Ordovician sponges from the Lenoir Limestone, Tennessee: new evidence for a differential sponge distribution along the margins of Laurentia

CARRERA, MARCELO G.; SUMRALL, COLIN D.

JOURNAL OF PALEONTOLOGY

PALEONTOLOGICAL SOC INC

Lugar: Lawrence; Año: 2019 p. 1 - 11

0022-3360

Abstract.Five genera of anthaspidellid and streptosollenid demosponges are described from the Ordovician LenoirLimestone near Lenoir City, Loudon County, Tennessee, USA including: Rhopalocoelia regularis Raymond andOkulitch, Rugocoelia loudonensis n. sp., Psarodictyum sp. (Anthaspidellidae), Allosacus pedunculatus n. sp., andZitelella varians Raymond and Okulitch (Streptosolenidae). These findings confirm the major paleobiogeographicpicture for Laurentian sponges (i.e., the differential distribution of sponge faunas along both North American margins),because none of these eastern margin species has been reported from western margin faunas. Only one genus typical ofthe Great Basin fauna, Rugocoelia Johns, 1994, is reported from Tennessee, but as a new species. Possible explanationsare discussed for this differential distribution, mainly related to climatic constraints or sedimentary differences,preventing the free distribution of sponge species between Laurentian continental margins