Hastigerinella digitata Rhumbler 1911 from: Bolli, H.M.Saunders, J.B. (1985): Oligocene to Holocene low latitude planktic foraminifers. In: Plankton Stratigraphy Eds: Bolli, H.M.Saunders, J.B. p. 155-262 | . |
Notice: This catalogue page may contain unedited data.
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Species Hastigerinella digitata Rhumbler 1911 |
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| Discussion / Comments: |
Bolli & Saunders (1985):
The genus definition has gone through two emendations. Originally described by Cushman (1927) as 'test similar to Hastigerina in the young, in the adult, the chambers elongate, club shaped, the spines limited to the outer end of the chambers', it was emended by Banner & Blow (1959) as 'Globorotalia in which the adult chambers become radially elongate, and which possess no carinae'. The same authors emended the genus again in 1960 as 'Hastigerininae (as emended by Banner & Blow, 1959), in which the coiling becomes streptospiral, and in which the chambers become radially elongate, and, in later growth stages, bifurcate or trifurcate to give horn like extensions of the chambers, or at least show potential bifurcation by bifocal concentration of spines distally'. Characteristic for the species is its very large overall test size (holotype 5 ram, excluding spines), streptospiral arrangement of the well separated chambers which become increasingly elongate during ontogeny. The earliest chambers are spherical to ovoid, becoming increasingly elongate and pupoid and eventually broader in apertural view. In adult forms the last chambers divide, forming at least two elongate, club shaped extensions. Long spines, triangular in cross sections, occur at the distal ends of the chambers; they are usually observed only in living specimens. The aperture is a wide, fairly high interiomarginal equatorial arch. Because of the very thin and delicate wall the exceedingly large specimens are very fragile and compared with other planktic species are very rare. It is probably for this reason that Hastigerinella is almost exclusively known only from the Holocene. An exception to this is an occurrence reported by Giannelli, Salvatorini & Sampò (1976) from the Late Miocene of the Piedmont Basin in northern Italy (Fig. 45-2). |
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Bolli & Saunders (1985):
Quilty (1976):
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| References: |
Rhumbler,L. (1911):
Die Foraminiferen (Thalamophoren) der Plankton-Expedition; Part I - Die allgemeinen Organisationsverhältnisse der Foraminiferen . . Ergebnisse der Plankton-Expedition der Humboldt-Stiftung, Kiel & Leipzig Vol. 3 p. 331pp
Quilty,P.G.. (1976):
Planctonic foraminifera DSDP Leg 34- Nazca Plata . DSDP initial reports Vol. 34
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
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