Tubiphytes

Tubiphytes is a genus of enigmatic marine microfossils of uncertain biological classification, found as encrusting or cylindrical aggregates of sparite filled chambers surrounded by a cortex, ranging from the Carboniferous through the Triassic period. Its true nature has been debated among sponges, red algae, cyanobacteria, hydrozoans and foraminiferans, and the genus is currently left with its class and order both listed as uncertain. Fossils assigned to Tubiphytes contributed to reef systems of the Paleozoic and Mesozoic, though similar Cretaceous material has since been reassigned to the separate genus Crescentiella.