Anatomy of the Ordovician Trilobite Placoparia
A recently discovered specimen of Placoparia (Placoparia) cambriensis in shale from Lower Llanvirn rocks of South Wales has the antennae preserved, but more remarkably a partial infilling of the alimentary canal and traces of intersegmental bars and the coxa-body junction. The exoskeleton is reconstructed, including the previously unremarked ridge on the articulating half ring of the thoracic segments and pygidium. Building on earlier ideas and on descriptions of living arthropods, musculature in the extended and fully enrolled positions is suggested, and its operation in enabling the animal's activities.
Philosophical Transactions of the Royal Society of London Series B
- Pub Date:
- January 1993