Abstracts - Deutsche Zoologische Gesellschaft

Morphology Symposium 69O MO.9 (Mo) - ENMorphology and ultrastructure of the placenta of Atelerix albiventris, the middleAfrican, white-bellied hedgehogSwetlana Siniza, Ulrich ZellerLehrstuhl für Spezielle Zoologie, Museum für Naturkunde, Humboldt-Universität zu BerlinUntil now there has been only one reliable description of chorioallantoic placentation in Erinaceidae,published by Hubrecht in 1889. In order to contribute to the reconstruction of the placental morphotypeof Laurasiatheria, we studied the near term placenta of a single female Atelerix albiventris usinglight and transmission electron microscopy. Atelerix albiventris has a discoid, definitive chorioallantoicplacenta, which is situated in an antimesometrial position. The late placental disc consists ofa labyrinthine zone at the fetal side, underlain by cytotrophoblastic tissue and a broad basal maternallayer of decidua, which contains clusters of secretory active uterine glands. The labyrinth is formedby the fetal allantochorion, building up a network of cytotrophoblast-bordered lacunae, throughwhich the maternal blood flows, thus confirming the haemochorial nature of the interhaemal barrier.Products of maternal erythrocyte and tissue breakdown are visible in the uterine lumen, though nospecialized haemo- or heterophagous region, as described in other Eulipotyphla, could be found. Theplacenta of Atelerix albiventris resembles this of Erinaceus europeus, previously described by Hubrecht.Within Laurasiatheria the compact and invasive mode of placentation, found in Erinaceidae,as well as in other Eulipotyphla, Chiroptera and Carnivora is plesiomorphic and always correlatedwith an altricial neonate.O MO.10 (Mo) - ENComparative morphology of the hemolymph vascular system in scorpions – a surveyusing corrosion casting, microCT, and 3D-reconstructionChristian S. Wirkner 1 , Lorenzo Prendini 21Allgemeine & Spezielle Zoologie, Universität Rostock; 2 American Museum of Natural History,New York, USAIn a recent paper (Wirkner & Prendini 2007; Journal of Morphology 268:401–413) we presented thefirst comprehensive investigation of the gross morphology of the scorpion vascular system, based ona survey of 27 species representing all major lineages of the order, using classical and modern nondestructivetechniques in combination with three-dimensional reconstruction. The presentation summarizesthe main results of the investigation: The hemolymph vascular system (HVS) of Scorpionescomprises a central pumping heart which extends the entire length of the mesosoma and is enclosedin a pericardium. Several arteries branch off the heart to supply different organs and body regions.Two different anterior aorta major branching patterns are identified among the species investigated.Arteries that branch off the anterior aorta system supply the appendages (chelicerae, pedipalps andwalking legs) and the central nerve mass with a complex arterial network. This study of the HVS ofscorpions provides further evidence that the vascular systems of euarthropods can be highly complex.Use of the term “open circulatory system” within euarthropods is re-emphasized, as it refers tothe general organization of the body cavity rather than to the complexity of the circulatory system.