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

Cascolus ravitis gen. et sp. nov. is a three-dimensionally preserved
fossil crustacean with soft parts from the Herefordshire (Silurian)
Lagerstätte, UK. It is characterized by a head with a head shield and five
limb pairs, and a thorax (pereon) with nine appendage-bearing segments
followed by an apodous abdomen (pleon). All the appendages except the
first are biramous and have a gnathobase. The post-mandibular appendages
are similar one to another, and bear petal-shaped epipods that probably
functioned as a part of the respiratory–circulatory system. Cladistic
analysis resolves the new taxon as a stem-group leptostracan
(Malacostraca). This well-preserved arthropod provides novel insights into
the evolution of appendage morphology, tagmosis and the possible
respiratory–circulatory physiology of a basal malacostracan.