. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. BIOMINERALIZATION IN CAUDOFOVEATA 227. Figure 2. Energy dispersive X-ray analysis spectrum representing the elemental composition of the axial plate (A) and denticle (B) ot Falcideiis sp. The same elements are present in both structures. The .v axis represents X-ray energies in kiloelectron volts. The y axis represents counts per second (arbitrary scale tor qualitative comparison). The cop- per peak comes from the grid bar. of mineralization, ranging from immature teeth (con- taining only soft organic structures) to fully mi
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. BIOMINERALIZATION IN CAUDOFOVEATA 227. Figure 2. Energy dispersive X-ray analysis spectrum representing the elemental composition of the axial plate (A) and denticle (B) ot Falcideiis sp. The same elements are present in both structures. The .v axis represents X-ray energies in kiloelectron volts. The y axis represents counts per second (arbitrary scale tor qualitative comparison). The cop- per peak comes from the grid bar. of mineralization, ranging from immature teeth (con- taining only soft organic structures) to fully mineralized mature teeth (Kirschvink and Lowenstam. 1979; Lowen- stam and Weiner, 1985; Mann et 1986). Most of these animals are herbivorous scrapers (Steneck and Watling. 1982) whose teeth are abraded and broken during feeding (Webb et al. 1989) and are continuously replaced (Webb et al, 1990). The Chaetodermatidae. however, are selec- tive carnivores (Scheltema, 1981), and their denticles, axial plate, and lateral membrane persist throughout their life span (Luitfried von Salvini-Plawen. pers. comm.). Since these structures are not renewed, it seems that a continuous process of mineralization does not occur, in contrast to chitons (Kirschvink and Lowenstam, 1979) and limpets (Mann et al. 1986). Impregnation of the denticles of Falcidens sp. with a crystalline phosphorous mineral, hydroxyapatite, consti- tutes an unusual example of mineralization in inverte- brates. The great majority of invertebrates exhibit calcium phosphates only in the amorphous state (Taylor and Sim- kiss, 1994). Among the invertebrate structures reported to have crystalline phosphorous minerals (apatite) are the radular teeth of the Polyplacophora (Lowenstam, 1967), the shells of inarticulate brachiopods (LeGeros et al. 1985), and the shell plates of certain barnacles (Lowens- tam et 1992). The presence of amorphous iron oxide as a final product of mineralization in the denticles and axial plate
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