PENETRATION OF MOLLUSCAN AND NON-MOLLUSCAN MINERALS BY THE BORING GASTROPOD UROSALPINX CINEREA

¹ College of Marine Studies, University of Delaware, Lewes, Delaware 19958

1. Results of an experimental study of the capacity of Urosalpinx cinerea follyensis Baker to penetrate 15 kinds of molluscan and abiogenic minerals are reported. Minerals, cut into small wafers, and radular teeth were exposed to penetration by normally boring snails in valve models. Depth of incomplete boreholes was measured with a compound microscope. Extent of dissolution was examined with a scanning electron microscope. All biogenically formed calcareous minerals, except radulae of U. cinerea, and some abiogenic minerals, were penetrated. Rate of penetration of wafers decreased in the following order: calcite and aragonite (shell of Crassostrea virginica, Spisula solidissima, Anomia simplex), strontianite, bone and tooth hydroxyapatite, anhydrite, witherite, and magnesite. Abiogenic minerals siderite, smithsonite, alunite, fluorite, and quartz were not penetrated. Of the 15 tests performed on biogenically formed calcareous minerals, only two snails (or 13%) left the sample on the model before the experiment was terminated; of the 25 tests on abiogenically formed minerals, 20 snails (80%) crawled off the sample before the end of the tests. Experiments demonstrated that Ca, Sr, Ba, and Mg, as carbonates, and Ca both as the phosphate and sulfate, were attacked by the secretion. Fe and Zn, as the carbonates, Ca as the fluoride, Si as the oxide, and K and Al as the sulfate were unaffected.

2. Degree of penetration of beef bone was intermediate between that of shell and human teeth. Dentine was penetrated more deeply than enamel. The core of enamel prisms was dissolved more deeply than the outer region by the secretion. Radular teeth of U. cinerea were unaffected by the secretion during exposures ranging from 0.5 to 2.5 hr.

3. The capacity of U. cinerea to penetrate a wide range of types of minerals explains, in part, the large number of different species upon which it can prey.