Genetic connectivity between trans-oceanic populations of Capreolia implexa (Gelidiales, Rhodophyta) in cool temperate waters of Australasia and Chile

• This is the first report of Capreolia implexa outside of Australasian waters.
• Analysis of cox1 revealed two genealogical groups within C. implexa.
• The extremely low genetic diversity in C. implexa in Chile suggests a result of colonization after dispersal by rafting from Stewart Island, New Zealand.
• C. implexa is environmentally tolerant and wide-spread in Chile.

Capreolia is a monospecific genus of gelidioid red algae and has been considered to be endemic to Australasia. This is the first report on the occurrence of Capreolia implexa outside of Australasian waters, based on investigations of fresh collections in southern Chile as well as Australia and New Zealand. Thalli are prostrate and form entangled turfs, growing on high intertidal rocks at three locations in Chile. Analyses of rbcL and cox1 revealed that C. implexa was of Australasian origin and also distinct from its relatives. Analyses of 1356 bp of cox1 revealed cryptic diversity, consisting of two genealogical groups within C. implexa; one present in Australia and New Zealand, and the other in Chile and Stewart Island, New Zealand. The extremely low genetic diversity found in C. implexa in Chile and the absence of shared haplotypes between Chile and Australasia suggest genetic bottleneck possibly as a result of colonization after dispersal by rafting from Stewart Island, New Zealand to Chile.