Early Jurassic South American pectinaceans and circum-Pacific palaeobiogeography

DAMBORENEA, S.E.

PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY

Elsevier

Lugar: Amsterdam; Año: 1993 vol. 100 p. 109 - 123

0031-0182

In the light of new data from South America high-latitude southern bivalve faunas are now recognized for the Early Jurassic. It is proposed that an Austral Realm was in continuous existence throughout Jurassic times. Some bivalve genera (Palmoxytoma, Kolymonectes, Radulonectites, Agerchlamys n. gen.) and groups of species of Plicatula (Harpax) show a bipolar distribution suggesting climatic control. In the Early Jurassic, a distinctive group of high-latitude bivalves included Monotidae, Kalenteridae, Oxytomidae and some Pectinidae and Plicatulidae. Based on the pectinacean (s.l.) bivalves, the east-west faunal differentiation was weaker than the latitudinal one in the Early Jurassic Pacific. The southern Andes were situated in a trasitional area between the Tethyan and Austral realms, as shown by the mixed influence of the local bivalve faunas.