Nannotax3 - ntax_cenozoic - B. inflatus group Nannotax3 - ntax_cenozoic - B. inflatus group

B. inflatus group


Classification: ntax_cenozoic -> Syracosphaerales -> Rhabdosphaeraceae -> Blackites -> B. inflatus group
Sister taxa: B. morionum group, B. clavus group, B. inflatus group, B. spinosus group, B. amplus group, B. sp.

Daughter taxa (time control age-window is: 0-800Ma)
Blackites aktulagayensis

Blackites bullatus
Rhabdolith with a hollow bulb-shaped spine (maximum width similar to that of the coccolith); the rim is relatively broad and the outer cycle does not lie distally over the inner cycle.
Blackites creber
Rhabdoliths with tall, narrow, hollow styliform spines, near parallel for much of their length, but that may broaden slightly in the upper half. The upper quarter of the spines display a distinctive striated pattern. The coccolith is relatively broad, and the spine usually less than half its width and may show a basal collar.
Blackites culter
Rhabdolith with a tall spine that has concave depressions running along its length, producing either a three (Y-shaped), or possibly four-fold (X-shaped), symmetry across the axis of the spine.
Blackites flammeus
Rhabdolith coccolith with a relatively narrow coccolith base and a flame-shaped, slightly asymmetric, hollow spine.
Blackites fustis
Rhabdolith with a relatively wide, hollow ampulliform spine that is initially near parallel-sided, expands distally and then terminates sharply in a domed top, often with a small papilla. The spine reaches a width similar to that of the coccolith. The rim is relatively broad and the outer cycle does not lie distally over the inner cycle.
Blackites gladius
Rhabdoliths with hollow ampulliform spines with a prominent basal collar and narrow base, widening to a maximum around three quarters of the way up, then taper to a point; the upper half of the spines display a distinctive striated pattern. The basal coccoliths are broad, the spine width is usually around half the coccolith width.
Blackites globosus
Rhabdolith with hollow spine that rapidly expands into a sphere (maximum width almost twice that of the coccolith base). The spine has a short narrow collar, a pinched distal termination, and shows a distinctive cross-hatched pattern in its upper part. The rim is relatively broad and the outer cycle does not lie distally over the inner cycle.
Blackites herculesii
Rhabdolith with a broad, club-like (claviform) spine with width typically only slightly less than that of the coccolith. The spine displays a distinctive cross-hatched pattern and the outer surface may be serrated. The outer cycle of the coccolith rim is significantly smaller the inner.
Blackites inflatus
Rhabdolith with a tall, hollow, ampulliform spine that broadens to a maximum width and then tapers gradually in the upper portion; the outer surface is serrated. The width of the spine is variable and typically the same as the coccolith but considerable taller (x4-7). The rim is distinctly convex and relatively broad.
Blackites kilwaensis
Rhabdoliths with a tall, narrow trumpet-like (salpingiform) spine that terminates in a sharply tapering spine top; the coccolith is small and only one cycle is visible in the LM.
Blackites ornatus
Large, table tennis bat-shaped spine covered in fine, cross-hatch ornamentation when viewed in XPL. The spines have not been found attached to a coccolith base, and they appear to be rather flat.
Blackites piriformis
Rhabdoliths with a wide, hollow, ampulliform spine that broadens rapidly to a maximum width and then tapers to a narrow upper portion; the inflated part of the spine displays a distinctive cross-hatched pattern and the outer surface is serrated. The spine is much taller (x 3) and wider than the coccolith.
Blackites praeinflatus

Blackites pseudomorionum
Rhabdoliths with a relatively tall, broad, hollow spine that widens to a maximum and then tapers sharply to a point, forming a distinctive angular inflection point. The inflection point appears to be at the junction of two structural units that are distinct in XPL. Typically the spine is much taller (x 2), but approximately the same width, as the coccolith.
Blackites rotundus
Rhabdoliths with hollow ampulliform spines that are narrow at their base and wide and rounded distally; the inflated part of the spine displays a distinctive striated pattern. The coccolith is broad, and the outer cycle lies distally over the inner cycle and forms the outer edge of the coccolith. The spine is greater than half the width of the coccolith and usually has a prominent basal collar.
Blackites rugosus

Blackites sextonii

Blackites turritus
Rhabdolith with a tall spine constructed from at least two or three distinct structural/crystallographic units when viewed in XPL; there may be a small, terminal papilla. Typically the spine is taller than the width of the coccolith and near parallel-sided or slightly tapering before terminating quite sharply; it is usually about half the width of the coccolith. The rim is relatively broad and the outer cycle does not lie distally over the inner cycle.
Blackites virgatus
Large rhabdoliths with a tall hollow spine that is widest at its base, tapers to a point and is distinctively coarsely striated in XPL. The rim is broad and the outer cycle does not lie distally over the inner cycle. Screw-like in overall appearance.

Taxonomy:

Citation: Blackites inflatus group
Taxonomic rank: species group
Taxonomic discussion: informal grouping used here to sort species within this large genus

Distinguishing features:
Parent taxon (Blackites): Coccoliths process-bearing with complex base including outer rim, radial lath and lamellar cycles
This taxon: Spine inflated with maximum width above base, many with conspicous bulge

Farinacci & Howe catalog pages:


Size:
Basal diameter of coccoliths typically 3-5 µm, spine height much more variable - 5-20 µm and varying significantly between species. [my obs from review of specimens on the Nannotax - JRY 2017]

Search data:
Lith size: 4->20µm;
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): at top of NP21 zone (100% up, 32.9Ma, in Rupelian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within NP9 zone (55.86-57.21Ma, base in Thanetian stage). Data source: Total of ranges of species in this database

Plot of occurrence data:

References:


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B. inflatus group compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 19-2-2025

Taxon Search:
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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=59 Go to Archive.is to create a permanent copy of this page - citation notes
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