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ABSTRACT AimTo assess the origin, biogeographic history of threeTherorhodionspecies in the Pacific region; to reveal the differentiation withinT. camtschaticumacross its range from Beringia to Japan; and to discuss the role of Beringia as a refugium in the past and the future. LocationNortheast Asia and Western North America. MethodsWe analysed 122 original specimens of three species (T. redowskianum,T. glandulosumandT. camtschaticum) from Russia, China, the United States and 43 GenBank accessions from Japan, using seven nuclear loci. We use different approaches to infer genetic structure, divergence time estimations, ancestral area reconstructions and species distribution modelling to better understand the history of the mountain flora in the Pacific region. ResultsThree genetic clusters with an origin in northeast Asia corresponding to the three species were distinguished. The divergence time betweenT. redowskianumand the other two species was estimated at 19.2 Mya and betweenT. glandulosumandT. camtschaticumwas estimated at 2.13 Mya. WithinT. glandulosumandT. camtschaticum, no Western or Eastern Beringian clades were recovered. At the same time, two subclusters were inferred withinT. camtschaticum, one including populations from Kamchatka, the Aleutian Isl., the Kuril Isl. and partly Japan, and a second one including other populations from Japan, Sakhalin and Khabarovsk, which were identified with a divergence time estimation at 228 Ka BP. Species distribution modelling revealed that the global distribution area during the LGM remained relatively stable for all three taxa, although we observed some local geographical contractions. In contrast, global range contractions for the three species were predicted for the LIG and future climatic changes in 2061–2080. Main ConclusionsWe show thatTherorhodionoriginated in northeast Asia and diverged during the cooling of the late Miocene, with further diversification and dispersal across the Bering land bridge during the late Pliocene‐Pleistocene. Although previous studies found no obvious signs of hybridisation between species in their range overlaps, we revealed traces of some genetic contribution ofT. glandulosuminT. camtschaticumpopulations in Khabarovsk Krai. This study highlights the significance of the including samples from entire range of a species and using different types of markers for adequate biogeographic inferences. It also supports the role of Beringia as a refugium for arctic flora not only in the past, but also into the future.
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Phylogeny of Arbacia Gray, 1835 (Echinoidea) Reveals Diversification Patterns in the Atlantic and Pacific Oceans
ABSTRACT AimThe aim of the current study is to conduct a comprehensive phylogenetic analysis of the genusArbaciato elucidate the evolution and phylogenetic relationships among all extant species and reevaluate the presence of geographic structure within species that have wide, fragmented distributions. LocationSpecimens ofArbaciawere collected from 34 localities spanning the Atlantic and Pacific Oceans, and the Mediterranean Sea. MethodsWe obtained sequences from three mitochondrial markers (COI, 16S and the control region and adjacent tRNAs) and two nuclear markers (28S and 18S; the latter ultimately excluded from the final analyses). Phylogenetic trees were constructed using maximum likelihood and Bayesian inference approaches. A time‐calibrated phylogenetic tree was inferred using a relaxed Bayesian molecular clock and three fossil calibration points. ResultsOur analysis supports the monophyly of the genusArbacia, including the speciesArbacia nigra(previously assigned to the monotypic genusTetrapygus). The new phylogenetic topology suggests an alternative biogeographic scenario of initial divergence between Atlantic and Pacific subclades occurring approximately 9 million years ago. The dispersal and subsequent diversification of the Pacific subclade to the southeast Pacific coincides with the onset of glacial and interglacial cycles in Patagonia. In the Atlantic subclade, the split betweenA. punctulataandA. lixulaoccurred 3.01–6.30 (median 3.74 million years ago), possibly associated with the strengthening of the Gulf Stream current connecting the western and eastern Atlantic. Our study also reveals significant genetic and phylogeographic structures within both Atlantic species, indicating ongoing differentiation processes between populations. Main ConclusionOur study provides valuable insights into the evolutionary history and biogeography of the genusArbaciaand highlights the complex interplay between historical climate changes and oceanic currents in shaping the distribution and diversification of echinoids in the Atlantic and Pacific Oceans.
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- PAR ID:
- 10580341
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Journal of Biogeography
- Volume:
- 52
- Issue:
- 3
- ISSN:
- 0305-0270
- Page Range / eLocation ID:
- 722 to 734
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1111/jbi.15070
