Daughter taxa (time control age-window is: 0-800Ma)![]() | ||||
Streptochilus latum Rapidly expanding test, with smooth wall and aperture | ||||
Streptochilus subglobigerum Wall finely perforate and finely cancellate, becoming smooth in the later chambers. | ||||
Streptochilus inglei Smooth walled with a lobulate periphery and straight sutures | ||||
Streptochilus macdougallae Wall cancellate sometimes with coarse pores; test laterally compressed last two chambers slightly sub-inflated. Sutures oblique. | ||||
Oligo-Miocene Species | ||||
Streptochilus cetacense Triangular in shape and flared | ||||
Streptochilus mascarenense Like S. cetacensis but more laterally compressed, more lobulate and pores smaller. | ||||
Streptochilus pristinum Test with straight lateral profile in early portion of the test followed inflation of the later chambers | ||||
Streptochilus rockallkiddense Parallel-sided / rectilinear, often becomes staggered uniserial, ornament variable, aperture may be obscured | ||||
Streptochilus tasmanense Test narrows towards apertural end, occasionally flared, laterally compressed, surface ornamentation of scattered circular pore mounds. | ||||
Paleogene Species | ||||
![]() | ![]() | Streptochilus martini Gradually to moderately tapering test without surface ornamentation | ||
Streptochilus sp. Specimens which cannot be assigned to established species |
Catalog entries: Streptochilus
Distinguishing features:
Parent taxon (Benthic origins): Biserial (separate evolutionary origin)
This taxon: Like Chiloguembelina but with an internal plate connecting successive chambers, a prominent extension of an apertural collar, and a smoother surface texture.
Emended description:
Morphology:
Wall type:
Size:
Geographic distribution: Within the Early Miocene Streptochilus is often abundant in the eastern Atlantic and western indian Oceans at paleo water depths of 1000-2500m - the "High Abundance of Bolivinid (HAB) event" - see Smart & Thomas (2006 - with references to earlier work). Neptune records are predominantly from low-latitudes [editor's comment - JRY 2018]
Isotope paleobiology: Streptochilus globulosum indicate intermediate values for oxygen and carbon stable isotope values, suggestive of a thermocline-dwelling habitat (Resig and Kroopnick, 1983). No data available for Eocene taxa.
[Huber et al. 2006]
Phylogenetic relations: It is possible that the distribution of Streptochilus spp. represents one or more expatriation events from the coastal benthos to the pelagic zone (Darling and others, 2009), in addition to lack of observation of these small taxa, explaining its intermittent temporal distribution in the fossil record. Furthermore, it is likely that either no or not all species traditionally placed in the genus Streptochilus are descended from the genus Chiloguembelina. The name Streptochilus is used for planktonic species which morphologically cannot be distinguished from species in the benthic genus Bolivina. The genus, therefore, is polyphyletic, including potentially different clades. At present, however, we do not have enough information on evolutionary patterns to identify clades of biserial planktonic species, and it is proposed, therefore, that the name Streptochilus be retained provisionally until evolutionary relations are understood. [Smart & Thomas 2018]
Most likely ancestor: Benthic foraminifera - at confidence level 2 (out of 5). Data source: Smart & Thomas 2018.
See also: Chiloguembelinidae - family in which it was previously classified;
Geological Range:
Notes: Middle Eocene (Zone E10) to Recent; intermittent. [Smart & Thomas 2018]
Last occurrence (top): near top of Gelasian Stage (91% up, 1.9Ma, in Gelasian stage). Data source: Total of range of species in this database
First occurrence (base): in upper part of Lutetian Stage (69% up, 43.2Ma, in Lutetian stage). Data source: Total of range of species in this database
Plot of occurrence data:
Primary source for this page: Huber et al. 2006 - Eocene Atlas, chap. 16, p. 476; Smart & Thomas 2018 p.498; Kennett & Srinivasan 1983, p.21
Brönnimann, P. & Resig, J. (1971). A Neogene globigerinacean biochronologic time-scale of the southwestern Pacific. Initial Reports of the Deep Sea Drilling Project. 7(2): 1235-1469. gs V O Cushman, J. A. (1933d). Some new Recent foraminifera from the Tropical Pacific. Contributions from the Cushman Laboratory for Foraminiferal Research. 9(4): 77-95. gs V O Cushman, J. A. (1933c). Some new foraminiferal genera. Contributions from the Cushman Laboratory for Foraminiferal Research. 9(2): 32-38. gs V O Darling, K. F., Thomas, E., Kasemann, S. A., Seears, H. A., Smart, C. W. & Wade, C. M. (2009). Surviving mass extinction by bridging the benthic/planktic divide. Proceedings of the National Academy of Sciences, USA. 106: 12629-12633. gs Huber, B. T., Olsson, R. K. & Pearson, P. N. (2006). Taxonomy, biostratigraphy, and phylogeny of Eocene microperforate planktonic foraminifera (Jenkinsina, Cassigerinelloita, Chiloguembelina, Streptochilus, Zeauvigerina, Tenuitella, and Cassigerinella) and Problematica (Dipsidripella). In, Pearson, P. N., Olsson, R. K., Hemleben, C., Huber, B. T. & Berggren, W. A. (eds) Atlas of Eocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication. 41(Chap 16): 461-508. gs V O Kennett, J. P. & Srinivasan, M. S. (1983). Neogene Planktonic Foraminifera. Hutchinson Ross Publishing Co., Stroudsburg, Pennsylvania. 1-265. gs Kierstead, C. H., Leidy, R., Fleisher, R. L. & Boersma, A. (1969). Neogene zonation of tropical Pacific cores. In, Brönnimann, P. & Renz, H. H. (eds) Proceedings of the First International Conference on Planktonic Microfossils, Geneva, 1967. Brill, Leiden 328-338. gs Loeblich, A. R. & Tappan, H. (1988). Foraminiferal Genera and Their Classification (Volume I-II). Van Nostrand Reinhold Co., New York. 1-1059. gs Poore, R. Z. & Gosnell, L. B. (1985). Apertural features and surface texture of upper Paleogene biserial planktonic foraminifers: Links between Chiloguembelina and Streptochilus. Journal of Foraminiferal Research. 15: 1-5. gs Resig, J. M. & Kroopnick, P. M. (1983). Isotopic and distributional evidence of a planktonic habit for the foraminiferal genus Streptochilus Bronnimann and Resig, 1971. Marine Micropaleontology. 8(3): 235-248. gs Smart, C. W. & Thomas, E. (2006). The enigma of early Miocene biserial planktic foraminifera. Geology. 34: 1041-1044. gs Smart, C. W. & Thomas, E. (2007). Emendation of the genus Streptochilus Brönnimann and Resig 1971 (Foraminifera) and new species from the lower Miocene of the Atlantic and Indian Oceans. Micropaleontology. 53(1-2): 73-103, 103 figures, 113 lates, 101 table. gs Smart, C. W. & Thomas, E. (2018). Taxonomy, biostratigraphy, and phylogeny of Oligocene Streptochilus. 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 19): 495-511. gs V OReferences:
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Streptochilus compiled by the pforams@mikrotax project team viewed: 25-5-2022
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