Globorotalia crassaformis hessi Bolli & Premoli Silva 1937 (TaxonConcept

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Subspecies Globorotalia crassaformis hessi Bolli & Premoli Silva 1937

Discussion / Comments:

Bolli & Saunders (1985):
Compared with the subspecies crassaformis, hessi is more distinctly quadrangular and less lobate in equatorial view and the spiral surface often appears somewhat concave instead of planar. The last chamber is usually not larger than the penultimate, which is in contrast to the holotype of G. crassaformis crassaformis, where it is distinctly larger. The peripheral margin is rounded and the umbilical portion high and slightly inflated though less so than in oceanica and ronda. The last chamber is often slightly offset obliquely downwards and has an acute peripheral margin or a faint keel. The wall surface is rough as in ronda covered by pustules except for the last chamber which may be more delicate. Hessi is close to ronda but differs from it in the more quadrangular periphery in equatorial view, the slightly concave spiral side and in the above mentioned characters of the last chamber. The spiral view of the Middle Pleistocene specimen figured in Stainforth et al. (1975, fig. 159/5) as G. crassaformis represents a typical G. c rassaformis hessi.

Synonym list:

Bolli & Saunders (1985):

1973 Globorotalia hessi Bolli & Silva. - Premoli Silva & Bolli : (=Globorotalia crassaformis 'B' Bolli, 1970,p. 580, pl.4, fig.13, holotype, figs.15,16, partypes)

1985 Globorotalia crassaformis hessi Bolli & Premoli Silva. - Bolli & Saunders : p.237 figs. 37.10; 6,10,11

Stratigraphy - absolute ages:

FAD: 0.75 ± 0 [Ma], Berggren et al. (1995)

References:

Premoli Silva,I. and Bolli,H.M. (1973):
Late Cretaceous to Eocene planktonic foraminifera and stratigraphy of Legs 15 sites in the Carribean Sea.
In: Initial Reports of the Deep Sea Drilling Program Vol. 15 p. 449-547

Bolli,H.M. and Saunders,J.B. (1985):
Oligocene to Holocene low latitude planktic foraminifers.
In: Plankton Stratigraphy Eds: Bolli, H.M.Saunders, J.B. p. 155-262

Berggren,W.A.; Hilgen,F.J.; Langereis,C.G.; Kent,D.V.; Obradovich,J.D.; Raffi,I.; Raymo,M.E. and Shackleton,N.J. (1995):
Late Neogene chronology: New perspectives in high-resolution stratigraphy . Geological Society of America Bulletin Vol. 107(11)

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