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Genetic diversity of sympatric Schizymenia dubyi and S. apoda (Schizymeniaceae, Rhodophyta) in Wellington Harbour, New Zealand

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posted on 19.09.2022, 20:50 authored by Giuseppe ZuccarelloGiuseppe Zuccarello, R D’Archino
Schizymenia dubyi is 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. dubyi match a haplotype found in Australia that was considered as ‘introgressed’ into S. apoda. COI haplotypes of S. dubyi from New Zealand are also similar to specimens from Australia and Europe, although New Zealand S. apoda samples have a unique haplotype. ITS ribotypes of S. dubyi from New Zealand also are shared with Australia and Europe, while again S. apoda ribotypes 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. dubyi the 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).

History

Preferred citation

Zuccarello, G. C. & D’Archino, R. (2022). Genetic diversity of sympatric Schizymenia dubyi and S. apoda (Schizymeniaceae, Rhodophyta) in Wellington Harbour, New Zealand. Phycologia, 61(5), 549-557. https://doi.org/10.1080/00318884.2022.2090122

Journal title

Phycologia

Volume

61

Issue

5

Publication date

01/01/2022

Pagination

549-557

Publisher

Informa UK Limited

Publication status

Published

Online publication date

27/06/2022

ISSN

0031-8884

eISSN

2330-2968

Language

en