Tropidocoryphaceans

Tropidocoryphaceans are an extinct infraorder of trilobites. They are characterized by a prominent, often carinate (ridged) axial furrow and a holaspid pygidium that is typically large and subquadrate to semicircular in shape. The glabella is usually narrow and parallel-sided or slightly tapering. The pleural furrows are well-defined, and the pleurae are often spinose.

These trilobites lived during the Devonian period. Their fossils are found in marine sedimentary rocks of this age. Tropidocoryphaceans are important index fossils, meaning their presence and evolutionary changes can be used to date rock layers.

The group is part of the order Phacopida, which is a diverse and well-studied order of trilobites. Within Phacopida, Tropidocoryphacea is distinguished by its specific pygidial and glabellar features. Fossil specimens of tropidocoryphaceans are often well-preserved, allowing for detailed study of their morphology and paleoecology.

Classification within Tropidocoryphacea has been subject to revision over time as new discoveries are made and analytical techniques improve. However, key genera like Tropidocoryphe are well-established. Their distribution in the fossil record indicates they inhabited a range of marine environments.