Mineralogy of shells from two freshwater snails Belgrandiella fontinalis and B. kuesteri

Unusual Crystal Formation in Organisms - Exceptions that Confirm Biomineralization Rules

“…Fritz et al, (1990) indicated that minerals of elemental composition similar to calcium carbonates could be mineralized by mollusks. Findings of a small amount of dolomite, beside other minerals in the embryos and larvae of the mussels Mytilus edulis (Medaković, 1995) in the embryos, early echinopluteus, and in spines, teeth and skeleton of adult Antarctic Sea urchins Sterechinus neumayeri (Medaković & Popović, 2000;Medaković et al, 2003) confirm the statement of the above authors, and indicate two possible formation mechanisms of dolomite in both Belgrandiella species, as well as SiCa 2 in Zospeum isselianum. We believe that dolomite in both Belgrandiella species is influenced by specific environmental characteristics of the locality at Stn 2.…”

“…Similar deformation effects were seen in the shells of adult oysters C. gigas and European flat oyster Ostrea edulis sampled at several localities along the East Adriatic coast (Medaković, 1995). In our previous research, X-ray powder diffraction (XRD) was used to study calcification and changes in the biomineralization process of the bivalvia and other invertebrates influenced by environmental changes (Medaković et al, 1997(Medaković et al, , 2003. Although mollusk shells are considered to be a powerful tool for monitoring environmental conditions, alterations in the biomineralization processes influenced by TBT have been insufficiently investigated so far.…”

“…X-ray powder diffraction (XRD) was used to study the mineral composition and phase fractions of the shells of freshwater snails Belgrandiella fontinalis (F. Schmidt 1847) and B. kuesteri (Boeters 1970) collected from three springs in north-eastern Slovenia and subterranean snails Zospeum alpestre (Freyer 1855) and Z. isselianum (Pollonera 1886) sampled in four caves in Kamnik -Savinja Alps, Slovenia (Medaković et al, 1999(Medaković et al, , 2003Slapnik & Medaković, 2007). The gastropod shells contain an outer organic periostracum layer and an inner carbonate layer.…”

“…from the Adriatic sea . However, dolomite is registered as a starting biomineral between other unusual biominerals only in the embryos of the bivalve Mytilus edulis, and in the embryos, larvae and adults of the Antarctic sea urchins Sterechinus neumayeri (Medaković, 1995;Medaković et al, 2003). A different approach could be used to explain the presence of dolomite in the organisms.…”

Biomineralization in the Sea Hare Aplysia punctata Initiated by Nano-Dolomite

“…by activity of sulphate or methane reducing and urea decomposing bacteria) in two species of tape worms, in freshwater snails, in pearls, in bladder stones of the Dalmatian dog, in human granulomas, tooth enamel, kidney and urinary stones. Our former research confirmed the formation of dolomite in the shells of the adult freshwater snails Belgrandiella sp., 39 and as a minor component (from traces up to 5 molar %) in calcareous algae Coralina, Lithophyllum and Pseudolithophyllum sp. from the Adriatic sea.…”