A Mississippian hexactinellid sponge from the Western Gondwana: Taxonomic and paleobiogeographic implications

CARRERA, MARCELO; RUSTAN, JUAN; VACCARI, NORBERTO; EZPELETA, MIGUEL

ACTA PALAEONTOLOGICA POLONICA

INST PALEOBIOLOGII PAN

Lugar: Varsovia; Año: 2018 vol. 63

0567-7920

A Mississippian hexactinellid sponge from the western Argentina improves the extremely poor late Paleozoic spongerecords from Gondwana. The sponge is included in the subfamily Thysanodictyinae of family Dictyospongiidae. The newgenus and species Minitaspongia parvis is erected, and its well-preserved spicular structure is described in detail representingthe first approximation of the spicule assemblage in Thysanodictyinae. The skeleton is clathrate, three-dimensionalwith at least two ranks of rectangular openings. This first report of this subfamily outside North America represents thebest-known hexactinellid and the first dictyosponge record from the Carboniferous of Gondwana. Unlike the occurrencesof Thysanodictyinae in North America, with thick skeletons linked to high-energy shallow water settings, Minitaspongiaoccurs in low-energy water siliciclastic settings related to a cold climate and glacimarine deposits. Accordingly, the complexwall structure of this sponge should not be invoked as a necessary adaptation to high energy and shallow water settings.