title: New insights into the complex architecture of siliceous copepod teeth.
abstract: Copepods belong to the dominant marine zooplankton taxa and play an important role in particle and energy fluxes of the marine water column. Their mandibular gnathobases possess tooth-like structures, so-called teeth. In species feeding on large proportions of diatoms these teeth often contain silica, which is very probably the result of a coevolution with the siliceous diatom frustules. Detailed knowledge of the morphology and composition of the siliceous teeth is essential for understanding their functioning and their significance in the context of feeding interactions between copepods and diatoms. Based on analyses of the gnathobases of the Antarctic copepod Rhincalanus gigas, the present study clearly shows, for the first time, that the silica in the siliceous teeth features large proportions of crystalline silica that is consistent with the mineral α-cristobalite and is doped with aluminium. The siliceous structures have internal chitinous fibre networks, which are assumed to serve as scaffolds during the silicification process. The compact siliceous teeth of R. gigas are accompanied by structures with large proportions of the elastic protein resilin, likely reducing the mechanical damage of the teeth when the copepods feed on diatoms with very stable frustules. The results indicate that the coevolution with diatom frustules has resulted in gnathobases exhibiting highly sophisticated composite structures.
authors.affiliation: Department of Functional Morphology and Biomechanics, Institute of Zoology, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, D-24118 Kiel, Germany; Biological Oceanography, GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, D-24105 Kiel, Germany. Electronic address: jmichels@zoologie.uni-kiel.de.
authors.forename: Jan
authors.initials: J
authors.lastname: Michels
authors.affiliation: Faculty of Physics and Earth Sciences, Universität Leipzig, Linnéstraße 5, D-04103 Leipzig, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Vogt
authors.affiliation: Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, D-01187 Dresden, Germany.
authors.forename: Paul
authors.initials: P
authors.lastname: Simon
authors.affiliation: Department of Functional Morphology and Biomechanics, Institute of Zoology, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, D-24118 Kiel, Germany.
authors.forename: Stanislav N
authors.initials: SN
authors.lastname: Gorb
mesh_terms: D000818:Animals; D033342:Copepoda / Q000648:ultrastructure*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D012822:Silicon Dioxide; D014070:Tooth / Q000648:ultrastructure
chemical_list: D012822:Silicon Dioxide
keywords: Chitin fibre network; Crystalline silica; Mandibular gnathobase; Marine copepod; Resilin