ouarzazatensis (63, 65) and types of T. parisi (68 – 69) and T. sahara (70 – 71). 72. Lateral view of T. insignis. 73 – 75. Tmethis maroccanus and T. cisti from above to show variability of body stoutness.