NEW RECORD OF STALKED BOURGUETICRINIDS FROM NORTHEAST SPAIN

Bourgueticrinids are the youngest major group of living crinoids, first appearing in the Late Cretaceous. Commonly accepted as paedomorphic comatulids, bourgueticrinids are characterized by few arms (5-10), a simple cup, and a gracile stalk with synarthrial articulations on the columnals. Delicate in structure, most fossil bourgueticrinids are heavily disarticulated and complete specimens are rare; cups and columnals are often the defining features in species identification and inferring paleoecological data.

Although bourgueticrinid fossils well known from other parts of Europe, such as Poland and Demark, records from Spain are sparse. Recent fieldwork has yielded previously unrecorded bourgueticrinids from the Upper Cretaceous and Lower Eocene of northeast Spain. These findings expand the temporal range of several bourgueticrinid genera; the last occurrence of Bourgueitcrinus is extended from the Paleocene into the lower Eocene and the earliest occurrence of Democrinus moves back into the Campanian.

Numerous cups, columnals, and root structures collected further expand our understanding of bourgueticrinids paleoecology and paleoenvironment distribution. Many of the cups contain evidence of echinoid or fish predation, with one species showing nearly 30% of individuals having distinct predation marks. The Lower Eocene Bourgueticrinus is one of the latest shallow water stalked crinoids in the Cenozoic; supporting the idea that some stalked crinoids persisted in shallow water much later than once thought.