Improving the parameterization of stromatoporoid shapes – a detailed approach to stromatoporoid morphometry

Eight specimens of Devonian stromatoporoids with well visible latilaminae arrangement exposed on polished slabs were subjected to a detailed morphometric analysis. The studies have revealed that the so far used stromatoporoid parameterization method leaves a broad field of uncertainty concerning the exact definitions of particular parameters. The possible ways of making the measurements and the propositions of more precise definitions of the parameters used in the method, both of the growth form above the sea bottom and of the whole skeleton are therefore presented in this paper. The B_m - basal length of the skeleton, has been defined as a straight line joining the two ends of the basal surface, which have been pointed basing on the stromatoporoid's overall shape, latilaminae arrangement and angular relation to the main growth axis position in ontogenetical development, length. The B_n - basal length of the growth form above the sea bottom, is to be measured along a straight line joining the ends of the last visible latilamina. From among a number of possible definitions of the V_m - vertical height of the whole skeleton, a straight line joining the initial growth nucleus and the highest point on the specimen's surface above the B_m line has been selected. The V_n - vertical height of the growth form above the sea bottom is defined as the height of the point on the stromatoporoid surface highest above the B_n measured perpendicularly to it. A parameter of burial ratio, BR=(V_m-V_n)/V_m, is introduced.