Tracing Ice-Age Legacies: Phylogeography and Glacial Refugia of the Endemic Chiton Tonicina zschaui (Polyplacophora: Ischnochitonidae) in the West Antarctic Region
Ibanez, Christian M.
- 1Universidad Bernardo O'Higgins
- 2Pontificia Universidad Catolica de Chile
- 3Universidad de Chile
- 4Universidad Andres Bello
- 5
- 6University of Alabama System
Journal
Diversity
ISSN
1424-2818
Open Access
gold
Volume
17
Phylogeographic studies in Antarctica allow us to understand the demographic events of populations during glacial periods. In this study, the polyplacophoran Tonicina zschaui was analyzed in several localities on the West Antarctic Coast using the mitochondrial gene cytochrome oxidase subunit I (COI). Two genetically distinct populations were identified: one in the Weddell Sea and another across the Antarctic Peninsula and South Shetland Islands. Genetic diversity was generally low to moderate, suggesting limited gene flow and the influence of historical climatic events. Star-like haplotype networks and demographic analyses indicate population contractions during the Last Glaciation followed by postglacial expansion, especially in the Antarctic Peninsula-South Shetland Islands population. Several sites in this region were identified as potential glacial refugia, exhibiting proportionally elevated genetic diversity and exclusive haplotypes. Conversely, the small Weddell Sea population displayed signs of long-term isolation, limited expansion, and low diversity, likely due to stronger environmental constraints and genetic drift. Ocean currents such as the Antarctic Coastal Current, the Antarctic Peninsula Coastal Current and the Weddell Gyre appear to restrict larval dispersal, reinforcing genetic discontinuities. These findings support the hypothesis of glacial survival in localized refugia and postglacial recolonization, a pattern observed in other Antarctic marine invertebrates.
Name
diversity-17-00626-v2.pdf
Type
Main Article
Size
2.33 MB
Format
Adobe PDF
Checksum
(MD5):1725f9dac243a0046fe54091f94986a7
Attribution 4.0 International