pforams@mikrotax - Hedbergella tatianae pforams@mikrotax - Hedbergella tatianae

Hedbergella tatianae


Classification: pf_mesozoic -> Hedbergellidae -> Hedbergella -> Hedbergella tatianae
Sister taxa: << < H. maslakovae, H. mitra, H. modesta, H. occulta, H. praelippa, H. praetrocoidea, H. primare, H. quadricamerata, H. roblesae, H. ruka, H. semielongata, H. sigali, H. similis, H. speetonensis, H. tardita, H. tatianae, H. trocoidea, H. tunisiensis, H. tuschepsensis, H. ventriosa, H. sp.

Taxonomy

Citation: Hedbergella tatianae (Banner & Desai, 1988)
taxonomic rank: Species
Basionym: Praehedbergella tatianae

Type images:

Original description: The test consists of about two whorls of chambers. 4½ chambers in the first whorl and 4 in the final whorl. The spiral side is almost flat; the umbilical side is more convex and has a narrow, deep umbilicus which is in breadth equal to about 1/8th of the test diameter. The chambers become reniform and depressed with growth, to become about half as high as long when seen on the spiral side. The aperture is a narrow slit, umbilical to extraumbilical, nearly but not quite reaching the periphery of the previous whorl, and is furnished with a porticus which is broadest at its umbilical end. The surface of the test is smooth and nonmuricate: it is uniformly microperforate, the microperforations being about 0.6 mu m in diameter but often broadened at their outer ends (through test erosion) to about 1.5 µm. "Test erosion (fig. 1b) also shows how the perforations are the external openings of canaliculi, which have erosion-resistant granular walls (analogous to those of benthic rotalines as described by Banner and Williams, 1978. Early stages of test surface dissolution (fig. 2b) also reveal the sutural margins between adjacent canalicular walls (compare Banner and Williams, 1978, pl. 2).

Entries in the Catalog of original descriptions: Praehedbergella tatianae

Character matrix
test outline:chamber arrangement:Trochospiraledge view:aperture:
sp chamber shape:Globularcoiling axis:Very lowperiphery:aperture border:Thin porticus
umb chbr shape:umbilicus:periph margin shape:accessory apertures:
spiral sutures:Moderately depressedumb depth:Deepwall texture:Smoothshell porosity:Microperforate: <1µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:4-4 N.B. These characters are used for advanced search. N/A - not applicable

Geological Range:
Last occurrence (top): within L. cabri zone (119.05-120.55Ma, top in Aptian stage). Data source:
First occurrence (base): within L. cabri zone (119.05-120.55Ma, base in Aptian stage). Data source:

Plot of range and occurrence data:

References:

Banner, F. T. & Desai, D. (1988). A review and revision of the Jurassic-Early Cretaceous Globigerinina,with especial reference to the Aptian assemblages of Speeton (North Yorkshire, England). Journal of Micropalaeontology. 7: 143-185. gs


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Hedbergella tatianae compiled by the pforams@mikrotax project team viewed: 14-6-2024

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