Globigerinella obesa

• Main Authors: Bergh, Eugene W., Compton, John S.
• Format: Text
• Language: unknown
• Published: Zenodo 2022
• Subjects: Biodiversity; Taxonomy; Chromista; Foraminifera; Globothalamea; Rotaliida; Globigerinidae; Globigerinella; Globigerinella obesa; Kennett; Saunders; Planktonic foraminifera
• Online Access: https://dx.doi.org/10.5281/zenodo.5840585; https://zenodo.org/record/5840585

Globigerinella obesa (Bolli, 1957) Pl. 7, figs. 9–10 Globorotalia obesa Bolli, 1957, p. 119, pl. 29, figs 2–3. Globigerina praebulloides Blow, 1959, pl. 8, fig. 47; Kender, 2007, p. 202, pl. 49, fig. 7. Globigerinella obesa Bolli et al. , 1985, p. 206, fig. 26.44; Kennett & Srinivasan, 1983, p. 234, pl. 59, figs 2–5; Kender et al ., 2008, p. 202, pl. 29, fig. 4; Spezzaferri et al., 2018a, p. 198, pl. 6.1, figs. 14–17; pl. 6.8, figs. 1–23. Description : The wall surface is cancellate-spinose. The test is trochospirally arranged with the chambers globular in shape, which rapidly enlarge towards the terminal end. Four chambers are visible in the final whorl in umbilical view, with straight depressed sutures. The test is biconvex in marginal view and has a lobate outline in umbilical view.A thin imperforate lip may border the apertural arch. The aperture extends from the umbilical to extra-umbilical region, forming an arched shape visible in the peripheral margin view. Remarks: The relative abundance of G. obesa in this study is trace (<1%) in samples of all three cores. The tests are relatively moderate in size, measuring up to 0.5 mm in diameter. G. obesa is ancestral to Globigerinella siphonifera , which later gave rise to Globigerinella calida . This species evolved from G. archaeobulloides and is different from that species in its aperture, which is more umbilical to extraumbilical towards the margin of the test. It also differs from G. bulloides in this way and has a more inflated terminal chamber compared to its initial chambers. G. obesa is different from G. praesiphonifera in having four chambers in the last whorl, whereas G. praesiphonifera has five (Spezzaferri et al ., 2018a). Globigerina praebulloides is synonymised and now accepted as G. obesa . Environmental preferences: G. obesa has been identified as a warm to temperate species (Bicchi et al ., 2003). Global stratigraphic range: G. obesa has been recorded in Oligocene to lower Pliocene strata (Kennett & Srinivasan, 1983). Regional occurrence: This species has been recorded to occur in middle Miocene strata from the Congo Basin (Kender et al ., 2008) to the northern Namibian outer continental shelf, south of the Kunene River mouth (this study). : Published as part of Bergh, Eugene W. & Compton, John S., 2022, Taxonomy of Middle Miocene foraminifera from the northern Namibian continental shelf, pp. 1-55 in Zootaxa 5091 (1) on pages 32-33, DOI: 10.11646/zootaxa.5091.1.1, http://zenodo.org/record/5840434 : {"references": ["Blow, W. H. (1959) Age, correlation and biostratigraphy of the upper Tocuto (San Lorenzo) and Pozon formations, eastern Falcon, Venezuela. Bulletins of American Paleontology, 39, 67 - 215.", "Kender, S. (2007) Foraminiferal characterisation and taxonomy of Oligocene Miocene Congo Fan deep sea sub-environments, offshore Angola. Ph. D. thesis, University College, London, 325 pp.", "Bolli, H. M., Saunders, J. B. & Perch-Nielsen, K. (1985) Plankton Stratigraphy. Cambridge University Press, Cambridge, 1032 pp.", "Kennett, J. P. & Srinivasan, M. S. (1983) Neogene Planktonic Foraminifera. A Phylogenetic Atlas. Hutchinson Ross, Stroudsburg, 265 pp.", "Kender, S., Kaminski, M. A. & Jones, R. W. (2008) Early to middle Miocene foraminifera from the deep-sea Congo Fan, offshore Angola. Micropalaeontology, 54, 477 - 568.", "Spezzaferri, S., Coxall, H. K., Olsson, R. K., Hemleben, C. & Wade, B. (2018 a) Taxonomy, biostratigraphy, and phylogeny of Oligocene Globigerina, Globigerinella, and Quiltyella n. gen. Cushman Foundation for Foraminiferal Research, Special Publication, 46, 179 - 214.", "Bicchi, E., Ferrero, E. & Gonera, M. (2003) Palaeoclimatic interpretation based on Middle Miocene planktonic Foraminifera: the Silesia Basin (Paratethys) and Monferrato (Tethys) records. Palaeogeography, Palaeoclimatology, Palaeoecology, 196, 265 - 303. https: // doi. org / 10.1016 / S 0031 - 0182 (03) 00368 - 7"]}