This page provides data from the catalog of type descriptions. The catalog is sorted alphabetically. Use the current identification link to go back to the main database.
Current identification/main database link: Tenuitella Fleisher, 1974, emended Li, 1987
Tenuitella n. gen. is proposed to include a closely related group of small Cenozoic forms which are usually referred to either Globorotalia or Turborotalia, but which are unrelated to species of either genus. The primary diagnostic characteristic common to all species placed in Tenuitella is a microperforate surface wall texture. The wall in these forms consists of a smooth surface penetrated by extremely small perforations, approximately 0.5μ in diameter. Small pustules or crystallites are commonly present on the wall surface and may obscure the perforations. In some specimens, these pustules may be so common as to completely cover the fundamentally smooth surface, but in other forms the pustules may be rare or absent. The microperforate wall of Tenuitella spp. typically appears smooth and thin, but in specimens with major pustule development it seems slightly roughened. In well-preserved tests, it may appear translucent. All known species have a minute to small test, an umbilical to extraumbilical or peripheral aperture flanked by a narrow lip or rim, and a rounded periphery lacking a distinct carina. Chambers are arranged in a low trochospiral coil, but in some species (e.g., T. gemma) occasional specimens tend to become pseudoplanispiral.
Extra details from original publication
Tenuitella can be differentiated from almost all other Cenozoic globorotaloid genera by the nature of the wall. The microperforate wall texture is quite different from the relatively smooth wall with large but optically indistinct pores of Globorotalia and the cancellate wall of Turborotalia. These species are differentiated from Acarinina spp. and Morozovella spp. by the absence of large, coarse pseudospines. Testacarinata Jenkins is a distinct but short-lived carinate offshoot of Tenuitella. Globigerinita is a primarily Neogene genus that evolved from Tenuitella in the Late Oligocene and is distinguished by the primarily umbilical aperture and the common presence of a bulla.
The purely morphological differences between Tenuitella and Globanomalina are more difficult to define. In general, species of the latter genus have more compressed and less inflated and distinct chambers than those in Tenuitella, and the wall of Globanomalina appears to be more coarsely perforate. The fundamental basis for recognizing Tenuitella, however, is the common and independent phyletic history of the species included in it, a separate phylogeny of which the distinctive wall texture is the primary reflection. The forms included in Globanomalina and Tenuitella have been evolutionarily separate since at least the early Middle Eocene and probably since the basal Tertiary.
In addition to the species discussed below (T. gemma, T. anfracta, T. clemenciae), a number of other species should apparently be included in this genus on the basis of published descriptions. These are:
Tenuitella compiled by the pforams@mikrotax project team viewed: 29-9-2020
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