Differences in the Young modulus and hardness reflect different functions of teeth within the taenioglossan radula of gastropods

Not just scratching the surface: Distinct radular motion patterns in Mollusca

“…The radular movement is quite complex in all three dimensions: in 1981 Morris and Hickman addressed this topic by artificially protruding gastropod radulae from dead specimens. In this context, it must be highlighted that due to bending and stretching of the membrane, teeth of many taxa do not act as individual and independent structures on the ingesta, but rely on each other, transmitting and distributing forces and stresses from one tooth to another during feeding ( Solem, 1972 ; Morris and Hickman, 1981 ; Hickman, 1984 ; Padilla, 2003 ; Herrera et al, 2015 ; Montroni et al, 2019 ; Krings et al, 2019b ). Hence, the interaction of individual teeth in the radula is quite complex (see Padilla, 2003 ) and in order to get a hold on the morphological diversity of radulae and connect this with possible functional adaptations, the detailed movement of the radula and the interaction of the teeth with the ingesta/substrate, including orientation, rotations or twists, must be documented.…”

Feeding Experiments on Vittina Turrita (Mollusca, Gastropoda, Neritidae) Reveal Tooth Contact Areas and Bent Radular Shape During Foraging

“…The worn teeth from gastropods, sheltered on both rougher sandpapers, rather show fractures and spalling, which also indicates that teeth seem to be cushioned to a certain extent. Either a exible tooth embedment in the radular membrane allows a spreading of teeth to the sides [see also 39,[51][52] and/or a softer cushioning beneath the membrane and embedded teeth in combination with the mechanical behavior of the odontophoral cartilages allows a swerving in dorsal direction, when teeth hit larger asperities [4,6,[53][54][55][56]. Similar mechanisms have been observed for the anchorage of mammalian teeth [e.g.…”

“…This is well supported by their morphology: the inner marginal teeth possess a thicker and shorter stylus, whereas the outer marginal teeth are rather thin and slender. Thus, the inner marginal teeth are potentially rather capable of exerting higher forces than the outer marginal teeth [for the relationship between radular tooth morphology and function see also 39,52,71,73]. Chemical analyses of the radula of the neritid Nerita atramentosa, documenting that the medial marginal teeth are composed of more minerals than the outer ones [70], additionally support this hypothesis.…”

“…The 15 inner marginal teeth have contact areas to the substrate with their cusps and styli as it is proven by the wear on both parts. However, marginal teeth are probably not used for puncturing, since they are exible, but rather for brushing [see also 72] across the substrate and collecting particles by their denticles [for the relationship between hardness and capability of scratching see 15,39,52,71,73]. The hypothesis that neritinomorph marginal teeth are rather used for collecting particles due to their softness and exibility, whereas both lateral teeth are rather used for loosening ingesta from surfaces had been put forward previously [44,72,74] and is well supported by the result of the present study.…”

Depth-Sensing Indentation as a Micro- and Nanomechanical Approach to Characterisation of Mechanical Properties of Soft, Biological, and Biomimetic Materials

“…Therefore, straightforward application of the OP approach may lead to certain inaccuracies in estimations of the reduced contact modulus E * . Previously, we tested properties of insect adhesive structures [11], insect joints [12], insect cuticle [45,46], snake skin [47,48], gecko setae [49], human teeth [50], mollusk teeth [51], and plant materials [45] using nanoindentation by either Berkovich indenter or AFM tip. However, from practical point of view, the use of nominally sharp indenters sometimes may not be desired, e.g., due to the destructive nature of such a method.…”