New species of sponges from Cenozoic Tethys

Sponges are important components of modern and fossil aquatic environments. However, little is known about their communities that inhabited the Tethyan areas during the Cenozoic. We recorded a surprisingly rich sponge spicule assemblage of the middle–late Eocene from east-central Ukraine. The sponge community comprised at least 34 sponge taxa (including demosponges, hexactinellids and a homoscleromorph) and inhabited shallow, 100-m-deep waters. Two new demosponge taxa, Paratetilla milanek and Theonella alexandriae Łukowiak were established. Additionally, we report the first fossil occurrence of Vetulina, a demosponge genus that currently lives near the Australia and Philippines and in the Caribbean Sea. Some of the sponge taxa recognized were previously noted from the upper Eocene of Australia and New Zealand. This is indicative of their wide distribution during the early Cenozoic and also shows that a non-interrupted connection existed between the western Tethyan and peri-Australian areas.

Illustration: Paratetilla milanek Łukowiak sp. nov.,; A, articulated sponge body. B, diagram of the arrangement of spicules, indicating the relative positions of the elements shown in C–H. Scale bars: 5 mm (A, B); 20 μm (C–H; C′–H′).