pforams@mikrotax - Streptochilus subglobigerum pforams@mikrotax - Streptochilus subglobigerum

Streptochilus subglobigerum


Classification: pf_cenozoic -> Benthic origins -> Streptochilus -> Streptochilus subglobigerum
Sister taxa: 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 subglobigerum Resig 1989
taxonomic rank: species
Basionym: Streptochilus subglobigerum Resig 1989

Catalog entries: Streptochilus subglobigerum

Type images:

Distinguishing features:
Parent taxon (Streptochilus): Like Chiloguembelina but with an internal plate connecting successive chambers, a prominent extension of an apertural collar, and a smoother surface texture.
This taxon: Wall finely perforate and finely cancellate, becoming smooth in 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


Morphology:
Test biserial with 6 pairs of inflated chambers separated by incised, relatively straight sutures; test sometimes twisted, tapering rapidly toward the proloculus. Wall finely perforate and finely cancellate, becoming smooth in the later chambers.

Aperture a wide, high arch from the base onto the face of the last chamber, bordered by a collar that is intumed on one side to fuse with an internal plate connecting with the intumed collar of the previous aperture. [Resig 1989]

Character matrix
test outline:Subtriangularchamber arrangement:Biserialedge view:Compressedaperture:Interiomarginal
sp chamber shape:Globularcoiling axis:N/Aperiphery:N/Aaperture border:Thin flange
umb chbr shape:Globularumbilicus:N/Aperiph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:Moderately depressedumb depth:N/Awall texture:Smoothshell porosity:Microperforate: <1µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:2-2 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution


Phylogenetic relations
S. subglobigerum differs from S. globigerum (cf. pl. 2, figs. 8-11) mainly in the smoothness of its final chambers, and in its discrete stratigraphic range. It tends to be more finely cancellate and more rapidly expanding than S. globigerum. Later forms of S. subglobigerum with lower, more numerous chambers or with reduced cancellations(pi. I,figs. 11, 12) are transitional to Streptochilus latum. [Resig 1989]

Biostratigraphic distribution

Geological Range:
Last occurrence (top): within N16 zone (8.58-9.83Ma, top in Tortonian stage). Data source: Resig 1989
First occurrence (base): within N15 zone (9.83-10.46Ma, base in Tortonian stage). Data source: Resig 1989

Plot of occurrence data:

Primary source for this page: Resig 1989

References:

Resig, J. M. (1989). Stratigraphic distribution of late Neogene species of the planktonic foraminifer Streptochilus in the Indo-Pacific. Micropaleontology. 35(49-62): -. gs

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Streptochilus subglobigerum compiled by the pforams@mikrotax project team viewed: 14-12-2024

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