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Abstract Many subspecies were described to capture phenotypic variation in wide-ranging taxa, with some later being found to correspond to divergent genetic lineages. We investigate whether currently recognized subspecies correspond to distinctive and coherent evolutionary lineages in the widespread Australian lizard Ctenotus pantherinus based on morphological, mitochondrial and genome-wide nuclear variation. We find weak and inconsistent correspondence between morphological patterns and the presumed subspecies ranges, with character polymorphism within regions and broad morphological overlap across regions. Phylogenetic analyses suggest paraphyly of populations assignable to each subspecies, mitonuclear discordance and little congruence between subspecies ranges and the distribution of inferred clades. Genotypic clustering supports admixture across regions. These results undermine the presumed phenotypic and genotypic coherence and distinctiveness of C. pantherinus subspecies. Based on our findings, we comment on the operational and conceptual shortcomings of morphologically defined subspecies and discuss practical challenges in applying the general notion of subspecies as incompletely separated population lineages. We conclude by highlighting a historical asymmetry that has implications for ecology, evolution and conservation: subspecies proposed in the past are difficult to falsify even in the face of new data that challenge their coherence and distinctiveness, whereas modern researchers appear hesitant to propose new subspecies.
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A phylogenomic perspective reveals mitochondrial-nuclear discordance and previously undescribed species nested within a widespread East African Reed frog species (Hyperolius substriatus Ahl, 1931)
The sub-montane East African Reed Frog,Hyperolius substriatusAhl, 1931 (Spotted Reed Frog) has a fragmented highland distribution throughout East Africa. Previous studies show extensive mitochondrial divergence between four lineages of African Spotted Reed Frogs that roughly correspond to previously-recognized subspecies. These may have conservation implications if formally described. However, as mitochondrial-based population models only track maternal patterns, further genomic datasets are necessary to assess the distinctness of these lineages in relation to historically recognized morphological subspecies. In this study, we expanded sampling to newly discovered localities and assessed mitochondrial and genomic data to better understand phylogeography and landscape genomics of this species. We found that genomic clades (biparentally inherited) confirm some of the mitochondrial structure (female inherited), but also revealed multiple cases of mitonuclear discordance particularly within the Udzungwa Mountain block, which may have two separate founding events based on peripatric mitochondrial lineages and panmictic genomic signals. Taken together, the three clades within the geographical range ofH. substriatusthrough Tanzania, Malawi, and Mozambique correspond to three previously-identified subspecies and lineages, and have both spatially cohesive and population-specific patterns of geneflow and isolation with neighboring highland locations.
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- Award ID(s):
- 2020886
- PAR ID:
- 10629580
- Editor(s):
- Meegaskumbura, Madhava
- Publisher / Repository:
- the Public Library of Science (PLOS)
- Date Published:
- Journal Name:
- PLOS ONE
- Volume:
- 20
- Issue:
- 4
- ISSN:
- 1932-6203
- Page Range / eLocation ID:
- e0318951
- Subject(s) / Keyword(s):
- mitochondrial-nuclear discordance phylogenomics phylogeography African amphibians montane amphibians
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1371/journal.pone.0318951
