Evolutionary morphology of the brain in Peracarida (Crustacea)
Martin E. J. Stegner, Stefan Richter, Christian S. Wirkner
Zoologisches Institut, Universität Rostock
Within Malacostraca, morphological studies of the brain have mainly focussed on decapods. Analyses of other malacostracans are sparse. In this first comparative study of the taxa Mictacea, Spelaeogriphacea, Tanaidacea, Cumacea, Isopoda and Amphipoda - including mancoid Peracarida - the brain of representative species was investigated. Based on semi-thin sections, computerized 3D-reconstructions of the brains and their components were carried out. The brain of each species displays numerous structures which are also present in decapods such as a central body neuropil, olfactory lobes with glomeruli and a lateral and a median protocerebrum. However, the size and position of single neuropils or the origin of nerves leaving the brain may differ considerably within the studied species. Other brain structures such as the optic neuropils are only present in some species. The presented data are discussed from both phylogenetic and evolutionary points of view.