Karyotype and COI gene sequence of Chironomus heteropilicornis Wülker, 1996 (Diptera, Chironomidae) from the Gydan Peninsula, Russia

The karyotype features and gene COI sequence of Chironomus heteropilicornis Wülker, 1996 from the Gydan Peninsula are presented for the first time. Nine banding sequences were determined, eight of them hpiA2, hpiB1, hpiC1, hpiC2, hpiD1, hpiE1, hpiF3 and hpiG1 were previously known from European, Georgian (South Caucasus) and Siberian populations. One new banding sequence for Ch. heteropilicornis, hpiB2, was found. The hpiA2 banding sequence was found in all individuals, and this is its second finding after the Georgian population (Karmokov 2019). The hpiF3 banding sequence was found only in the homozygous state. Additional B-chromosomes are absent. The genetic distances (K2P) between Ch. heteropilicornis COI gene sequence from Gydan Peninsula and Norway are 1.1­–1.3%, and Georgia – 1.8%, much lower than the commonly accepted threshold of 3% for species of genus Chironomus Meigen, 1803. The phylogenetic tree for COI gene sequences estimated by Bayesian inference showed geographically determined clusters of Norway and Gydan and a separate lineage of the Georgian population of Ch. heteropilicornis. The analysis of karyotype and COI gene sequences shows that the population of Ch. heteropilicornis from the Gydan Peninsula has an intermediate position within the Ch. pilicornis group between Georgian, Yakutian and Norwegian populations. The position of Ch. pilicornis Fabricius, 1787 from Canada and Greenland on the phylogenetic tree is discussed.