Globorotaloides testarugosus


Classification: pf_cenozoic -> Globigerinidae -> Globorotaloides -> Globorotaloides testarugosus
Sister taxa: G. atlanticus, G. stainforthi, G. eovariabilis, G. hexagonus, G. quadrocameratus, G. suteri, G. testarugosus, G. variabilis, G. sp.,

Taxonomy

Citation: Globorotaloides testarugosus (Jenkins, 1960)
Rank: species
Basionym: Globorotalia testarugosa Jenkins, 1960
Synonyms:
Taxonomic discussion:

We change the species name to its masculine form to accord with Article 31.2 of the ICZN (“a species-group name, if it is or ends in a Latin or latinized adjective or participle in the nominative singular, must agree in gender with the generic name with which it is at any time combined”). Thus Globorotaloides testarugosa becomes G. testarugosus. We recognize Globorotaloides testarugosus as a distinct morphotype with angular chambers and a highly rugose wall that occurs in the mid-Oligocene to lower Miocene. Importantly our concept of the taxon has been broadened to encompass Globorotalia extans Jenkins, 1960, which was described at the same time from the same locality (Lakes Entrance Oil Shaft). According to Jenkins, testarugosus s.s. is restricted to Jenkins’ local “pre- Globoquadrina dehiscens dehiscens zone”, while the extans morphotype extends stratigraphically above testarugosus into the “Globoquadrina dehiscens dehiscens” and “Globigerina woodi” zones (Jenkins, 1993). These zones are approximately equivalent to Zones O6-M3 of Wade and others (2011). [Coxall & Spezzaferri 2018]

According to Jenkins (1960), G. extans differs from G. testarugosus by being more loosely coiled and in the greater degree of chamber inflation. He recognized two variants; i) extans ‘megalospheric forms’, having a relatively large proloculus and 4 chambers in the final whorl, and (ii) extans ‘microspheric forms’, which has a relatively small proloculus, 5 chambers in the final whorl and extends stratigraphically above the megalospheric forms. Micro- and megalospheric forms are not generally recognized in the planktonic foraminifera, so these morphotypes likely belong to different species. The ‘megalospheric’ form (and holotype of extans) we refer to G. testarugosus (Pl. 4.11, Fig. 15), such that extans becomes a junior synonym of testarugosus. The ‘microspheric’ form, which is represented by the paratype of extans, we here assign to Globorotaloides hexagonus (Pl. 4.6, Figs. 9, 10). Technically extans should be the senior synonym because it has page priority. However, we chose to retain G. testarugosus as the working name because of the confusion with the micro- and megalospheric type examples of extans, and since the concept of G. testarugosus is better known and used. [Coxall & Spezzaferri 2018]

Jenkins (1971) reported a high degree of variability in populations of G. testarugosus from the New Zealand Whaingaroan type sample (N55/545), with some specimens having a bulla-like final chamber. Forms described as Globorotaloides aff. G. testarugosus (Jenkins) from the subantarctic Atlantic and Indian Oceans by Stott and Kennett (1990; Huber, 1991) we suggest are closer to G. eovariabilis (and synonymized as such). Although not commonly recorded outside of the Austral realm, G. testarugosus has been described from Trinidad (Pearson and Wade, 2009) and Tanzania (Stewart and others, 2004, figured as Globorotaloides sp.), suggesting a global, geographic range. [Coxall & Spezzaferri 2018]

Catalog entries: Globorotalia testarugosa;

Type images:

Distinguishing features: Differs from other species of Globorotaloides by the more compact coiling, less lobate peripheral outline, a highly rugose wall, more restricted umbilicus and distinctly straight sutures.

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:

Differs from other species of Globorotaloides by the more compact coiling, less lobate peripheral outline, a highly rugose wall, more restricted umbilicus and distinctly straight sutures, which are grooved on the umbilical side and tangential on the spiral side. [Coxall & Spezzaferri 2018]


Wall type: Nonspinose (?). Normal perforate, coarsely cancellate, sacculifer-type wall texture, with a distinctly honeycomb appearance.

