Differential extinction and the contrasting structure of polar marine faunas

• Published in: PloS one Vol. 5; no. 12; p. e15362
• Main Authors: Krug, Andrew Z, Jablonski, David, Roy, Kaustuv, Beu, Alan G
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 22-12-2010; Public Library of Science (PLoS)
• Subjects: Animals; Antarctic Regions; Biodiversity; Biogeography; Biological Evolution; Biology; Bivalvia; Cenozoic; Climate change; Comparative analysis; Earth sciences; Ecosystem; Endangered & extinct species; Evolution; Extinct species; Extinction; Extinction (Biology); Fossils; Geography; Geology; Glaciation; Glaciology; Global cooling; Local extinction; Marine Biology; Models, Biological; Mollusca; Myoida; Paleobiology; Paleontology; Phanerozoic Eon; Phylogenetics; Phylogeny; Polar environments; Predators; Prey; Pterioida; Sediments; Shellfish; Species extinction; Thyasiridae; Time Factors; Veneroida; Antarctic Regions; Colville River; United States > US; Arctic region; Illinois; Arctic Ocean; Alaska; Antarctica; Chicago Illinois; California; North Slope
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0015362

The low taxonomic diversity of polar marine faunas today reflects both the failure of clades to colonize or diversify in high latitudes and regional extinctions of once-present clades. However, simple models of polar evolution are made difficult by the strikingly different faunal compositions and community structures of the two poles.
A comparison of early Cenozoic Arctic and Antarctic bivalve faunas with modern ones, within the framework of a molecular phylogeny, shows that while Arctic losses were randomly distributed across the tree, Antarctic losses were significantly concentrated in more derived families, resulting in communities dominated by basal lineages. Potential mechanisms for the phylogenetic structure to Antarctic extinctions include continental isolation, changes in primary productivity leading to turnover of both predators and prey, and the effect of glaciation on shelf habitats.
These results show that phylogenetic consequences of past extinctions can vary substantially among regions and thus shape regional faunal structures, even when due to similar drivers, here global cooling, and provide the first phylogenetic support for the "retrograde" hypothesis of Antarctic faunal evolution.