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ABSTRACTUnderstanding how genetic variation is spatially distributed is necessary for understanding the processes that generate and maintain biodiversity. However, there has been little investigation into the phylogeography of widespread forest trees in Aotearoa New Zealand with studies to date showing little congruence in phylogeographic patterns. Pseudopanax crassifolius(lancewood/horoeka) is a widespread lowland forest tree endemic to Aotearoa New Zealand. We investigated the phylogeography of this species using microsatellites and chloroplast haplotypes and compare the results to published results from the closely-related P. ferox, which also has a widespread lowland distribution, but differs in its ecological preferences. Microsatellite genotypes revealed two weakly differentiated genetic clusters within P. crassifolius. One cluster comprised all individuals from the North Island plus those from the north-eastern and central-eastern South Island. The second cluster, which had lower levels of genetic variation than the northern cluster, encompassed the southern and western South Island. The southern cluster exhibited lower genetic diversity, particularly in the southern South Island, suggesting that the species was severely restricted, or even extirpated, from this region during the Last Glacial Maximum (LGM). This result contrasts with the high level of genetic structuring observed in the closely-related P. ferox. There was evidence of asymmetric chloroplast introgression from P. feroxinto P. crassifoliusin the south-eastern South Island. Alternative scenarios that may have led to this asymmetric introgression are discussed.

ABSTRACTThe term ‘eucheumatoids’ designates a group of genera in the family Solieriaceae that are the source of some of the most valuable algal products in cultivation. While economically important in the tropics, much of its taxonomy is yet to be fully resolved. The eucheumatoid species Mimica arnoldiiis a Batesian mimic of corals that was recently transferred to its own genus from Eucheumabased primarily on peculiarities of habit and a lack of medullary rhizoids, in contrast to the generitype Eucheuma denticulatumthat has the latter. We studied the diversity of Mimica arnoldiifrom samples collected in the Philippines to determine their genetic variation, relationships to other eucheumatoids, and whether its two distinct morphological expressions, which have been named as varieties, are genetically different. We produced a phylogeny using a three-gene concatenated dataset, and used the variable mitochondrial cox2-3 spacer to determine intraspecific variation and the degree of correlation between sequence-variation and varietal status. Our results showed that Mimicais a distinct genus, and that intra-specific molecular data did not correspond to the morphology-based varieties, although it did correlate with geographical distribution. Our results also indicate that Kappaphycus, as presently circumscribed, contains species with (Kappahycus alvarezii, K. striatusand K. malesianus) and without (Kapppahycus cottonii) internal medullary hyphal core, and that K. cottoniiis sister to the remaining Kappaphycusspecies. We thus propose Kappaphycopsis gen. nov. for K. cottoniifor the species of Kappaphycuswithout internal medullary rhizoids (anaxiferous).

ABSTRACTSchizymenia dubyiis reported as a new introduction in Wellington, which already has introduced S. apoda. These species coexist in tidepools and the crustose sporophyte is for the first time reported from this population. The diversity and species status of these two species was explored using mitochondrial, plastid and nuclear markers. Haplotypes of rbcL in New Zealand samples of S. dubyimatch a haplotype found in Australia that was considered as ‘introgressed’ into S. apoda. COI haplotypes of S. dubyifrom New Zealand are also similar to specimens from Australia and Europe, although New Zealand S. apodasamples have a unique haplotype. ITS ribotypes of S. dubyifrom New Zealand also are shared with Australia and Europe, while again S. apodaribotypes are unique. Phylogenetic and network analyses show that these two species are very closely related, and the hypothetical ‘introgressed’ nature of specimens is not supported by phylogenetic analyses. In addition, species delimitation methods are not congruent and do not clarify the species status of these two entities. Morphologically, these species are not distinct, except that in S. dubyithe cystocarp ostiole may be in a depression. The apparent incongruence between markers, leading to the hypothesis of introgression, is probably due to the early stages of the speciation process during which species have a ‘paraphyletic’ phase, in which stochastic incomplete lineage sorting leads to ancestral haplotypes being retained differentially, versus hybridization, introgression and non-maternal inheritance of organelles. Whether these two entities are distinct species needs to be reconsidered, as many species criteria are not met (e.g. monophyly) or need to be tested (e.g. reproductive barriers).

ABSTRACTTaxonomy and diversity of the Gracilariaceae has been increasingly investigated by using integrated morphological and genetic approaches. The Indo-Pacific is likely a hotspot for diversity of these macroalgae. Collections of flattened Gracilariasamples from Natai beach, Andaman coast of Thailand, were morphologically and genetically analysed. Our results clearly indicated the presence of a new species, G. khanjanapajiae sp. nov., in Thailand. In comparison to other known Indo-Pacific flattened species, G. khanjanapajiaecan be distinguished by its dentate blade margin, deep spermatangial conceptacles (verrucosa-type) and numerous lateral and basal nutritive filaments within mature cystocarps. This new species resembles G. srilankiain having similar branching pattern and male reproductive structures, but differs in blade margin features. Phylogenetically, G. khanjanapajiaewas more closely related to G. spinulosafrom Taiwan than other Thai and Indian Ocean species. This present study highlights the continuing discovery of Gracilariadiversity and distribution in the tropical Indo-Pacific.