ROSSELLA BROMLEYI N. SP.: THE FIRST ENTIRELY PRESERVED FOSSIL SPONGE SPECIES OF THE GENUS ROSSELLA (HEXACTINELLIDA) FROM THE UPPER CRETACEOUS OF BORNHOLM, DENMARK

Abstract

A new lyssacinosan hexactinellid, Rossella bromleyi n. sp., is described from the Upper Cretaceous of Arnager Pynt, Bornholm (Denmark). The sponge shows a cup-shaped form with a broad, moderately dense root tuft, which contains three- and four-rayed orthotropal anchors characteristic for Rossella. The skeleton is composed of bundles of diactines, hexactines of two orders, and pentactines. Diactine bundles are mainly in the growth direction or diagonal to it. Prostalia lateralia are pentactines with the paratangential rays protruding beyond the outer surface of the sponge body. Hypodermalia are absent.