Globoturborotalita euapertura


Classification: pf_cenozoic -> Globigerinidae -> Globoturborotalita -> Globoturborotalita euapertura
Sister taxa: G. tenella, G. rubescens, G. decoraperta, G. apertura, G. connecta, G. druryi, G. nepenthes, G. woodi, G. cancellata, G. occlusa, G. paracancellata, G. pseudopraebulloides, G. barbula, G. bassriverensis, G. brazieri, G. eolabiacrassata, G. euapertura, G. gnaucki, G. labiacrassata, G. martini, G. ouachitaensis, G. sp.,

Taxonomy

Citation: Globoturborotalita euapertura (Jenkins, 1960)
Rank: species
Basionym: Globigerina euapertura Jenkins, 1960
Synonyms:
Taxonomic discussion:

The taxonomic affinity of Globoturborotalita euapertura has long been debated. Many authors have considered this form to be homeomorphic with Dentoglobigerina prasaepis (Blow) or related to Turborotalia ampliapertura (Bolli), while others have referred it to the original genus designation Globigerina (Stott and Kennett, 1990; Huber, 1991; Huber and Quillévéré, 2005). Jenkins (1960) considered his new species to be intermediate between Globigerina venezuelana and Globigerina ampliapertura. Dentoglobigerina prasaepis was considered to be a junior synonym of G. euapertura by Jenkins and Orr (1972) and Fleisher (1975). However, inspection of SEM images of the holotype and our new material, indicates the taxon has a cancellate test that differs from the wall structure of Dentoglobigerina or Turborotalia. We therefore conclude that euapertura belongs to Globoturborotalita, and is unrelated to Turborotalia ampliapertura and species of Dentoglobigerina as previously suggested. This refined diagnosis is consistent with Huber and Quillévéré’s (2005) concept of this species as used to define the upper Oligocene “Globigerina euapertura Highest-occurrence Zone” (Zone AO4). Jenkins (1960) reports an increase in the size of G. euapertura specimens in the younger part of the range but this has not been verified by morphometric studies elsewhere. [Spezzaferri et al. 2018]

Catalog entries: Globigerina euapertura

Type images:

Distinguishing features:

4 wedge-like chambers in the final whorl, last chamber reniform; aperture broad & low, confined to the umbilicus; sutures deeply incised.

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


Diagnostic characters:

Globoturborotalita euapertura has four chambers in the final whorl with the aperture confined to the umbilicus and located over the second chamber. It is distinguished by its deeply incised sutures, broad, low arched aperture and wedge like chambers. The final chamber has a distinctive reniform shape. It differs from Dentoglobigerina prasaepis by its wall texture and chamber shape and from D. venezuelana by its generally smaller size, more lobulate outline, lack of a tooth/lip and looser coiling mode. It is distinguished from Turborotalia ampliapertura by its umbilical, low arched aperture, rather than extraumbilical, high arched aperture and sacculifer-type wall texture. [Spezzaferri et al. 2018]


Wall type: Normal perforate, spinose, sacculifer-type wall texture, an average of about 20 pores/50 μm2 test surface area.

Test morphology: Low trochospiral, medium sized test, consisting of 3 whorls, weakly lobulate in outline, 4 subglobular, slightly embracing chambers in the last whorl, increasing slowly in size, sutures incised, straight to slightly curved on both sides; low arched umbilical aperture, bordered by a thin, indistinct rim; final chamber reniform in shape, directly over the umbilicus; in edge view chambers ovoid in shape, ultimate chamber extends over the umbilicus, oval to subcircular in outline. [Spezzaferri et al. 2018]

Size: Holotype maximum diameter 0.30 mm. [Spezzaferri et al. 2018]

