Jania crassa J.V.Lamouroux

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 : 97

Jania crassa J.V.Lamouroux

—Woelkerling et al. (2015a) reported J. verrucosa as a heterotypic synonym of J. crassa . Jania crassa has been traditionally reported from subtropical and tropical coasts around the world, including Australia (Womersley and Johansen 1994, Woelkerling et al. 2015a), New Zealand ( Woelkerling and Nelson 2004), Brazil ( Wallace et al. 2003), and China ( Xia et al. 2013). Our psb A results confirmed that all Australian, Spain and New Zealand J. crassa specimens form a monophyletic group with maximum phylogenetic support. The results here corroborate the current biogeographic hypothesis that J. crassa is widely distributed across the world.

Due to the fact that different researchers have been using different markers to study Jania systematics, we were unable to determine whether one of the two South African J. crassa cox 1 clades from Kogame et al. (2017) belong to or are phylogenetically related to the Australian, New Zealand and Spain J. crassa psb A clade. A psb A singleton from New Zealand (MK413379), morphologically identified as J. crassa by Twist et al. (2019), is phylogenetically unrelated to the main J. crassa clade ( Fig. 3 ). If not a case of simple mix-up or misidentification, MK413379 may represent a rare new endemic species from New Zealand ( Fig. 4 ). Future examination of herbarium specimens from the same locality as the MK413379 specimen may clarify this issue (outside the scope of this study). Psb A and cox 1 were not able to determine the phylogenetic position of J. crassa singletons MK413379 and LC071784, respectively, due to the lack of phylogenetic support, with the exception of the psb A Bayesian tree (Figs 1,2) which showed high phylogenetic support for MK413379 as a sister species to Jania cf. rosea also from New Zealand.

Lugilde et al. (2019) reported Jania longifurca Zanardini from specimens collected in northern Spain, Galicia, using morpho-anatomical and psb A phylogenetic analyses. We included their psb A sequences in our analyses. Our phylogenetic and SDM results showed that the population identified as J. longifurca from Atlantic Spain corresponds to the same entity as J. crassa from Australia and New Zealand identified by Harvey et al. (2020) and Twist et al. (2019), respectively (Figs 3,4). It is likely that J. longifurca should be synonymized with J. crassa , however further analysis of topotype material of J. longifurca or the lectotype specimen of this species is required to support this systematic conclusion. The Lugilde et al. (2019) study convincingly showed how phenotypically plastic specimens of J. crassa can show high morphological variation related to the environment, e.g., deeper maërl or stable rocks substrate. Changes in J. crassa habit in Galicia was attributed to changes in substrate type, including associated microhabitat conditions that the specimens grew on. The atypical prostate morphology grows on mäerl beds and is characterized by thin intergenicula, irregular dichotomous branching, and the presence of secondary attachment discs. The typical longer, erect, robust form grows on intertidal and subtidal rock substrate. The great capacity of J. crassa to adapt its morphology to inhabit distinct local micro-habitats might be one reason why this species has been able to successfully colonize a wide geographic range and multiple oceans. The main and first morphological character used to start the morpho-anatomical identification key to species of Jania confirmed to occur in south-eastern Australia from Harvey et al. (2020) is whether the branching pattern is either (predominantly) dichotomous or pinnate. As documented by Lugilde et al. (2019), J. crassa , as well as J. rosea from southern Australia (Gurgel, pers. observ.), can express both morphotypes, often on the same specimen. Such drastic phenotypic plasticity in a widely distributed species contributes to widespread species misidentifications in the literature. Future species identification, phylogenetic and taxonomic studies, classification proposals, and descriptions of new Jania species will ultimately rely on a mix of molecular data, supported and reinforced by detailed anatomical/morphological data.

Figures

FIGURE 3. Maximum likelihood phylogeny of Jania species based on psbA gene focusing on specimens from south-eastern Australia. Numbers above branches represent non-parametric bootstrap support (values <70 omitted). Species names are followed by GenBank accession number and specimen locality (for sequences downloaded from GenBank), or species name, herbarium codes for all specimens sharing that particular haplotype, and specimen locality (marked in bold for sequences produced in this study). Scale bar = substitutions per site.

FIGURE 4. Bayesian phylogenetic tree of Jania species based on psbA gene with focus on specimens from south-eastern Australia. Numbers above branches represent posterior probabilities (values <0.5 omitted). Specimens sequenced in this study are marked in bold and have their herbarium code identified. Colored columns indicate species delimitation results: ABGD; ASAP P (p-value partition), ASAP W (w rank partition); GMYC S (single-threshold), GMYC M (multiple-threshold); PTP B (Bayesian inference), PTP M (Heuristic or Maximum Likelihood); and SPN 95% and 99% of parsimony probability limit. Black column indicates the consensus across all species delimitation results. Numbers below each column indicate the total number of species partitions for each method, including the consensus.