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Abstract AimWe explore the biogeographic history of the Gondwanan lineage Triaenonychidae, a dispersal‐limited arachnid taxon that underwent a recent taxonomic revision based on phylogenomic data. We explicitly test hypotheses related to a biogeographical pattern of ‘common vicariance, rare dispersal’, predicted for dispersal‐limited taxa. LocationContinental landmasses of former temperate Gondwanan terranes (southern South America, southern Africa, Madagascar, Australia, New Zealand, and New Caledonia). TaxonTriaenonychidae, Opiliones, Arachnida. MethodsUtilizing a recently published phylogenomic data set based on ultra‐conserved elements, we conduct Bayesian divergence dating analyses, ancestral area estimation in a likelihood model testing framework, and analyses of macroevolutionary dynamics. Results are correlated with geological history and palaeoclimate reconstructions to infer biogeographic history and distribution. ResultsWe find that divergence dates of ancestral Triaenonychidae pre‐date continental breakup of Gondwana and could be attributed to palaeoclimatic differentiation across Gondwana. There is evidence for two separate expansion routes that span eastern and western Gondwana corresponding to northern warmer climate and southern cooler climate lineages. Many divergences across intercontinental lineages coincide with the timing of continental fragmentation, supporting vicariance as a dominant force. However, some lineages are supported as obvious examples of rare long‐distance dispersal. Biogeographic results support the predicted pattern of common vicariance and rare dispersal for these dispersal‐limited organisms. Main conclusionsVicariance due to continental fragmentation was important in the early diversification of Triaenonychidae. Their unique combination and degrees of dispersal ability and microhabitat preference resulted in complex phylogenetic patterns of geographic distribution not typically seen in other animal taxa. Examining biogeographic patterns across recent studies of arachnid taxa with varying dispersal ability, it is clear that biological characteristics play an important role in the relative importance of dispersal and vicariance (dispersal–vicariance continuum) for any given taxon and can be useful in forming testable a priori hypotheses.
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Fossils indicate marine dispersal in osteoglossid fishes, a classic example of continental vicariance
The separation of closely related terrestrial or freshwater species by vast marine barriers represents a biogeographical riddle. Such cases can provide evidence for vicariance, a process whereby ancient geological events like continental rifting divided ancestral geographical ranges. With an evolutionary history extending tens of millions of years, freshwater ecology, and distribution encompassing widely separated southern landmasses, osteoglossid bonytongue fishes are a textbook case of vicariance attributed to Mesozoic fragmentation of the Gondwanan supercontinent. Largely overlooked fossils complicate the clean narrative invoked for extant species by recording occurrences on additional continents and in marine settings. Here, we present a new total-evidence phylogenetic hypothesis for bonytongue fishes combined with quantitative models of range evolution and show that the last common ancestor of extant osteoglossids was likely marine, and that the group colonized freshwater settings at least four times when both extant and extinct lineages are considered. The correspondence between extant osteoglossid relationships and patterns of continental fragmentation therefore represents a striking example of biogeographical pseudocongruence. Contrary to arguments against vicariance hypotheses that rely only on temporal or phylogenetic evidence, these results provide direct palaeontological support for enhanced dispersal ability early in the history of a group with widely separated distributions in the modern day.
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- Award ID(s):
- 2017822
- PAR ID:
- 10533977
- Publisher / Repository:
- Royal Society
- Date Published:
- Journal Name:
- Proceedings of the Royal Society B: Biological Sciences
- Volume:
- 291
- Issue:
- 2028
- ISSN:
- 0962-8452
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1098/rspb.2024.1293
