Trilobatus bisphericus

• Main Authors: Bergh, Eugene W., Compton, John S.
• Format: Text
• Language: unknown
• Published: Zenodo 2022
• Subjects: Biodiversity; Taxonomy; Chromista; Foraminifera; Globothalamea; Rotaliida; Globigerinidae; Trilobatus; Trilobatus bisphericus; Heywood; Kennett; Saunders; Todd; Planktonic foraminifera
• Online Access: https://dx.doi.org/10.5281/zenodo.5840590; https://zenodo.org/record/5840590

Trilobatus bisphericus (Todd, 1954) Pl. 8, figs. 1–2 Globigerinoides bisphericus Todd, 1954, p. 681, pl. 1, fig.1; Reed, 1965, p. 83, pl. 15, fig. 1–2; Bolli et al ., 1985, p. 199, pl. 24, fig.8; Kender et al. , 2008, p. 520, pl. 27, figs. 5, 8. Globigerinoides sicanus Kennett & Srinivasan, 1983, p. 62, pl. 13, fig. 4–6. Description : The wall surface is macroperforate and cancellate. The test is rounded and circular in cross section. The three to four chambers in the final whorl are globular in shape. The larger chamber envelops earlier chambers, hiding the umbilicus. The sutures are strongly depressed. Secondary apertures form along deep sutures. Remarks: The relative abundances of T. bisphericus are trace (<1%) in samples of all three cores. The tests are small, measuring 0.3 mm in diameter. Bolli et al. (1985) note Trilobatus trilobus (previously Globigerinoides trilobus ) to be ancestral to T. bisphericus . Environmental preferences: This species is recorded to be adapted to warm waters (Bicchi et al ., 2003), as well as being a cosmopolitan species (BouDagher-Fadel, 2015). Global stratigraphic range: T. bisphericus is an indicator species of the early to middle Miocene – Burdigalian to Langhian (Kennett & Srinivasan, 1983; Bolli et al., 1985; BouDagher-Fadel, 2015). Regional occurrence: This species is recorded to occur in middle Miocene strata in 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 33-34, DOI: 10.11646/zootaxa.5091.1.1, http://zenodo.org/record/5840434 : {"references": ["Todd, R. (1954) Probable occurrence of Oligocene on Saipan. American Journal of Science, 252 (11), 673 - 682. https: // doi. org / 10.2475 / ajs. 252.11.673", "Reed, K. J. (1965) Mid-Tertiary smaller Foraminifera from a bore at Heywood, Victoria, Australia. Bulletins of American Palaeontology, 49, 39 - 104.", "Bolli, H. M., Saunders, J. B. & Perch-Nielsen, K. (1985) Plankton Stratigraphy. Cambridge University Press, Cambridge, 1032 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.", "Kennett, J. P. & Srinivasan, M. S. (1983) Neogene Planktonic Foraminifera. A Phylogenetic Atlas. Hutchinson Ross, Stroudsburg, 265 pp.", "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", "BouDagher-Fadel, M. K. (2015) Biostratigraphic and geological significance of planktonic foraminifera. UCL Press, London, 306 pp. https: // doi. org / 10.2307 / j. ctt 1 g 69 xwk"]}