Daughter taxa (time control age-window is: 0-800Ma) | ||||
 |  |  | Protentelloides dalhousiei Like P. primitivus but with more evolute, near-planispiral coiling; apertural system, more variable and complex, with tendency to become ‘cribrate’. | |
 |  |  | Protentelloides primitivus Large, laterally compressed, low trochospiral/pseudoplanispiral, 4-6 chambers in the final whorl, final chamber reduced and bulla-like, sutures depressed, straight to curved; aperture an elongated slit at the base of the bulla-like final chamber. | |
| Protentelloides sp. | ||||
Taxonomic discussion: The appearance of this short ranging genus (1-2 million years) in the upper Oligocene is a prominent event in the evolution of this group. It may have biostratigraphic potential, however to date, Protentelloides has not been recorded outside its type location in the eastern equatorial Atlantic Ocean, Sierra Leone Rise, DSDP Hole 366A (Zhang and Scott, 1995) and ODP Hole 667A (Spezzaferri, 1994). Zhang and Scott (1995) suggested that Protentelloides dalhousiei maybe the ancestor of Clavatorella bermudezi. It is easy to see the morphological resemblance but a direct connection to C. bermudezi seems unlikely since that taxon does not appear until the early Miocene, approximately 7 million years after the Protentelloides horizon, and intermediates between Globorotaloides hexagonus and C. bermudezi have been described (Pearson, 1995). We suggest Protentelloides dalhousiei represents a sub-clavate homeomorph of C. bermudezi. [Coxall & Spezzaferri 2018]
Catalog entries: Protentelloides
Distinguishing features:
Parent taxon (Globigerinidae): Wall spinose, usually with 3½-6 globular chambers in final whorl, trochospiral or planispiral
This taxon: Laterally compressed, often with bulla/bullate final chamber
Wall type: Normal perforate, coarsely cancellate, sacculifer-type to ruber/sacculifer-type. Possibly spinose. [Coxall & Spezzaferri 2018]
Morphology: Laterally compressed, low trochospiral/pseudoplanispiral; lobate to strongly lobate, 5-7 chambers in the final whorl, increasing rapidly in size; chambers flatten towards the center of the test; sutures on both sides almost radial, depressed, straight, becoming curved to sigmoidal; final chamber is typically reduced in size, bulla-like, centered at the equatorial margin and highly variable in morphology, ranging from globular and protruding to flattened and unobtrusive; primary aperture highly variable, also equatorially centered, ranging from a low extraumbilical to equatorial, symmetrical or asymmetrical arch, a long equatorial slit extending up the final chamber face, a bi-radiate equatorial arch (with one ray extending into the umbilical region). The aperture is bordered by an imperforate flap-like lip that may fuse to subdivide the primary aperture, or be perforated by one or more circular or elongated accessory apertures, reminiscent of the ‘cribrate’ supplementary aperture system of late Eocene Cribrohantkenina. [Coxall & Spezzaferri 2018]
Most likely ancestor: Globorotaloides - at confidence level 3 (out of 5). Data source: Coxall & Spezzaferri 2018 f4.1.
Geological Range:
Last occurrence (top): in mid part of Aquitanian Stage (48% up, 21.8Ma, in Aquitanian stage). Data source: Total of range of species in this database
First occurrence (base): in upper part of Chattian Stage (61% up, 25Ma, in Chattian stage). Data source: Total of range of species in this database
Plot of occurrence data:
Primary source for this page: Coxall & Spezzaferri 2018 - Olig Atlas chap.4 p.115
Coxall, H. K. & Spezzaferri, S. (2018). Taxonomy, biostratigraphy, and phylogeny of Oligocene Catapsydrax, Globorotaloides, and Protentelloides. In, Wade, B. S., Olsson, R. K., Pearson, P. N., Huber, B. T. & Berggren, W. A. (eds) Atlas of Oligocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication. 46(Chap 4): 79-124. gs V O Pearson, P. N. (1995). Planktonic foraminifer biostratigraphy and the development of pelagic caps on guyots in the Marshall Islands group. Proceedings of the Ocean Drilling Program, Scientific Results. 144: 21-59. gs V O Spezzaferri, S. (1994). Planktonic foraminiferal biostratigraphy and taxonomy of the Oligocene and lower Miocene in the oceanic record. An overview. Palaeontographia Italica. 81: 1-187. gs Zhang, J. & Scott, D. B. (1995). New planktonic foraminiferal genus and species from the upper Oligocene, DSDP Hole 366A, Leg 41. Micropaleontology. 41(1): 77-83. gsReferences:
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Protentelloides compiled by the pforams@mikrotax project team viewed: 22-10-2021
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