Post by grrraaahhh on Nov 10, 2010 20:36:04 GMT -9
The European descendants of Ursus etruscus C. Cuvier (Mammalia, Carnivora, Ursidae).
This paper deals with a review of the Pleistocene Bears origin, evolution, and stratigraphical distribution.
U. ruscinensis DEP. could be considered the common ancestor of all the European Pleistocene Bears, as the source of two evolutive lineages: one the more conservative, U. mecliterraneus F. MAJOR, and another the more evolved which starts with U. etruscus G. CUV. and gave origin o two evolutive trends: the today vanished speloid one (U. deningeri v. REICH, and U. spelaeus ROS.-HEIN) and the still living artoid one which is represented today in the true brown bear (U. arctos LIN.).
U. minimus DEV.-BOUILL. does not constitute a link between U. ruscinensis and U. etruscus: it is a lateral branch, in the general evolutionary schedule, more evolved than U. etruscus. Recent findings of arctoid Ursidae remains in the Iberian Peninsula, ranging from Lower to the Middle (Upper) Pleis tocene, allowed us to think that the general migration southwards of an Asiatic Brown bear population during the Wurm glacial period beginning, superimposed on an authochtonous European Brown bear population (prearctoid): U. prearctos BOULE, which is the probable ancestor of the polar bear [U. maritimus PHIP.).
Key words: Ursidae, Phylogeny, Stratigraphy, Pleistocene, Europe.