Character matrix

test outline:Lobatechamber arrangement:Trochospiraledge view:Concavo-convexaperture:Umbilical
sp chamber shape:Globularcoiling axis:Lowperiphery:N/Aaperture border:Thin lip
umb chbr shape:Subtriangularumbilicus:Wideperiph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:Weakly depressedumb depth:Deepwall texture:Cancellateshell porosity:Macroperforate: >2.5µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:4.0-4.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: More common in colder water high southern latitude environments, though it has been recorded in subtropical sites (Premoli Silva and Boersma, 1988). [Spezzaferri et al. 2018]

Isotope paleobiology: Poore and Matthews (1984) suggest an intermediate (thermocline) dwelling habitat for G. euapertura, however they find inconsistent results and acknowledge that more than one morphospecies may have been analyzed. The specimens analyzed by Wade and Pearson (2008) are now considered to be Dentoglobigerina prasaepis. [Spezzaferri et al. 2018]

Phylogenetic relations: It probably evolved from G. woodi by developing a more rounded periphery, a lower, wider arched aperture and more wedge like chambers. [Spezzaferri et al. 2018]

Most likely ancestor: Globoturborotalita woodi - at confidence level 3 (out of 5). Data source: Spezzaferri et al. 2018.

Biostratigraphic distribution

Geological Range:
Notes: Not currently well constrained. This species has been recorded from the upper Eocene through lower Miocene (e.g., Leckie and others, 1993), though it has frequently been confused with D. venezuelana and D. prasaepis. It is considered valuable in mid- to high southern latitudes. Jenkins (1965) erected the G. euapertura Zone from the ‘mid’ Oligocene to lower Miocene, a concept that has been carried over in recent high southern latitude biozonation schemes (Stott and Kennett, 1990; Berggren, 1992a,b; Huber and Quillévéré, 2005). Spezzaferri and Premoli Silva (1991) record a lowest occurrence in mid- Subzone P21a, Huber and Quillévéré (2005) record this species from lower to middle Zone AO1.

Berggren (1992b) constrain the LAD at the Kerguelen Plateau to Chron C6Cn.2n (23.8 Ma), close to the Oligocene/Miocene boundary. However, Globoturborotalita euapertura has frequently been recorded from lower Miocene sediments and was indeed described from the lower Miocene.

[Spezzaferri et al. 2018]
Last occurrence (top): within M1b subzone (21.12-22.44Ma, top in Aquitanian stage). Data source: Spezzaferri et al. 2018 f8.1
First occurrence (base): within O4 zone (28.09-29.18Ma, base in Rupelian stage). Data source: Spezzaferri et al. 2018 f8.1

Plot of occurrence data:

Primary source for this page: Spezzaferri et al. 2018 - Olig Atlas chap.8 p.244

References:

Berggren, W. A. (1992). Paleogene planktonic foraminifer magnetobiostratigraphy of the southern Kerguelen Plateau (sites 747-749). Proceedings of the Ocean Drilling Program, Scientific Results. 551-568. gs

Chaisson, W. P. & Leckie, R. M. (1993). High-resolution Neogene planktonic foraminifer biostratigraphy of Site 806, Ontong Java Plateau (Western Equatorial Pacific). Proceedings of the Ocean Drilling Program, Scientific Results. 130: 137-178. gs

Fleisher, R. (1975). Oligocene planktonic foraminiferal biostratigraphy, central North Pacific Ocean, DSDP Leg 32. Initial Reports of the Deep Sea Drilling Project. 32: 753-763. gs

Hooyberghs, H. J. F. & de Meuter, F. (1972). Biostratigraphy and inter-regional correlation of the Miocene deposits of Northern Belgium based on planktonic foraminifera; the Oligocene-Miocene boundary on the southern edge of the North Sea basin, Brussels. Koninklijke Vlaamse Academie voor Wetenschappen, Letteren en Schone Kunsten van België.. -. gs

Huber, B. T. & Quillévéré, F. (2005). Revised Paleogene planktic foraminiferal biozonation for the Austral Realm. Journal of Foraminiferal Research. 35: 299-314. gs

