Polycamerella

Daughter taxa (time control age-window is: 0-800Ma)
			Polycamerella tardata Differs from all species of Planohedbergella and Laeviella by having: (1) consistent presence of a biapertural final chamber bearing broad, low apertural slits that open along the outer margin of the umbilicus and are bordered by infolding tubular apertural flaps that usually project directly into the umbilicus, (2) a more weakly lobate peripheral outline, (3) the slowest, continuously log-linear chamber expansion rate (text-figs. 4a, 4e, 6), and (4) the greatest total number of chambers in the adult test (average = 23).

Taxonomy

Original description:

Type of wall: Finely perforate with pores averaging 1.9 mm and ranging from 1.1–2.4 mm, wall surface with randomly scattered, fine muricae.

 Test morphology: Test planispirally coiled, biumbilicate, moderately evolute with a relatively broad, shallow umbilicus (U_D:T_D ratio average 0.31), equatorial outline weakly lobate, subcircular in peripheral outline with a rounded to subrounded peripheral margin, symmetrical in edge view, always biapertural; chambers weakly inflated, enlarging very slowly in size (y = 0.092x + 1.77) with uniform, log-linear growth throughout ontogeny (text-figs. 4a, 4e, 6), 22–23 total chambers in adult specimens usually coiled in 2.5 whorls (e.g., Pl. 21, Figs. 1c, 2c, 5c), average of 7.7 chambers and range of 7.0–8.5 chambers in the final whorl (Table 1), kummerform chambers rare (U_CL:P_CL ratio average 1.0); sutures slightly curved, weakly depressed; final chamber biapertural with a low arch or slit opening into the umbilicus, may show inward flexure along suture (Pl. 21, Figs. 1a, 3a, 5a, 6a, 8, 9a), bordered by a narrow, imperforate flap that extends into the umbilicus connecting with previous chambers, and may become outwardly folded and tubular shaped (e.g., Pl. 21, Figs. 1a, 3a, 5a, 6a, 11); relict apertures and apertural flaps visible surrounding the umbilicus.

Entries in the Catalog of original descriptions: Polycamerella

Distinguishing features:
Parent taxon (Globigerinelloididae): Test planispiral, chambers globular to radially elongate; aperture at the base of the chamber face and equatorial in position, lateral portions of primary aperture may remain open as new chambers are added, forming relict openings around the umbilical region.
This taxon: Differs from all species of Planohedbergella and Laeviella by having: (1) consistent presence of a biapertural final chamber bearing broad, low apertural slits that open along the outer margin of the umbilicus and are bordered by infolding tubular apertural flaps that usually project directly into the umbilicus, (2) a more weakly lobate peripheral outline, (3) the slowest, continuously log-linear chamber expansion rate (text-figs. 4a, 4e, 6), and (4) the greatest total number of chambers in the adult test (average = 23).

Diagnostic characters:

Most likely ancestor:
Planohedbergella - at confidence level 0 (out of 5). Data source: Huber et al 2022 fig. 2.

Geological Range:
Last occurrence (top): at top of Late Maastrichtian Substage (100% up, 66Ma, in Danian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within Late Campanian Substage (72.17-76.20Ma, base in Campanian stage). Data source: Total of ranges of species in this database

Plot of range and 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
• See also: customisable plot Parent: Globigerinelloididae

Polycamerella compiled by the pforams@mikrotax project team viewed: 9-12-2025 Taxon Search: Advanced Search Short stable page link: https://mikrotax.org/pforams/index.php?id=110599 Go to Archive.is to create a permanent copy of this page - citation notes

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