Re-examination of the taxonomic status of Anopheles hyrcanus and Anopheles pseudopictus using a multilocus genetic approach

Authors: MIAOULIS, MICHAIL - European Biological Control Laboratory (EBCL); GIANTSIS, I - American Farm School; SCHAFFNER, F - University Of Zurich; CHASKOPOULOU, ALEXANDRA - European Biological Control Laboratory (EBCL)

Submitted to: Journal of Vector Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/14/2018
Publication Date: 6/1/2018
Citation: Miaoulis, M., Giantsis, I., Schaffner, F., Chaskopoulou, A. 2018. Re-examination of the taxonomic status of Anopheles hyrcanus and Anopheles pseudopictus using a multilocus genetic approach. Journal of Vector Ecology. 43(1):179-183. doi:10.1111/jvec.12297.
DOI: https://doi.org/10.1111/jvec.12297

Interpretive Summary: Amongst vector-borne diseases, malaria is considered to cause the largest burden, with a global estimation of more than 200 million cases and 400,000 deaths per year. Mosquitoes of the genus Anopheles are the vectors of the Plasmodium parasites, including the species of the Anopheles hyrcanus group. Two members of the Hyrcanus group have been recorded in Central and Southern Europe, namely An. hyrcanus and An. pseudopictus. The taxonomy of these 2 taxa remains controversial since recent studies and identification keys refer to these taxa either as separate or the same species. This study provides solid evidence that these two taxa constitute the same species.

Technical Abstract: Mosquitoes-members of the Anopheles hyrcanus group are vectors of malaria pathogens in the areas they inhabit. While the majority of the Hyrcanus group members are distributed in the Eastern Palearctic and Oriental regions where they compose great species diversity, only 2 members have been recorded in Central and Southern Europe, namely An. hyrcanus and An. pseudopictus. The only morphological difference, between the taxa An. hyrcanus and An. pseudopictus, is a chromatic variation in the tarsomere IV of the hind leg, while there also exists an intermediate form that has white basal and apical bands separated by a black median area. The main objective of the present study was to evaluate the genetic similarity of the two taxa by examining their genetic relationships using a multilocus mitochondrial (COI and ND4 genes) and nuclear (28S domain-2) approach. In total 40 adult specimens of the Hyrcanus group were included in the molecular analysis: 24 specimens from Greece, 8 specimens from France and 8 specimens from the Czech Republic. The final alignments comprised 577 base pairs (bp), 625 bp and 622 bp, for the 28S, the COI and the ND4 genes, respectively. Overall mean genetic distance among newly defined haplotypes ranged from 0 to 0.004 indicating generally very low levels of genetic variability. One unique haplotype was derived from all Greek, Czech and French samples in the 28S gene, for both An. hycanus and An. pseudopictus, as well as the intermediate morphological type. This haplotype was also identical with a homologous sequence from Austria obtained from Genbank, indicating complete absence of genetic variation among European samples in the 28S gene. The only case of genetic variation in 28S gene was observed between European specimens and a haplotype from China (pairwise genetic distance 0.006), providing evidence for greater differentiation by distance than inter-taxa. For both mitochondrial markers inter-taxa genetic differentiation was lower than genetic differentiation between geographically distant specimens, as was found for the nuclear 28S marker. Thus, based on (a) the present analyses of haplotypes from Central and Southern Europe, Eastern Mediterranean and Asia, (b) the lack of solid evidence for treating these taxa as different species and (c) previous findings investigating other molecular markers we conclude that An. hyrcanus & An. pseudopictus should be appointed back in their former status as synonym species.