Evolutionary relationships among several species from the genus Cricotopus (Diptera: Chironomidae): What about Turkish representatives of this genus?

Abstract

The genus Cricotopus (Diptera: Chironomidae) has a worldwide distribution and possesses a wide variation in ecology and habitat preference across its distribution. Identification of Cricotopus species and distinguishing them from the species of closely related genera (i.e. Orthocladius and Paratrichocladius) are generally difficult. This study aimed to investigate the evolutionary history of several Cricotopus species, with the main focus on C. bicinctus, C. flavocinctus, C. triannulatus, C. patens, C. intersectus, C. laricomalis, C. ornatus, C. reversus, and C. sylvestris from Turkey, using the mitochondrial cytochrome c oxidase subunit I (COI) gene. Molecular classifications of Turkish Cricotopus species were full compatible with the morphological species identity, suggesting the adequacy and practicability of existing larval keys for identifying these specimens o species level. The sampled Turkish Cricotopus species with two or more representatives were found to produce monophyletic groups. Diversification time estimates showed that the diversification of Cricotopus was initiated in the late Cretaceous. Additionally, these estimates suggested a distinct continental structuring in the evolution of some species and a possible origination of the sampled Turkish representatives of this genus from North European representatives. Based on the results of this study, the COI gene is concluded to be useful both for species identification in the genus Cricotopus and for estimating their evolutionary relationships. This study provides valuable information on the evolutionary relationships among Cricotopus species. However, to obtain more accurate and/or persuasive results, an intensive and targeted sampling from more locations and the inclusion of more sequence data from not only the mitochondrial COI gene but also additional nuclear and/or mitochondrial markers are highly recommended for further studies.