Paleobiogeographic patterns of decapod crustaceans from the Southern Hemisphere, based upon 441 species-level records arrayed in 154 genera, document global patterns of distribution that can be compared to those previously published on decapods from the North Pacific and Central American regions. All known records of decapods from the Southern Hemisphere spanning the Early Triassic to Pleistocene have been compiled, nearly all have been personally verified, and patterns of origin and distribution have been interpreted. Interchange between hemispheres, including amphitropical and bipolar distributions, are recognized from Jurassic to post– Miocene time. The high southern latitudes was a site of origin of several generic-level taxa during the Jurassic through Eocene and many of these taxa have been identified in subsequent times in lower latitude regions in shallow- and deepwater environments in both hemispheres. The isolation of Antarctica due to ocean currents significantly diminished the role of the high southern latitudes as an area of origin for decapods. The Tethys was an important dispersal pathway for decapods during the Cretaceous through early Miocene. Endemism was high during the Eocene, similar to the North Pacific and Central America. The magnitude of the Cretaceous/Paleogene extinction event on the Southern Hemisphere decapod fauna was not profound; most Cretaceous extinctions seem to have occurred well before the end of the Cretaceous, and 85% of the Cretaceous families are known from the Paleogene in the Southern Hemisphere taxa.
New Miocene Decapoda (Thalassinidea; Brachyura) from Tierra del Fuego, Argentina: Paleobiogeographic Implications01/01/2011
A decapod crustacean fauna of Tierra del Fuego, Argentina, is documented from the middle Miocene Carmen Silva Formation and the early? Miocene Cerro Águila Conglomerate of the Cabo Domingo Group. Three new genera and five new species are named: Asthenognathus australensis, new species; Miotymolus quadratus, new genus and species; Mursia fuegiana, new species; Pharkidodes agele, new genus and species; and Tierrapilumnus edseli, new genus and species. Compilation of all described species of decapods from late Oligocene to early Pliocene exposures in 18 general localities in Patagonia, southern Argentina, and Chile documents two paleobiogeographic provinces, Argentine and Chilean. Coupled with evidence from the biogeographic patterns of associated mollusks, the faunas from Tierra del Fuego have been assigned to the Argentine Paleobiogeographic Province. Comparison of the distribution of Miocene decapods with that of extant decapods (Boschi 2000) leads to the conclusion that the thermal separation of South Atlantic and South Pacific water in the Miocene was more pronounced than today, so that there is no evidence of a discrete Magellanic Biogeographic Province characterizing the high southern latitude region during the Miocene.