Encrinurus

Encrinurus is a genus of extinct trilobites belonging to the order Phacopida and the family Encrinuridae. These marine arthropods lived during the Silurian period, approximately 443 to 419 million years ago. Fossils of Encrinurus have been found in various parts of the world, indicating a widespread distribution across ancient oceans.

These trilobites are characterized by a distinctive cephalon (head shield) and pygidium (tail shield). The cephalon often features a prominent, raised glabella, which is the central lobe of the head. A notable feature of many Encrinurus species is the presence of three or more spines on the posterior edge of the pygidium, which are often long and slender. The thorax, located between the cephalon and pygidium, was segmented. Their exoskeleton was generally robust.

Encrinurus likely inhabited shallow marine environments, potentially on the seafloor, where they may have scavenged for food or filtered small particles from the sediment. Their exact ecological role is still a subject of study, but their morphology suggests they were benthic organisms. The genus Encrinurus is important for biostratigraphy, helping to date rock layers from the Silurian period due to its widespread occurrence and distinctive features. Numerous species have been described within the genus, reflecting variations in size, spine development, and other morphological details across different fossil localities.