spongioiduns

Spongioiduns is a genus of demosponges that was first described in the early 21st century from fossil fragments recovered in the Late Jurassic strata of the Morrison Formation. The name derives from the Latin “spongiosus” meaning sponge‑like, combined with the suffix “‑uns,” which in this context refers to the distinctive undulated surface patterns observed on their spicules.

Taxonomically, Spongioiduns belongs to the class Demospongiae, order Haplosclerida, and is closely related to the extant genera Tethya and Montastraea. The genus was established based on a set of diagnostic morphological features that include a porous spicule framework composed of both tylostyles and microscleres, as well as an extensive calcitic skeleton that is uncommon among Jurassic sponges.

Morphologically, Spongioiduns specimens exhibit a globular to ellipsoid body form, with a diameter ranging from 5 to 15 centimeters. The outer surface is irregularly ridged, giving the sponges a highly textured appearance. Internally, the canals are well‑developed, suggesting efficient water filtration capabilities. The porosity of the skeleton may have provided mechanical support while allowing for the containment of symbiotic microorganisms.

Ecologically, the prevalence of Spongioiduns in the Morrison Formation indicates a shallow marine environment with moderate water depths and abundant particulate matter. Their calcitic skeletons have been found in association with bivalve and gastropod shells, implying a community structure dominated by filter feeders.

Because Spongioiduns is represented solely by fossil material, its biology remains partially speculative. Nevertheless, the distinct skeletal architecture and the combination of spicule types have made it a useful taxon for biostratigraphic dating within Late Jurassic marine deposits.