Chorthippus brunneus subgroup (Orthoptera, Gomphocerinae) in Anatolia with description of two new species: data suggest an Anatolian origin for the lineage

The Chorthippus biguttulus group distributed in the west Palaearctic, while intensively examined in Europe, is poorly known in the glacial refugia such as Anatolia. This produces constraints in making accurate statements about evolution and the biogeography of the group. The C. brunneus subgroup of this lineage is examined using large amounts of morphological and song data from Anatolia (Asian Turkey) and representatives from Europe. Song and morphology in combination suggested three species to be found in Anatolia. The first is C. bornhalmi Harz which is also known from south-east Europe. The other two are new species: Chorthippus antecessor sp. n. and Chorthippus relicticus sp. n.. Morphologically, C. antecessor sp. n. is the most aberrant species of the C. brunneus subgroup, but is similar to C. bornhalmi in song. The specific song and morphology (the aberrant number of stridulatory pegs) define C. relicticus as a new species and both also indicate that it is closely related to C. brunneus and C. jacobsi. A song and morphology based phyloylogenetic assumption for C. brunneus subgroup suggests C. antecessor, C. bornhalmi and C. miramae to constitute one clade and C. brunneus, C. jacobsi and C. relicticus another. The scenario suggested for their evolution assume the following steps: (i) divergence of C. bornhalmi from a C. antecessor like ancestor, (ii) derivation of an ancestral population (which later give rise to C. brunneus + C. jacobsi + C. relicticus) from a C. bornhalmi like ancestor, and (iii) later fragmentation of this ancestral population to result in the present three species (C. brunneus + C. jacobsi + C. relicticus). All of these events seem to be correlated with the climatic cycles during Pleistocene. The conclusion is that the two new species are range-restricted, vulnerable species as is the case for many other taxa present in the Mediterranean Taurus biodiversity hotspot.