The sensorial function of the girdle of the Polyplacophora

Abstract

Event Abstract Back to Event The sensorial function of the girdle of the Polyplacophora Carmen Salas1*, Antonio Checa2 and Michael Vendrasco2 1 University of Málaga, Biología Animal, Spain 2 Universidad de Granada, Departamento de Estratigrafía y Paleontología, Spain The polyplacophorans or chitons are characterized by the presence of eight dorsal overlapping shell plates that are embedded in a thick mantle tissue and surrounded by the girdle (also called perinotum). In chitons, the hard layers of plates consist of the uppermost tegmentum, the articulamentum whose projections form the sutural laminae and insertion plates, and the underlying hypostracum. The tegmentum, which is the visible layer of the chiton shell in life, is infiltrated with a complex, tissue-filled canal system that opens at the dorsal valve surface as sensory or secretory organs known as aesthetes. Structures secreted by the epidermis of the girdle have been mainly described as ornamentation or armature, such as numerous calcareous spines, scales, hairs or bristles, but other studies suggest that the girdle epidermis has other functions such as sensorial (Leise and Cloney, 1982; Leise, 1988). In chitons, epidermal sensory receptors have been mainly found around the mouth, on the subradular organ, in the buccal cavity, in the pallial grooves and in the shell. During a study of the formation of the cuticle in the mantle girdle of several species of chitons (Lepidozona pectinulata, Ischnochiton rissoi, Lepidochitona cinerea, Leptochiton algesirensis, Lepidopleurus cajetanus), we have observed several sensory structures in the mantle girdle. In the case of fully-grown scales and marginal spines, a group of cells differentiated from the papilla constitutes a stalked body or nodule, which progressively elevates and pushes the spine until it finally, pierces through the cuticle surface. The stalked nodules are more conspicuous in L. cinerea and L. pectinulata than in L. cajetanus. These projections arise from epidermal papillae and have been considered mechanoreceptors. Lens-like structures have been observed inside some stalked nodules in L. cinerea and L. algesirensis. The stalked nodules show dendritic structures underlying the lens-like structure, which point to a photoreception ability. The lens-like structure found in the nodule of L. cinerea seems to be a rigid, possibly mineralized structure. Aragonite lenses have been found in Acanthopleura granulata by Speiser et al. (2011). In L. algesirensis we have observed groups of long microvilli in the top margin of the papillae and in contact with the spines that we consider as mechanoreceptors. As in other chitons, dendritic processes are frequently found in association mainly with dorsal spicules, although not every spine is innervated. References Leise, E.M. (1988). Sensory organs in the hairy girdles of some mopaliid chitons. Amer. Malacol. Bull., 6:141-151 Leise, E.M. and Cloney R.A. (1982). Chiton integument: ultrastructure of the sensory hairs of Mopalia muscosa (Mollusca: Polyplacophora). Cell Tissue Res., 223: 43-59. Speiser, D.I., Eernisse, D.J. and Johnsen, S. (2011). A chiton uses aragonite lenses to form images. Curr. Biol., 21(8), 665-670. Keywords: chitons, sensory organ, Mechanoreceptors, Biomineralization, aragonite Conference: XIX Iberian Symposium on Marine Biology Studies, Porto, Portugal, 5 Sep - 9 Sep, 2016. Presentation Type: Poster Presentation Topic: 1. ECOLOGY, BIODIVERSITY AND VULNERABLE ECOSYSTEMS Citation: Salas C, Checa A and Vendrasco M (2016). The sensorial function of the girdle of the Polyplacophora. Front. Mar. Sci. Conference Abstract: XIX Iberian Symposium on Marine Biology Studies. doi: 10.3389/conf.FMARS.2016.05.00150 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 30 Apr 2016; Published Online: 03 Sep 2016. * Correspondence: Ms. Carmen Salas, University of Málaga, Biología Animal, Malaga, Malaga, 29071, Spain, casanova@uma.es Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Carmen Salas Antonio Checa Michael Vendrasco Google Carmen Salas Antonio Checa Michael Vendrasco Google Scholar Carmen Salas Antonio Checa Michael Vendrasco PubMed Carmen Salas Antonio Checa Michael Vendrasco Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.