Taxonomy and Species Features

Abstract

Following the convention of Murray (1897) we distinguish between spinose and non-spinose species. Parker (1962) was the first who used this criterion for purposes of classification. The categories were refined by incorporating data on shell wall ultrastructure obtained by transmission electron microscopic (TEM) investigations (e.g. Bé et al., 1966; Takay-anagi et al., 1968). After the scanning electron microscope was introduced to geological science in 1967, the three-dimensional microstructural and ultrastructural features of the shell were studied with renewed vigor. Thus the importance of spines and pustules became obvious (e.g. Lipps, 1966; Hemleben, 1969a,b; Scott, 1974b; Hemleben, 1975; Saito et al., 1976; Benjamim and Reiss, 1979; Cifelli, 1982). Further progress was made when the reproductive sequence in spinose species was documented, including clarification of the origin of residual spine base holes remaining in the shell after spine shedding prior to gametogenesis. These fine shell features, together with our ontogenetic studies, allow us to classify the modern planktonic foraminifers in a somewhat different way.