Bathy- and mesopelagic annelida from the Arctic Ocean: Description of new, redescription of known and notes on some “cosmopolitan” species

Abstract

Pelagic polychaetes collected in the deep Arctic Ocean between 2011 and 2016 during three expeditions of R/V Polarstern were investigated using morphological taxonomic and molecular methods based on DNA sequences for portions of the mitochondrial 16S and nuclear 18S and 28S rDNA genes. A comparison of our results on arctic Pelagobia cf. longicirrata Greeff, 1879, (Lopadorrhynchidae) and Typhloscolex cf. muelleri Busch, 1851 (Typhloscolecidae) with the data on P. cf. longicirrata and T. cf. muelleri from the Atlantic, Antarctic and Pacific, suggests the presence of species complexes within each of them instead of cosmopolitan species. We infer the validity of Phalacrophorus borealis Reibisch, 1895 (Iospilidae), synonymized earlier by several authors with cosmopolitan P. pictus Greeff, 1879 as a subspecies. Also, we describe a new Lopadorrhynchidae genus, Bathypelagobia gen. nov. with a redescription of Pedinosoma polaris (Buzhinskaja, 2017). Finally, we describe a new Polynoidae species, Bathypolaria kondrashovi sp. nov. with some notes on the reproductive biology of the latter species.