A new crustacean from the Herefordshire (Silurian) Lagerstätte, UK, and its significance in malacostracan evolution.
Cascolus ravitisgen. 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.
Department of Geology, University of Leicester, Leicester LE1 7RH, UK djs@leicester.ac.uk.
David J
http://orcid.org/0000-0002-1716-5819
DJ
Siveter
Department of Geology and Geophysics, and Yale Peabody Museum of Natural History, Yale University, PO Box 208109, New Haven, CT 06520-8109, USA.
Derek E G
DE
Briggs
Earth Collections, University Museum of Natural History, Oxford OX1 3PW, UK.|Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK.
Derek J
DJ
Siveter
Department of Earth Sciences and Engineering, Imperial College London, London SW7 2BP, UK.
Mark D
MD
Sutton
Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK.
David
D
Legg
D000818:Animals; D003445:Crustacea; D005580:Fossils; D006257:Head; D010802:Phylogeny; D006113:United Kingdom
Crustacea; Herefordshire Lagerstätte; Leptostraca; Malacostraca; Phyllocarida; Silurian