ORIGINAL ARTICLE Comparative 3D microanatomy and histology of the eyes and central nervous systems in coleoid cephalopod hatchlings Elvira Wild & Tim Wollesen & Gerhard Haszprunar & Martin Heß Received: 6 November 2012 /Accepted: 16 June 2014 # Gesellschaft für Biologische Systematik 2014 Abstract Adaptive radiation of an animal group is the evo- lutionary variation of morphology, physiology, and behavior opening up new habitats and resources. An impressive exam- ple of the reciprocal interdependency of form and function is found in the anatomy of cephalopod visual and central ner- vous systems. Interspecific differences of sensory organs and signal processing structures reflect the eco-functional context, e.g., the species-specific demands emanating from habitat and foraging behavior. To substantiate this, we investigated the eyes and brain neuropils of early post-hatching stages of six coleoid cephalopod species (Sepia officinalis, Rossia macrosoma, Sepietta obscura, Idiosepius notoides, Loligo vulgaris, and Octopus vulgaris), showing different size and inhabiting different ethoecological niches. Comprehensive 3D structure data sets were produced in light microscopic resolu- tion, i.e., semithin section series of the head region (histology presented for I. notoides, R. macrosoma, and S. obscura for the first time) and 3D surface renderings of the neuropils, enabling the display of all components in arbitrary perspectives and combinations, and comparative volumetic anaylsis of homolo- gous lobe neuropils. Differing in absolute size considerably, the visual and central nervous systems of the six species follow the same bauplan in adult-like configuration. The visual sense obviously is of paramount importance already after hatching, but also, equilibrioception and olfaction are well developed. The species-specific shapes of various components show that some plasticity and distinct differences in volumetric ratios are found, subject to their functional relevance and to different demands of the lifestyle on the brachial and swimming motor function, on camouflage, as well as on sensoric and cognitive abilities. Keywords Functional morphology . Volumetry . Animal vision . 3D-rendering . Interactive model Introduction Since the Cuvier-Geoffroy debate in 1830, the intrinsic mutual conditionality of structure and function is accepted as a basic biological principle (see e.g., Lauder 1981; Boletzky et al. 1997), which not least legitimates research on the functional morphology of visual systems (e.g., Lythgoe 1979; Archer et al. 1999). Hence, by means of morphology, valid concep- tions about functional aspects of the visual system, as well as the peripheral and central nervous system (CNS), can be found. Eye size, photoreceptor length, and photoreceptor density, for instance, have effects on both acuity and sensitivity (see e.g., Warrant and Locket 2004). Several comparative studies on animal eyes conclusively demon- strate the adaptive plasticity and functional relevance of these structures (Cephalopoda, e.g., Scharpf et al. 2008; Makino and Miyazaki 2010; Vertebrata, e.g., Collin and Elvira Wild and Martin Heß contributed equally to this work. Electronic supplementary material The online version of this article (doi:10.1007/s13127-014-0184-4) contains supplementary material, which is available to authorized users. E. Wild : G. Haszprunar : M. Heß (*) BioZentrum LMU, Großhaderner Straße 2-4, 82152 Planegg-Martinsried, Germany e-mail: hess@bio.lmu.de G. Haszprunar Zoologische Staatssammlung München, Münchhausenstraße 21, 81247 München, Germany G. Haszprunar : M. Heß GeoBioCenter LMU, Richard-Wagner-Straße 10, 80333 München, Germany T. Wollesen Integrative Zoologie, Universität Wien, Althanstraße 14, 1090 Wien, Austria Org Divers Evol DOI 10.1007/s13127-014-0184-4