The suggested system of foraminifera (higher taxa)

The system proposed for foraminifera (higher taxa) is based on the investigations by Rauser-Chernousova & Fursenko; Mikhalevich; Maslakova; Saidova; on the classification by Loeblich & Tappan [7] and the works by the present author with changes and additions. To substantiate establishing the higher taxa - 15 subclasses and subordinate orders in the class Foraminifera d'Orbigny, 1826, the present author used jointly several criteria established first by Fursenko and Podobina. The chemical composition, the structure of walls and tests are of fundamental importance. Besides the morphological characters, the geochronological, paleogeographical and paleobiogeographical criteria were applied in describing all studied taxa. The occurrence of the established subclasses based on orders in the Phanerozoic was adopted from «The Fundamentals of Paleontology» with regard to recent data. The accompanying scheme (Fig.) demonstrates clearly five prominent stages in the development of foraminifera depending on the tectonic movement manifestation. The first stage covers three subclasses, two of them, Allogromiata and Astrorhiziata, seem to emerge since the final Precambrian, and the third subclass, Ammodisciata, since the beginning of the Cambrian. They existed during the Phanerozoic with the progressive complication of subordinate taxa. The author has studied some ammodiscide tests and established three superfamilies in this order. At present, the ammodiscide rank has been upgraded to a subclass with distinguishing three orders, viz. Ammodiscida, Haplophragmiida and Lituolida. The second stage in the foraminifer development, of which the prime representatives seem to emerge since the final Ordovician and Silurian, concerns subclasses Lagenata, Textulariata, Ataxophragmiata, Orbitolinata, Fusulinata, and Miliolata. Some of them reached their acme in the Carboniferous and Permian, and became extinct by the final Paleozoic (Fusulinata) and final Paleogene (Orbitolinata). The third stage involves the development of 4 subclasses, viz. Rzehakiniata, Rotaliata, Globigerinata, and Buliminata. The representatives of these subclasses emerged in the Triassic and are now existent. The fourth stage includes the emergence of two subclasses Spirillinata and Nummulitiata, and the extinction of Lituolida; the fifth stage is the extinction of Orbitolinata and Nummulitiata by the final Eocene. The established five stages of the foraminifer development coincide principally with the final phases of the tectogenesis: the first stage: the emergence of subclasses 1-3; the end of the Baikalian epoch of tectogenesis; the second stage: the emergence of subclasses 2-7; the end of the Caledonian epoch; the third stage: the emergence of subclasses 8-11; the end of the Hercynian folding epoch; the fourth stage: the emergence of subclasses 12, 13; the end of the Kimmerian folding epoch; the fifth stage: the emergence of new Globogerinida taxa and the extinction of subclasses 5 and 13; the prominent part of the Alpine folding epoch. It should be noted that the emergence of new taxa coincides with these tectonic or geochronological events. In the paper, the description of 15 subclasses and subordinate orders of foraminifera is presented.

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