Test morphology: Test outline compact, continuous equatorial periphery very slightly quadrilobate, axial periphery rounded; 3-3½ whorls of inflated chambers, arranged in a trochospire, flattened on the spiral side; 11-12 chambers in adult tests, 4½-6 in the final whorl increasing moderately in size; umbilicus shallow to moderately deep and narrow; umbilical sutures, straight, radial, depressed and somewhat grooved, spiral sutures initially indistinct, later depressed, distinctly straight, tangential; spiral aperture a low interiomarginal umbilical-extraumbilical arch surrounded by a narrow lip. [Coxall & Spezzaferri 2018]

Size: Holotype maximum diameter 0.3 mm. [Coxall & Spezzaferri 2018]

Character matrix

test outline:Subcircularchamber arrangement:Trochospiraledge view:Planoconvexaperture:Umbilical-extraumbilical
sp chamber shape:Globularcoiling axis:Lowperiphery:N/Aaperture border:Thin lip
umb chbr shape:Subtriangularumbilicus:Narrowperiph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:Weakly depressedumb depth:Shallowwall texture:Cancellateshell porosity:Macroperforate: >2.5µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:4.0-5.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Tropical to subtropical. Possibly global. Most common in the Austral realm (southeastern Australia and New Zealand; Jenkins, 1960, 1975) as well as the southeastern Atlantic, South Pacific and Indian Oceans (Premoli Silva and Spezzaferri, 1990; Spezzaferri, 1994; Stewart and others, 2004). [Coxall & Spezzaferri 2018]

Isotope paleobiology: Aze et al. 2011 ecogroup 4 - Open ocean sub-thermocline. Based on very light δ13C and very heavy δ18O. Sources cited by Aze et al. 2011 (appendix S3): Keller (1985) [Coxall & Spezzaferri 2018]

Phylogenetic relations: Globorotaloides testarugosus probably evolved from Globorotaloides eovariabilis in the mid-Oligocene. [Coxall & Spezzaferri 2018]

Most likely ancestor: Globorotaloides eovariabilis - at confidence level 3 (out of 5). Data source: Coxall & Spezzaferri 2018.

Biostratigraphic distribution

Geological Range:
Notes: Based on the originally reported stratigraphic range of G. testarugosus and G. extans ‘megalospheric’ (Jenkins, 1960), in combination with records of this taxon from elsewhere we report the range of G. testarugosus as mid-Oligocene Subzone P21a (O3/O4) (Premoli Silva and Spezzaferri, 1990; Spezzaferri, 1994) to lower Miocene Zone N4 (O7/M1) (Spezzaferri, 1994). [Coxall & Spezzaferri 2018]
Last occurrence (top): within M1 zone (21.12-22.96Ma, top in Aquitanian stage). Data source: Coxall & Spezzaferri 2018
First occurrence (base): within O5 zone (26.93-28.09Ma, base in Chattian stage). Data source: Coxall & Spezzaferri 2018

Plot of occurrence data:

Primary source for this page: Coxall & Spezzaferri 2018 - Olig Atlas chap.4 p.111

References:

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: 79-125. 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. (1960). Planktonic foraminifera from the Lakes Entrance oil shaft, Victoria, Australia. Micropaleontology. 6: 345-371. gs

Jenkins, D. G. (1971). New Zealand Cenozoic Planktonic Foraminifera. New Zealand Geological Survey, Paleontological Bulletin. 42: 1-278. gs

Jenkins, D. G. (1985). Southern mid-latitude Paleocene to Holocene planktic foraminifera. In, Bolli, H. M. , Saunders, J. B. & Perch-Nielsen, K. (eds) Plankton Stratigraphy. Cambridge University Press, Cambridge 263-282. gs

Jenkins, D. G. (1993). Cenozoic southern mid- and high latitude biostratigraphy and chronostratigraphy based on planktonic foraminifera. In, Kennett, J. P. & Warnke, D. A. (eds) The Antarctic Paleoenvironment: A Perspective on Global Change, Part 2. Antartic Research Series. 60: -. gs

Pearson, P. N. & Wade, B. S. (2009). Taxonomy and stable isotope paleoecology of well-preserved planktonic foraminifera from the uppermost Oligocene of Trinidad. Journal of Foraminiferal Research. 39: 191-217. gs

Premoli Silva, I. & Spezzaferri, S. (1990). Paleogene planktonic foraminifer biostratigraphy and paleoenvironmental remarks on paleogene sediments from Indian Ocean sites, Leg 115. Proceedings of the Ocean Drilling Program, Scientific Results. 115: 277-314. 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

Stewart, D. R. M. , Pearson, P. N., Ditchfield, P. W. & Singano, J. M. (2004). Miocene tropical Indian Ocean temperatures: evidence from three exceptionally preserved foraminiferal assemblages from Tanzania. Journal of African Earth Sciences. 40: 173-190. 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., Berggren, W. A. & Pälike, H. (2011). Review and revision of Cenozoic tropical planktonic foraminiferal biostratigraphy and calibration to the geomagnetic polarity and astronomical time scale. Earth-Science Reviews. 104: 111-142. gs


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Globorotaloides testarugosus compiled by the pforams@mikrotax project team viewed: 26-6-2019

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