- species arranged by lineage and FAD (time control age-window is: 0-800Ma)
exilis sublineage
Globorotalia pertenuis Like G. exilis but larger and with a distinctly more lobate and compressed test.
Globorotalia exilis Like G. limbata but with a more compressed, thinner, and delicate test.
miocenica sublineage
Globorotalia multicamerata Like G. limbata but with more chambers in final whorl (usually 8-10 vs 6-8), a circular-outline to the test, and a wide, circular and deep umbilicus
Globorotalia miocenica Distinguished from other species of the menardii lineage by its distinctly planoconvex test and circular outline.
Globorotalia pseudomiocenica strongly-biconvex test with a sub-circular equatorial periphery and pronounced keel.
Globorotalia limbata Like G. menardii but uniformly increasing chambers in the final whorl; spiral sutures, initially straight then become sharply curved near the periphery, giving a hockey-stick shape
menardi sublineage
Globorotalia menardii Like G. praemenardii but larger, with raised spiral sutures, and a more massive keel.
Globorotalia praemenardii Like G. archeomenardii but larger, more lobulate, and with less convex spiral side.
Globorotalia archeomenardii Lenticular, low trochospiral, prominent keel and densely perforate surface; aperture low-arched slit, with a distinct lip
Taxonomic discussion: The subgenus Menardella proposed by Bandy (1972) for the Globorotalia praescitula-archeomenardii-praemenardii-menardii evolutionary lineage, which has been, and remains, an important element of Late Neogene planktonic foraminiferal assemblages of tropical to warm-subtropical waters. Species of the Menardella lineage are characterized by lenticular, trochospiral tests, a prominent keel and smooth, densely perforate surfaces (Pl. 28, Figs. 1, The subgenus Globorotalia, which includes the Gr. lenguaensis-Gr. plesiotumida-Gr. tumida lineage, has many characteristics in common with Menardella, but they are phylogenetically unrelated.
Although Globorotalia (G.) praescitula, originally evolved in the temperate areas, it subsequently migrated to the tropics and thence gave rise to Menardella during the late Early Miocene (Text Fig. 14). Although the earliest representative of Menardella (Gr. (M.) archeomenardii) first appeared within Early Miocene Zone N8, the lineage did not become dominant among the tropical globorotaliids until the extinction of Fohsella at 12.4 Ma.
Members of Menardella during the Pliocene and Quaternary exhibit a wide range of variation, especially with respect to the strength of the keel, the number of chambers in the final whorl coiling mode, and bending of the final chamber. [Kennett & Srinivasan 1983]
NB These concise distinguishing features statements are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus. They are being edited as the site is developed and comments on them are especially welcome.
Description
Biogeography and Palaeobiology
Geographic distributionSince Menardella is so distinctly tropical, changes in its relative abundances in stratigraphic sequences have been used extensively as a paleoclimatic tool. [Kennett & Srinivasan 1983]
Geological Range: Last occurrence (top): Extant. Data source: Total of ranges of the species in this database First occurrence (base): within M5b subzone (15.10-16.27Ma, base in Burdigalian stage). Data source: Total of ranges of species in this database
Plot of occurrence data:
Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
Neptune data: this is a higher taxon page so Neptune data is not plotted. For the customisable plot option go to a genus page Parent: Globorotalia
Primary source for this page: Kennett & Srinivasan 1983 p. 120
References:
Bandy, O. L. (1972). Origin and development of Globorotalia (Turborotalia) pachyderma (Ehrenberg). Micropaleontology. 18(3): 294-318. gs
menardii lineage compiled by the pforams@mikrotax project teamviewed: 7-12-2024
/Globorotalia (Globorotalia) cultrata exilis/Blow 1969 pl07 f01-3.JPG)
