A new Pseudogibbaster Moskvin, 1983 (Echinoidea, Spatangoida) from the mid Danian (Paleocene) deep-shelf chalk of Denmark

Abstract

During the mid Danian, deep-water chalk accumulated in the central parts of the Danish Basin, which harboured a markedly impoverished macrobenthos fauna. Among the seven echinoid taxa recorded so far, five are atelostomates belonging to the deposit feeder guild. Here, a new species of the micrasterid echinoid genus Pseudogibbaster Moskvin, 1983, P. herkstroeteri, is erected to accommodate a single, moderately large-sized, fairly well-preserved test from Dalbyover, in northern Jutland, the only locality where mid-Danian deep-water chalk from the central part of the Danish Basin can be accessed. This is the first record of the genus from the Paleocene of NW Europe. Features that distinguish the new taxon from its congeners are the relatively large size, rectangular test profile and conspicuously large and countersunk phyllodal pores. The latter corresponded with large penicillate podia and are interpreted as an adaptation to the nutrient-deficient bottom conditions by optimizing the ability of bulk sediment feeding.