A new crustacean from the Herefordshire (Silurian) Lagerstätte, UK, and its significance in malacostracan evolution.

Abstract in brief

• The study describes a newly discovered, well-preserved crustacean fossil from the Silurian period in the UK, which includes soft parts like limbs and internal features, offering a rare glimpse into ancient marine life.
• The fossil has a detailed body structure with a head shield, five limb pairs, a thorax with nine segments, and an unsegmented abdomen, with most appendages being biramous (split into two parts) and equipped with gnathobases, suggesting specialized functions.
• Cladistic analysis classifies this crustacean as a stemgroup leptostracan (an early form of Malacostraca), providing important insights into the evolution of appendages, body segmentation, and respiratory/circulatory systems in early malacostracan arthropods.]