[en] Mantis shrimps (or Stomatopods) form one of the most surprising crustacean order in earth. Separated from decapods since Cretacean, species composing this group display unique features that makes them formidable marine benthic predators. In these features can be found the widest visual spectrum, a transformed telson used both as a shield and as a fin, an antennal pallet used as a rudder but also a pair of enhanced predatorial limbs. Two kinds of predatorial limbs exists, dividing mantis shrimps in two groups: smashing limbs used to brake carapaces and to knock out preys and spearing limbs used to impale fishes. Both these limbs are deployed at high speed thanks to their ability to store and release elastic energy and are reinforced to endure impacts. This study will focus on one spearing mantis shrimp, the striped mantis shrimp (Lysiosquillina maculata (Fabritius,1973)) and the cuticle of its raptorial appendage. The main goal is to understand how spines found in this appendage are internally arranged to face the mechanical stress that occurs when harpooning prey. Techniques as optical microscopy and scanning electron microscopy will allow to define how is arranged the cuticle found in the spine. Techniques of micro-analysis will then superimpose composition to the structural information. These analyses highlight a complex assembly of four layers which can’t be directly linked to the classic succession of layers found in arthropods (e.g. endocuticle, exocuticle and epicuticle). These layers were named lamellar layer, parallel layer, soft helicoidal layer and highly mineralised layer. Each of them differs by fibres orientations, mineralisation rate or compositions and they are thought to play precise roles in the mechanical behaviour of the stomatopod spine.
Research center :
CAREM - Cellule d'Appui à la Recherche et à l'Enseignement en Microscopie - ULiège FOCUS - Freshwater and OCeanic science Unit of reSearch - ULiège
