New species of Eucystis (Blastozoa: Echinodermata) from Laurentia: implications for morphological and biogeographical patterns in the Paleozoic

Abstract

A number of echinoderm groups lack representation in the Silurian fossil record, which becomes especially clear when considering the echinoderm fossil record of the Ordovician and Devonian. This paucity constrains our ability to resolve echinoderm evolutionary dynamics and biogeographic pathways during the Silurian, thereby underscoring the significance of newly discovered species. Herein, we describe a new species of blastozoan diploporan echinoderm, Eucystis charlotteae new species, from the Silurian of Missouri, USA, representing the first example of this genus described from Laurentia, which now makes this one of the most broadly distributed genera within diploporans. Within this paper, we compare and contrast this new species to other known species within Eucystis Angelin, 1878 . Eucystis charlotteae n. sp. is characterized by having five ambulacral grooves that branch three times into unequal lengths and each end in large, tumid facetal scars. Eucystis charlotteae n. sp. is also relatively large when compared to other named species of the genus, which could lend insight into body size trends of diploporan echinoderms in the early Paleozoic. This new occurrence also lends insight into the biogeographic dynamics of diploporan taxa across the early Paleozoic.

UUID: http://zoobank.org/4e64fd0d-f7f5-4f0e-a310-438bad08f046