Streptochilus pristinum


Classification: pf_cenozoic -> Benthic origins -> Streptochilus -> Streptochilus pristinum
Sister taxa: S. globulosum, S. globigerum, S. latum, S. subglobigerum, S. inglei, S. macdougallae, S. cetacense, S. mascarenense, S. pristinum, S. rockallkiddense, S. tasmanense, S. martini, S. sp.,

Taxonomy

Citation: Streptochilus pristinum Brönnimann and Resig, 1971
Rank: species
Synonyms:
Taxonomic discussion:

de Klasz and others (1989) called it, incorrectly, S. pristinus. The name Streptochilus is derived from streptos, Greek for ‘twisted’ and cheilos, Greek for ‘lip’ (Brönnimann and Resig, 1971), with the latter word neuter, thus requiring pristinum as the specific name. [Smart & Thomas 2018] 

Catalog entries: Streptochilus pristinum

Type images:

Distinguishing features: Test with straight lateral profile in early portion of the test followed inflation of the later chambers

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:

Distinguished from other species of the genus by the “straight lateral profile of the early portion of the test followed by the tendency toward inflation of the later chambers” (Brönnimann and Resig, 1971:1289). Streptochilus pristinum is distinguished from Chiloguembelina ototara by the more compressed test, smoother test surface, and presence of a toothplate. Streptochilus pristinum differs from S. martini and S. tasmanensis n. sp. by its straight lateral profile of the initial part of the test, followed by inflation of later chambers. It differs from S. rockallkiddensis by the lack of granular surface ornamentation, and differs from S. tasmanensis n. sp. by the lack of surface circular pore mounds. [Smart & Thomas 2018] 


Wall type: Microperforate, smooth.

Test morphology: Test biserial, early portion of test with straight lateral profile and no chamber inflation, followed by slight inflation of the later chambers, becoming gradually tapered, usually 5-8 pairs of chambers; sutures straight to slightly curved and depressed; aperture a narrow high arch with a rim/collar at the outer margin and the opposite margin turned in to form a ramp to the collar of the previous aperture. [Smart & Thomas 2018]

Size: Holotype length 0.18 mm, width 0.08 mm; length range 0.13-0.25 mm, maximum width 0.10 mm. [Smart & Thomas 2018]

Character matrix

test outline:Triangularchamber arrangement:Biserialedge view:Compressedaperture:Interiomarginal
sp chamber shape:Subrectangularcoiling axis:N/Aperiphery:N/Aaperture border:Thin flange
umb chbr shape:Subrectangularumbilicus:N/Aperiph margin shape:Narrowly roundedaccessory apertures:None
spiral sutures:Moderately depressedumb depth:N/Awall texture:Smoothshell porosity:Microperforate: <1µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:2.0-2.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: The distribution during the Oligocene is unknown as it is very rare; currently known from Syria, New Zealand and the Pacific Ocean. [Smart & Thomas 2018]

Isotope paleobiology: No data available. [Smart & Thomas 2018]

Phylogenetic relations: Resig (1993) suggested that the evolution of S. pristinum occurred before the mid-late Oligocene, either from C. cubensis or from an undiscovered ancestral Eocene Streptochilus. Resig (1993) commented that the appearance of S. pristinum in the late Oligocene of New Zealand (Hornibrook, 1990), as compared with the low latitude occurrence at ODP Site 807 (Ontong Java Plateau), implies that the evolution of S. pristinum may have occurred in mid-latitudes rather than the tropics. However, some Recent biserial foraminifera are able to live tychopelagically, suggesting a similar lifestyle for species in the past, and potential polyphyletic evolution of planktonic from benthic biserial groups (Darling and others, 2009). The distribution of S. pristinum might, therefore, signify multiple excursions of tychopelagic individuals from the coastal benthos to the pelagic zone (Darling and others, 2009), and its ancestor is unknown. [Smart & Thomas 2018]

Most likely ancestor: benthic ancestor - at confidence level 2 (out of 5). Data source: Smart & Thomas 2018.

Biostratigraphic distribution

Geological Range:
Notes: Upper Oligocene (Zone O6) (Syria) to upper Miocene (Subzone M13a) (Ontong Java Plateau, Resig, 1993), intermittent. [Smart & Thomas 2018] [Smart & Thomas 2018]
Last occurrence (top): within M13a subzone (8.58-9.83Ma, top in Pannonian stage). Data source: Smart & Thomas 2018
First occurrence (base): within O6 zone (25.21-26.93Ma, base in Chattian stage). Data source: Smart & Thomas 2018

Plot of occurrence data:

Primary source for this page: Smart & Thomas 2018 - Olig Atlas chap.19 p.501

References:

Beldean, C., Filipescu, S. & Bălc, R. (2010). An Early Miocene biserial foraminiferal event in the Transylvanian Basin (Romania). Geologica Carpathica. 61: 227-234. gs

Beldean, C., Bercea, R. & Filipescu, S. (2013). Sedimentology and biostratigraphy of the Early-Middle Miocene transition in NW Transylvanian Basin (Pâglişa and Dej sections). Studia Universitatis Babes-Bolyai Geologia. 58: 57-70. gs

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

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. Proc. Natl. Acad. Sci. U. S. A.. 106: 12629-12633. gs

de Klasz, I., Kroon, D. & Van Hinte, J. E. (1989). Notes on the foraminiferal genera Laterostomella de Klasz and Rérat and Streptochilus Brönnimann and Resig. Journal of Micropalaeontology. 8: 215-226. gs

Hernitz Kucenjak, M., Premec Fucek, V., Slavkovic, R. & Mesic, I. A. (2006). Planktonic foraminiferal biostratigraphy of the late Eocene and Oligocene in the Palmyride area, Syria. Geologia Croatica. 59: 19-39. gs

Hornibrook, N. d. B. (1990). Chiloguembelina cubensis (Palmer) and C. ototara (Finlay), in New Zealand. Journal of Foraminiferal Research. 20(4): 368-371. gs

Jenkins, D. G. & Srinivasan, M. S. (1986). Cenozoic planktonic foraminifera from the equator to the sub-antarctic of the Southwest Pacific. Initial Reports of the Deep Sea Drilling Project. 90: 795-834. gs

Premec Fucek, V., Hernitz Kucenjak, M. & Huber, B. T. (2018). Taxonomy, biostratigraphy, and phylogeny of Oligocene Chiloguembelina and Jenkinsina. 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: 459-481. gs

Resig, J. M. (1993). Cenozoic stratigraphy and paleoceanography of biserial planktonic foraminifers, Ontong Java Plateau. Proceedings of the Ocean Drilling Program, Scientific Results. 130: 231-244. 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


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Streptochilus pristinum compiled by the pforams@mikrotax project team viewed: 22-8-2019

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