exticus

Exticus is a fictional genus of extinct marine arthropods used here as an example in a hypothetical encyclopedia article. The genus Exticus is typically placed within the informal grouping of early malacostracan crustaceans, with a single described species, Exticus marinus. The temporal range is the Late Devonian to Early Carboniferous, approximately 370 to 320 million years ago, based on the fictional fossil record in this article. Fossils attributed to Exticus have been reported from laminated shales of what is now Central Europe, representing shallow coastal environments.

Morphology: Exticus is characterized by a wedge-shaped cephalon, a segmented thorax with a series of short and robust walking legs, and a broad, shield-like carapace. It measured about 2 to 3 cm in length. The tail region featured a tapering abdomen and small uropods. Appendages suggest a predatory or scavenging lifestyle with frontal gnathobases.

Ecology: Inferred ecology indicates a benthic lifestyle on soft substrates, preying on small invertebrates and detritus. It coexisted with early fishes and other crustaceans and contributed to the diversity of Devonian marine ecosystems.

Discovery and etymology: The name Exticus is coined for this genus, with the species epithet marinus reflecting its marine habitat. The taxonomy and dating are described for illustrative purposes in this fictional context.