Phyllocarid crustaceans from the Devonian of Bolivia and a review of their occurrences in the South American Palaeozoic
Résumé
The Ordovician phyllocarids of South America, from the epoch preceding formation of the Malvinokaffric Realm, are pelagic caryocaridids of virtually pandemic distribution. Phyllocarids are unknown from the South American Silurian, presumably in result of environmental and taphonomic factors connected with glaciation of Gondwana, which prevented their life and/or fossilization. In the Devonian, the phyllocarid fossil record is restricted to Bolivia. The small-sized and having a thin exoskeleton Poupelicaris elegans n.g., n. sp. from the Lochkovian of Bolivia is the first 'Malvinokaffric' phyllocarid faunal element. The cool-water conditions that are considered to characterize the Malvinokaffric Realm ended in the Givetian with the incoming of the phyllocarid Dithyrocaris and, later, Paraechinocaris, probable immigrants from North America.