Twelve of the 13 bushcricket species of the Saga genus are bisexuals and diploids,
except the parthenogenetic and tetraploid bush cricket, Saga pedo. Despite a continuous
research effort stretching through the 1900s, the taxonomic relationships of the Saga
species are still disputed. In this study, our primary aim was to reveal natural relationships
of the European Saga species and three of their Asian relatives, with special attention
to the problematic taxonomy of two subspecies: S. campbelli campbelli and S. c. gracilis.
Following a phylogenetic analysis of eight species, a comprehensive study was carried
out on the above three taxa by using acoustic and morphometric approaches in parallel.
Our phylogenetic data showed that European Saga species evolved from a monophyletic
lineage. The geographical transitional species S. cappadocica was positioned between
European and Asian lineages supporting the idea that the European Saga lineage originated
phylogeographically from the Asian clade. The above results showed better agreement
with the morphological data than with earlier ones based either on karyology or acoustic
information only. After reviewing our data, we concluded that Saga pedo has most likely
evolved from S. c. gracilis and not from S. rammei or S. ephippigera, as proposed
by earlier studies. S. c. gracilis shares the same ITS2 haplotype with S. pedo, indicating
that the latter could have evolved from populations of the former, probably through
whole genome duplication. Based on acoustic and morphometric differences, we propose
to elevate the two subspecies, S. campbelli campbelli and S. c. gracilis, to species
level status, as Saga gracilis Kis 1962, and Saga campbelli Uvarov 1921. The present
work sets the stage for future genetic and experimental investigations of Saginae
and highlights the need for additional comprehensive analysis involving more Asian
Saga species.
