Corallina Linnaeus

Macagnan, Leonardo B., Venturin, Claudia S., Azevedo, Marina L., Harvey, Adela & Gurgel, C. Frederico D., 2023, Molecular systematics of Jania species (Corallinales, Rhodophyta) from south-eastern Australia based on cox 1 and psbA DNA sequence analyses, Phytotaxa 606 (2), pp. 87-103 : 99

Corallina Linnaeus

— Both Jania rosea and C. berteroi are considered species complexes with high levels of phenotypic plasticity and near worldwide distributions ( Johansen and Womersley 1986, Calderon et al. 2021, Guiry and Guiry 2022). Not surprisingly Jania specimens from south-eastern Australia originally identified as J. rosea (LTB 18113, 18115, 18117, 18118, 18182), one of which was identified as J. rosea in Harvey et al. (2020), LTB18193, were molecularly identified in this study as C. berteroi based on psb A phylogenetic analyses ( Fig. 5 ). A recent multi-locus molecular systematics study of the C. berteroi species complex confirmed the wide range of phenotypic plasticity displayed by this species that most likely reflects adaptive responses of geographically distant populations to local environmental drivers ( Calderon et al. 2021). For example, C. berteroi from North Carolina, USA (NCU 628550) and from Peru (UC 1404138), reported in Calderon et al. (2021, fig.3E), resembles some J. rosea phenotypes from Australia ( Johansen & Womersley 1986, fig.1). Since J. rosea can be readily confused with C. berteroi by researchers with extensive knowledge of the two genera, and because the type locality of J. rosea is not fully known (therefore sequencing topotype material will not resolve this issue), the only conclusive method to confirm the correct application of the name J. rosea is to analyze DNA from the type material housed in PC.

In summary, our study provides the first molecular phylogenetic analysis of the south-eastern Australian Jania species. The results identify molecular differences among Australian species confirming the previous conclusions of Harvey et al. (2020). While a high degree of morphological overlap has been reported amongst some species groups such as J. penduculata varieties, J. micrarthrodia and J. rosea , the molecular data presented here was able to distinguish all previously described morphological species as distinct phylogenetic lineages. The molecular data suggests that the two J. pedunculata varieties may be distinct species, but a more detailed molecular and morpho-anatomical analysis encompassing additional Australian collections are needed before nomenclatural changes are proposed. Specimens identified as Jania micrarthrodia form a highly supported species so far restricted in distribution to Australia. Specimens identified as Jania sagittata were recognized as another well supported species based on molecular data that occurs in both Australia and New Zealand. Specimens identified as J. rosea in Australia and New Zealand are likely not the same species. Jania rosea in general is a highly variable morpho-anatomical species complex that needs to be addressed more specifically both in Australia and worldwide. Several specimens identified as J. rosea were also confirmed by both cox 1 and psb A phylogenies to be Corallina spp. further recognizing the need for genetic analyses to confirm taxonomic identifications in both genera. Future studies must attempt to include molecular data from type or topotype specimens to ensure the correct application of all epithets determined so far by the type method. Combined data from detailed taxonomic studies and molecular analyses from difference specimen sources are effective tools to jointly clarify taxonomic identifications and solve taxonomic conundrums in coralline systematics.

Figures

FIGURE 5. Maximum likelihood phylogenetic tree of Corallina species based on psbA DNA sequences. Numbers above branches represent non-parametric bootstrap support. Values <50 were omitted. Species names are followed by GenBank accession number. South-eastern Australian sequences produced in this study are marked in bold. Bossiella, Calliarthron and Arthrocardia were used as outgroups.