pforams@mikrotax - Laeviella pforams@mikrotax - Laeviella

Laeviella


Classification: pf_mesozoic -> Globigerinelloididae -> Laeviella
Sister taxa: Eohastigerinella, Globigerinelloides, Hastigerinoides, Laeviella, Planohedbergella, Polycamerella, Pseudoschackoina
Daughter taxa (time control age-window is: 0-800Ma)
Laeviella bentonensis

Laeviella bollii

Laeviella primuloides

Laeviella tururensis

Taxonomy

Citation: Laeviella Huber et al 2022
taxonomic rank: Genus
Type species: Anomalina bentonensis Morrow 1934
Taxonomic discussion:

The primary criterion for inclusion of La. primuloides, La. bentonensis, La. tururensis, and La. bollii in Laeviella is the presence of a smooth shell surface texture on all but the earliest final whorl chambers and a finely perforate wall ultrastructure.

The oldest species of Laeviella, La. primuloides, is considered a direct descendent of Ticinella primula Luterbacher (text-fig. 2). Evidence for this transition is based on study of the Col de Palluel section (Vocontian Basin, SE France, Gale et al. 2011), which revealed that La. bentonensis (e.g., Pl. 2, Figs. 12, 13) occurs within the range of Ticinella primula (e.g., Pl. 5, Fig. 8), and its first occurrence is just above a morphotype that is intermediate between Ti. primula and La. bentonensis and is denoted as La. primuloides (Pl. 5, Fig. 9). Similar to Ti. primula, La. primuloides has a deeply pitted, irregularly rugose (ticinellid) wall surface texture on the first chambers of the final whorl, but its planispiral coiling mode and smooth wall texture on the last chambers of the final whorl (e.g., Pl. 2, Figs. 1c, 2b, 3c, 4c, 5b, 6b, 7b), justify its inclusion in Laeviella.

Entries in the Catalog of original descriptions: Laeviella

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: Planispiral, wall texture smooth except sometimes pustulose early chambers, weakly lobate with 6-9 chambers in final whorl.


Morphology:
Planispiral, biumbilicate with a shallow, narrow umbilicus, peripheral outline weakly lobate; early chambers rounded and globular, later chambers becoming elongated in growth direction; coiling moderately evolute with 6–9 gradually expanding chambers in the final whorl; sutures radial to slightly curved, weakly depressed; aperture usually a single, symmetrically position, low equatorial arch bordered by a narrow lip, biapertural forms very rare with apertures opening near umbilicus on final chamber.

Wall type:
Finely perforate to macroperforate with average pore diameters of included species ranging from 1.9 microns to 2.6 microns surface smooth on chamber sides, weak pustules sometimes present on early final whorl chambers. 

Size:
Dimensions of holotype of genotype: 400 microns maximum diameter, 200 microns breadth.

Character matrix
test outline:Subcircularchamber arrangement:Planispiraledge view:-aperture:Interiomarginal
sp chamber shape:-coiling axis:-periphery:-aperture border:Thin lip
umb chbr shape:-umbilicus:-periph margin shape:-accessory apertures:None
spiral sutures:-umb depth:-wall texture:Smoothshell porosity:-
umbilical or test sutures:Weakly depressedfinal-whorl chambers:6-9 N.B. These characters are used for advanced search. N/A - not applicable

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

Geological Range:
Last occurrence (top): at top of G. aegyptiaca zone (100% up, 73.8Ma, in Campanian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within T. primula zone (107.39-111.84Ma, base in Albian stage). Data source: Total of ranges of species in this database

Plot of range and occurrence data:

References:

Huber, B. T., Petrizzo, M. M. & Falzoni, F. (2022b). Taxonomy and phylogeny of Albian–Maastrichtian planispiral planktonic foraminifera traditionally assigned to Globigerinelloides. Micropaleontology. 68(2): 117-183. gs


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Laeviella compiled by the pforams@mikrotax project team viewed: 21-7-2024

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Short stable page link: https://mikrotax.org/pforams/index.php?id=110597 Go to Archive.is to create a permanent copy of this page - citation notes



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