Danian (Early Paleocene) echinoids from the Roca Formation,northern Patagonia

DEL RIO, C. CONCHEYRO, Y MARTINEZEZ, S.

NEUES JAHRBUCH FUR GEOLOGIE UND PALAONTOLOGIE-ABHANDLUNGEN

E SCHWEIZERBARTSCHE VERLAGS

Lugar: Stuttgart; Año: 2011 vol. 261 p. 165 - 176

0077-7749

Stratigraphically well constrained echinoids from the Roca Formation in the province of Rio Negro (Patagonia, Argentina) are analysed in detail. The poorly known Linthia? joannisbohemi recently to reassigned to Parster,is demonstrated to comprise in fact two distinct species, Linthia joannisbohemi and Linthia parmae n.sp. In addition , especifically indeterminate species of Plesiaster and Hemiaster and a basal holoasteroid are recorded. The analyses of calcareous nanofossil assemblages of the echinoid -bearing strata document their early Paleocene ( Danian) age, which was an impact on patterns of survirvorship across the K/Pg boundary.