Pentasteria? splendida, a new Early Cretaceous astropectinid starfish from northern Germany

Abstract

A new species of early Hauterivian (Early Cretaceous) astropectinid starfish, Pentasteria? splendida, is recorded from strata assigned to the Endemoceras amblygonium ammonite Zone at Engelbostel, near Hannover (northern Germany). Although based solely on a lightly pyritised proximal arm fragment (most likely the result of a predator attack, which is also suggested by possible bite marks), preservation is otherwise excellent, with numerous spines on inferomarginals and adambulacrals retained. Distinguishing features include a distal row of three equal-sized spines on the oral surface of inferomarginals, plus two oblique rows of horseshoe-shaped spine bases on their lateral surface bearing spines of variable length, as well as the absence of large spine pits on superomarginals and adambulacrals. Two oral intermediate ossicles close to the disc margin apparently possess larger spine bases. For the time being, assignment to the family Astropectinidae is based on the occurrence of multiple spines on inferomarginal ossicles and paxilliform adoral ossicles, but placement in the genus Pentasteria is tentative, because superomarginal ossicles have closely spaced small granules rather than scale-like spinelets.