BRITISH CRETACEOUS ECHINOIDS

摘要

In this monograph 222 species of echinoid are described from the Cretaceous deposits of the British Isles. Nine genera and 22 species are new to science and many known species recorded from the British Isles for the first time. There are 36 cidaroid species, one echinothurioid, one diadematoid, 54 stirodont and nine camarodont species amongst the regular echinoids and seven holectypoid species, nine echinoneoid, 18 cassiduloid, 49 holasteroid and 45 spatangoid species amongst the irregulars. The early Cretaceous faunas remain poorly represented, largely because outcrops are sparse and facies inappropriate for the preservation of echinoids. Only a single Berriasian species, two Valanginian species and six Hauterivian species are known from this region. By contrast, the Cenomanian has the most diverse fauna, with 76 species. Diversity drops in the Turonian coincident with a sharp rise in sea-level that led to chalk facies dominating across the British Isles. It recovers somewhat in the Late Coniacian and Santonian, driven primarily by rising numbers of irregular echinoids, but is particularly poor in the Maastrichtian due entirely to a lack of outcrop.