The Fossil Record of the Clam Shrimp (Crustacea; Branchiopoda)

A Review of Recently Discovered Remains of the Pleistocene Branchiopods (Anostraca, Notostraca) from NE Siberia and Arctic Canada

In this study, we examine, identify, and discuss fossil remains of large branchiopod crustaceans collected from six sites across the Beringian region (north-eastern Asia and north-western North America). Eggs and mandibles from Anostraca and Notostraca, as well as a notostracan telson fragment and a possible notostracan second maxilla, were collected from both paleosediment samples and also from large mammal hair. The remains of large branchiopods and other species that are limited to seasonally astatic aquatic habitats (temporary wetlands) could be useful indicator organisms of paleoecological conditions. Different recent large branchiopod species have very different ecological preferences, with each species limited to specific geochemical component tolerance ranges regarding various salinity, cation, and gypsum concentrations. Our purpose is to bring the potential usefulness of these common fossil organisms to the attention of paleoecologists.

Revision of Two Spinicaudatan Species from the Cañadón Asfalto Formation (Jurassic), Patagonia Argentina

Re-examination under a scanning electron microscope (SEM) of the type material of the species described by Tasch and Volkheimer (1970) and Vallati (1986) was applied, as well as, new materials collected from different localities of the Las Chacritas Member from Cañadón Asfalto Formation (Argentina). Morphological description and new SEM images of the ornamentation pattern revealed features on carapaces that had not been recognized previously. These species are now referred to the family Eosestheriidae as Carapacestheria taschi (Vallati, 1986) and to the family Fushunograptidae as Wolfestheria patagoniensis (Tasch, in Tasch and Volkheimer, 1970). These records increase our knowledge about the Jurassic faunas from Argentina.