Huber, B. T. (1991c). Paleogene and Early Neogene Planktonic Foraminifer Biostratigraphy of Sites 738 and 744, Kerguelen Plateau (Southern Indian Ocean). Proceedings of the Ocean Drilling Program, Scientific Results. 119: 427-449. gs

Jenkins, D. G. & Orr, W. N. (1972). Planktonic foraminiferal biostratigraphy of the east equatorial Pacific--DSDP Leg 9. Initial Reports of the Deep Sea Drilling Project. 9: 1059-1193. gs

Jenkins, D. G. (1960). Planktonic foraminifera from the Lakes Entrance oil shaft, Victoria, Australia. Micropaleontology. 6: 345-371. gs

Jenkins, D. G. (1965b). Planktonic Foraminiferal zones and new taxa from the Danian to lower Miocene of New Zealand. New Zealand Journal of Geology and Geophysics. 8(6): 1088-1126. gs

Leckie, R. M., Farnham, C. & Schmidt, M. G. (1993). Oligocene planktonic foraminifer biostratigraphy of Hole 803D (Ontong Java Plateau) and Hole 628A (Little Bahama Bank), and comparison with the southern high latitudes. Proceedings of the Ocean Drilling Program, Scientific Results. 130: 113-136. gs

Li, Q., McGowran, B. & Brunner, C. A. (2003a). Neogene planktonic foraminiferal biostratigraphy of Sites 1126, 1128, 1130, 1132, and 1134, ODP Leg 182, Great Australian Bight. Proceedings of the Ocean Drilling Program, Scientific Results. 182: 1-67. gs

Li, Q., Jian, Z. & Su, X. (2005). Late Oligocene rapid transformations in the South China Sea. Marine Micropaleontology. 54: 5-25. gs

Loubere, P. (1985). Population diversity of planktonic foraminifers and stable isotope record across the Eocene/Oligocene boundary: Hole 549A. Initial Reports of the Deep Sea Drilling Project. 80: 557-566. gs

Poore, R. Z. & Matthews, R. K. (1984). Oxygen isotope ranking of late Eocene and Oligocene planktonic foraminifers: implications for Oligocene sea-surface temperatures and global ice-volume. Marine Micropaleontology. 9: 111-134. gs

Poore, R. Z. (1984). Middle Eocene through Quaternary planktonic foraminifers from the southern Angola Basin: Deep Sea Drilling Project Leg 73,. Initial Reports of the Deep Sea Drilling Project. 73: 429-448. gs

Premoli Silva, I. & Boersma, A. (1988). Atlantic Eocene planktonic foraminiferal historical biogeography and paleohydrographic indices. Palaeogeography, Palaeoclimatology, Palaeoecology. 67: 315-356. gs

Spezzaferri, S. & Premoli Silva, I. (1991). Oligocene planktonic foraminiferal biostratigraphy and paleoclimatic interpretation from Hole 538A, DSDP Leg 77, Gulf of Mexico. Palaeogeography, Palaeoclimatology, Palaeoecology. 83: 217-263. gs

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

Spezzaferri, S., Olsson, R. K., Hemleben, C., Wade, B. S. & Coxall, H. K. (2018c). Taxonomy, biostratigraphy, and phylogeny of Oligocene and Lower Miocene Globoturborotalita. 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 8): 231-268. gs

Stott, L. D. & Kennett, J. P. (1990). The Paleoceanographic and Paleoclimatic signature of the Cretaceous/Paleogene boundary in the Antarctic: Stable isotopic results from ODP Leg 113. Proceedings of the Ocean Drilling Program, Scientific Results. 113: 829-848. gs

Wade, B. S. & Pearson, P. N. (2008). Planktonic foraminiferal turnover, diversity fluctuations and geochemical signals across the Eocene/Oligocene boundary in Tanzania. Marine Micropaleontology. 68: 244-255. gs


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Globoturborotalita euapertura compiled by the pforams@mikrotax project team viewed: 17-10-2019

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