pforams@mikrotax - Chiloguembelina parallela

pforams@mikrotax - Chiloguembelina parallela pforams@mikrotax - Chiloguembelina parallela

Chiloguembelina parallela

Classification: pf_cenozoic -> Guembelitrioidea -> Chiloguembelinidae -> Chiloguembelina -> Chiloguembelina parallela
Sister taxa: C. adriatica, C. cubensis, C. andreae, C. ototara ⟩⟨ C. parallela, C. trinitatensis, C. wilcoxensis, C. crinita ⟩⟨ C. subtriangularis, C. midwayensis, C. morsei, C. sp.

Taxonomy

Citation: Chiloguembelina parallela Beckmann 1957

taxonomic rank: Species

Basionym: Chiloguembelina parallela

Synonyms:

Chiloguembelina parallela Beckmann, 1957:91, pl. 21: fig. 8, text-fig. 15 (36-38) [lower Eocene, upper Lizard Springs Fm., Cascas River bank, southern Trinidad].

Taxonomic discussion: The holotype of C. parallela (Pl.16.3, Figs. 11-12) shows the rapidly tapering test and centered, highly arched aperture that are characteristic of this species. Despite these distinctive features this species has not been reported outside of Trinidad, perhaps because it has been overlooked. [Huber et al. 2006]

Catalog entries: Chiloguembelina parallela

Type images:

holotype: C. parallela
holotype: C. parallela

Distinguishing features:
Parent taxon (Chiloguembelina): Test subtriangular in outline, biserial throughout or rarely with multiserial final chambers; aperture a simple arched opening at base of the final chamber, with a narrow rim on one margin and a broad collar or flange directed toward one of the flat sides of the test, lacking an infolded margin or internal plate. Rarely with multiple apertures.
This taxon: Test short and thick, tapering rapidly toward its base. Aperture centrally located, symmetrical, high and narrow.

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 short, rapidly tapering, periphery rounded rather than compressed; chambers biserial, increasing moderately in size, globular, sutures moderately depressed, slightly oblique toward apical axis; aperture a high, narrow, and symmetrical arch bordered by two parallel lateral flanges, occasionally covered by irregularly shaped terminal chamber. [Huber et al. 2006]

Wall type:

Microperforate, finely pustulose, lacking pore mounds or striae. [Huber et al. 2006]

Size:

Holotype (USNM 5780) length 0.12 mm, width 0.11 mm, breadth 0.07 mm. [Huber et al. 2006]

Character matrix
test outline: Subtriangular chamber arrangement: Biserial edge view: Equally biconvex aperture: Interiomarginal
sp chamber shape: Globular coiling axis: N/A periphery: N/A aperture border: Thick flange
umb chbr shape: Globular umbilicus: N/A periph margin shape: Broadly rounded accessory apertures: None
spiral sutures: Moderately depressed umb depth: N/A wall texture: Finely pustulose shell porosity: Microperforate: <1µm
umbilical or test sutures: Moderately depressed final-whorl chambers: 2-2 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology

Geographic distribution

This species has not been reported outside of Trinidad. [Huber et al. 2006]

Isotope paleobiology

No data are available. [Huber et al. 2006]

Phylogenetic relations

According to Beckmann (1957), C. parallela probably descended from Chiloguembelina crinita during the early Eocene. [Huber et al. 2006]

Most likely ancestor: Chiloguembelina trinitatensis - at confidence level 4 (out of 5). Data source: Huber et al. 2006, f16.2.

Biostratigraphic distribution

Geological Range:
Notes: Lower Eocene Zone E3 to middle Zone E4. Beckmann (1957) suggested that C. parallela is a good index marker for the lower Eocene as it has a short range within the Globorotalia rex Zone in the upper Lizard Springs Fm. of Trinidad. [Huber et al. 2006]
Last occurrence (top): in mid part of E4 zone (50% up, 53.6Ma, in Ypresian stage). Data source: Huber et al. 2006, f16.2
First occurrence (base): within E3 zone (54.61-55.20Ma, base in Ypresian stage). Data source: Huber et al. 2006, f16.2

Plot of occurrence data:

Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
(NB There is no histogram as there are no occurrence records for the taxon in the Neptune database) Parent: Chiloguembelina

Primary source for this page: Huber et al. 2006 - Eocene Atlas, chap. 16, p. 475

References:

Beckmann, J. P. (1957). Chiloguembelina Loeblich and Tappan and related foraminifera from the Lower Tertiay of Trinidad, B.W.I. In, Loeblich, A. R. , Jr., Tappan, H., Beckmann, J. P., Bolli, H. M., Montanaro Gallitelli & E. Troelsen, J. C. (eds) Studies in Foraminifera. U.S. National Museum Bulletin . 215: 83-95. 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 O

Chiloguembelina parallela compiled by the pforams@mikrotax project team viewed: 9-10-2024

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test outline:	Subtriangular	chamber arrangement:	Biserial	edge view:	Equally biconvex	aperture:	Interiomarginal
sp chamber shape:	Globular	coiling axis:	N/A	periphery:	N/A	aperture border:	Thick flange
umb chbr shape:	Globular	umbilicus:	N/A	periph margin shape:	Broadly rounded	accessory apertures:	None
spiral sutures:	Moderately depressed	umb depth:	N/A	wall texture:	Finely pustulose	shell porosity:	Microperforate: <1µm
umbilical or test sutures:	Moderately depressed	final-whorl chambers:	2-2	N.B. These characters are used for advanced search. N/A - not applicable