Strombids

Strombids are a genus of extinct rotifers found in freshwater sediments around the world. They are one of the most well-preserved and abundant fossil invertebrates in the fossil record.

The strombid rotifers were primarily detritivores, feeding on planktonic algae, bacteria, and small particles in the water column. They breathed using book lungs and captured food particles using their coiled whipping appendages. Strombids lived in shallow freshwater environments, such as ponds, lakes, and rivers. The entrance of their cement labium played a key role in sealing off food away from unwanted particles before they reached the mouth.

Strombid fossils have been found in Early Silurian to Early Triassic rocks around the world, indicating they were a cosmopolitan group that existed across various continents. The great abundance of strombid fossils allows paleontologists to study echinodermal body plan in detail and reconstruct events of evolutionary history. Their conservation and crystallization-like properties have been compared to certain living prosobranch snails.

Despite their widespread presence, the largest identifiable fossil specimens of strombids found have usually reached dimensions in the tens of millimeters in length. Despite the constraints of early paleontology methods, strombids remain an enduring source of data for sedimentological reconstructions and the corresponding environments they are from. Further research could uncover fundamental clues to water circulation, near-surface formation, and historical development of existing coastal geology in particular tracts of ancient times.