Use of mathematical methods to determine the ichnofossils species composition

Abstract

SUMMARY The studied specimen from the basal horizon of the Kanivska suite is an agglomeration of phosphatized debris of various types of ichnofauna, cemented with a phosphateous and sand substrate. To our opinion, there are fragments of a kernel decapoda dwelling structures of Thalassinoides Ehrenberg ichnogenus and cores of the burrows of Ophiomorpha Lundgren genus. Thalassinoides Ehrenberg can be inferred from the condition of the surface, absence of a constructed wall and its size. The phosphorite features of the Ophiomorpha Lundgren have a characteristic ophiomorphic sculpture in the form of knobbles on the outer surface. The structures of this type have certain differences in the distribution and nature of phosphate material. The described kernels are interpreted as domus of fossil fauna. They were not known earlier within of the Middle Dniper area. Since the main sign of species diagnosis is kernel’s diameter, we used Akaike criteria to assess the probability of the number of species in a sample. The models consisted of 1 and 2 groups. The result showed that the most probable is the model where the sample consists of 1 group. Computations were performed using the programs tpsDig2 ver. 2.31 and the Old Past ver. 2.17. Keywords: Eocene, Kanivska suite, phosphatized remains, ichnophauna.