Neopolyporolithon loculosum is a junior synonym of N. arcticum comb. nov. (Hapalidiales, Rhodophyta), based on sequencing type material

One of the earliest described non-geniculate coralline algae from the Arctic is Kjellman's 1877 Lithophyllum arcticum. It has been classified successively in Lithothamnion and Mesophyllum and currently is in Leptophytum, all based on morpho-anatomy. A 263 base-pair (bp) fragment of the rbcL gene was sequenced from the lectotype specimen, and it is an exact match to Neopolyporolithon loculosum. Because Lithothamnion loculosum, basionym of N. loculosum, dates only from 1889, the priority of publication necessitates Neopolyporolithon arcticum comb. nov. for this species. The biogeographic provinces and distribution of this alga are expanded from the boreal and subarctic North Pacific to the western Russian Arctic. Given the rapid warming of the Arctic, DNA sequence data are urgently needed for coralline algae from all arctic and subarctic marine regions to document their current distributions in order to assess future changes.