The hermit crab Palaeopagurus vandenengeli from the Lower Cretaceous of Speeton, UK, found in vivo in an ammonite (Fraaije, 2003).
Dr. René H.B. Fraaije
info@oertijdmuseum.nl
Het Oertijdmuseum (Boxtel, The Netherlands)
Friday, 28th of September 2018 (10:45-11:30) at the international symposium “Crustacea Through Time“
Crustaceans (phylum Arthropoda) are a group of invertebrate animals comprising some 50,000 species that are distributed worldwide. Crabs, lobsters, shrimps and isopods are among the best-known crustaceans. Having appeared first during the Early Cambrian period, crustaceans have had ample time to undergo sheer endless experiments with regard to form and function and to play numerous roles, predominantly in aquatic ecosystems.
The basic crustacean body consists of a number of segments, or somites. The body is divided into a cephalothorax (carapace), an abdomen and a tail (telson). Crustaceans are the only arthropods that have two pairs of (joint) appendages (antennules and antennae) in front of the mouth and paired appendages near the mouth that function as jaws.
The largest crustaceans belong to the Decapoda, a large order (of about 10,000 species) that includes the American lobster, which can attain weights of 20 kg, and the giant Japanese spider crab, which has legs that can span up to 3.7 metres. At the other end of the scale, many members of the subclass Copepoda are less than one millimetre in total length.
A new terminology for several carapace regions in hermit crabs will be outlined and hypotheses on the early speciation of hermit crabs are put forward, based on carapace morphology and ecological shifts. The newly discovered co-evolution of bamboo and hermit crabs will be highlighted as well.