The genus Arthrocardia (Corallinales, Rhodophyta) in New Zealand: Description of three new species

SUMMARY Three new species of the coralline algal genus Arthrocardia (Corallinophycidae, Rhodophyta) are described from New Zealand: A. meridionalis , A. perplexa , and A. robusta . These species are difficult to distinguish based on morphoanatomical characters alone and require molecular sequence data for reliable identification. The northern A. meridionalis and southern A. robusta have non‐overlapping geographic distributions, while each of these species overlaps with A. perplexa in central New Zealand. Based on sequence data, A. meridionalis is conspecific with a South African species of Arthrocardia designated as “sp. 1” in an earlier study. Additionally, the two species previously reported from New Zealand, A. corymbosa (based on South African type material) and A. wardii (from South Australia), are considered not to be present in New Zealand.