Reassessment of the genus Lophurella (Rhodomelaceae, Rhodophyta) from Australia and New Zealand reveals four cryptic species

Abstract

Cryptic diversity is common in the red algae and is often discovered when comparing specimens from distant locations or different morphotypes of species with high phenotypic plasticity. The genus Lophurella includes seven species from the cold-temperate coasts of the southern hemisphere. L. periclados is the only species reported from Australia where two morphotypes were identified in relation to levels of wave exposure. In New Zealand, three species of Lophurella have been reported – the endemic L. caespitosa (type locality Parimahu, North Island of New Zealand), L. hookeriana (type locality Cape Horn, South America) and L. periclados. We reassessed species diversity of Lophurella in Australia and New Zealand with the aim of determining (1) whether New Zealand and South American specimens of L. hookeriana actually represent a single species, and (2) if the morphotypes of L. periclados mask cryptic diversity. We studied rbcL sequences and morphological features of 36 specimens identified as L. periclados, one specimen of L. caespitosa, and five samples of L. hookeriana, three from New Zealand and two from Cape Horn. Molecular analyses revealed that L. hookeriana from New Zealand and South America are distinct species and the new species L. pauciramulosa is described from New Zealand. L. periclados is a complex involving four species and we propose three new species, L. mutabilis, L. nigra and L. tasmanica. Cryptic diversity in L. periclados did not align with the previously defined ecotypes and several species were often found at the same site. L. periclados, L. nigra and L. tasmanica can be distinguished by morphological characters. Conversely, L. mutabilis has high morphological plasticity, with characters that overlap with L. periclados and L. nigra, and can only be distinguished by DNA sequences.