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Hedbergellidae


Classification: pf_mesozoic -> Hedbergellidae
Sister taxa: Guembelitriidae, Heterohelicidae, Planomalinidae, Globigerinelloididae, Schackoinidae, Conoglobigerinidae, Chilostomellidae, Favusellidae, Praehedbergellidae, Hedbergellidae, Rugoglobigerinidae, Rotaliporidae, Globotruncanidae, hidden,
Daughter taxa (blue => in age window 0-300Ma) Granddaughter taxa
Test in a low trochospiral coil, early chambers globular, increasing rapidly in size, those of the final whorl pyriform to subconical and may terminate in a tubulospine, resulting in a stellate peripheral outline, umbilical side deeply excavated centrally, sutures radial, depressed, periphery angular but lacking an imperforate carinal band; wall calcareous, radiate, finely perforate, surface smooth to finely hispid but without costellae; aperture a low interiomarginal arch, extraumbilical-umbilical, bordered by a narrow lip.

Test flattened, early globular chambers in a low trochospiral coil, last few chambers radially elongate to subclavate in the plane of coiling, peripheral outline lobulate, rounded peripheral margin with an imperforate band on the globular chambers but absent from the elongate ones; aperture a moderately high interiomarginal umbilical-extraumbilical arch, with imperforate bordering lip, and poorly developed relict apertures remaining in the umbilical area.

Test with low to medium trochospiral coil of few, rapidly enlarging, spherical chambers per whorl, sutures radial, depressed, periphery rounded, peripheral margin lobulate; wall calcareous, hyaline, optically radial, finely perforate, surface with meridionally aligned pustules and costellae resulting from fusion of adjacent pustules; aperture a low interiomarginal, umbilical to slightly extraumbilical arch, with a narrow bordering lip.

Test in low trochospiral coil, compressed, chambers petaloid, sutures radial, slightly curved, depressed on the spiral side, radial and depressed around the shallow umbilicus on the umbilical side, peripheral margin truncate to narrowly rounded, with imperforate carinal band bordered in the earlier chambers of the final whorl by two low pustulose keels, peripheral outline lobulate; wall calcareous, perforate, rare perforations may occur in the generally imperforate carinal band, surface of earlier chambers pustulose, especially on the spiral side; primary aperture interiomarginal, umbilical-extraumbilical, nearly equatorial, bordered with a thin lip but lacking portici or umbilical extensions.

Test trochospiral, wall finely perforate, outer wall weakly to densely covered with perforation cones or perforation ridges (coalescing perforation cones); umbilical and spiral sutures depressed, radial, straight to slightly curved; aperture an interiomarginal extraumbilical-umbilical arch with a thin imperforate rim, rarely with a narrow bordering lip.

Test in low trochospiral coil, planoconvex, spiral side flattened, umbilical side inflated, with narrow to moderately wide central umbilicus of about one-third to one-fourth the test diameter, chambers subtriangular, broad and inflated on the umbilical side, sutures radial and slightly depressed or may be elevated on the spiral side, peripheral margin marked by a row of pustules or a single keel, peripheral outline lobulate; primary aperture umbilical-extraumbilical, bordered by a well-developed flap or porticus, those of successive chambers overlapping in a ring about the umbilicus but do not fuse.

Smooth, very low trochospiral test, finely perforate to macroperforate test wall, crater-like pores on the earlier chambers and imperforate peripheral band throughout the final whorl.

Test wall thin, microperforate, surface smooth or with scattered and weakly developed pustules. Test low trochopiral, small, chambers globular, increasing rapidly to moderately in size, with 3–6 in the final whorl; aperture a low interiomarginal, umbilical-extraumbilical arch bordered by a thin lip or flap.



Test wall multilamellar, finely perforate, wall pores, surface moderately to coarsely muricate or pustulose; test coiled in a very low to low trochospire; chambers globular with 4.5-7 in the final whorl; aperture a low interiomarginal, umbilical-extraumbilical arch bordered by a thick lip or flap.

Test low to moderate trochospiral, globular chambers with a broadly rounded periphery, lacking peripheral structures; primary aperture extraumbilical-umbilical, bordered by a narrow, imperforate lip; test ornamentation asymmetrical with respect to the peripheral plane, rugosities and sharp costellae arranged following a meridional pattern on the umbilical side, and parallel to the periphery on the spiral side.

Test low trochospiral, numerous chambers (7–11) in the last whorl, sutures straight and depressed on both sides; wall finely perforate, rugose to smooth,rugosities organized in irregularly sized ridges that may cover the pores and run parallel to the spiral suture, may have bear volcano-like perforation cones; umbilical area may be covered by large flaps primary aperture umbilical-extraumbilical; may have one to two small umbilical accessory apertures in last chambers.



Test trochospiral, biconvex to spiroconvex, umbilicate, periphery subangular with prominent nonporous carinal band that may have numerous pustules in the earlier part of the last whorl but is less distinct on the final chamber, sutures curved on the spiral side, radial on the umbilical side, flush to slightly depressed; wall calcareous, finely and densely perforate, radial in structure, surface smooth to pustulose or nodose, most rugose on the early chambers and keel; aperture an interiomarginal, extraumbilical-umbilical arch that extends to the periphery, bordered by an imperforate lip or flap.

Test wall microperforate with pores surrounded by small-sized perforation cones; pustules may be present in the umbilical region. Test small, with early hedbergellid stage and higher trochospire in the adult. Chambers coiled in a variable trochospire with 4.5–5.0 chambers in the initial whorl and 3–4 chambers in the final whorl. Aperture a low interiomarginal, umbilical-extraumbilical arch without periapertural structures.

Test in low trochospiral coil, chambers globular, five to seven in the final whorl, increasing gradually in size, sutures radial, depressed; wall calcareous, finely perforate, surface pustulose, especially on earlier chambers; aperture an interiomarginal, umbilical-extraumbilical arch, bordered by a wide apertural flap or porticus that extends into the umbilicus, those of successive chambers overlapping but not attached to previous flaps.

Taxonomy

Citation: Hedbergellidae Loeblich & Tappan 1961
Rank: Family

Type images:

Original description: Hedbergellidae Loeblich and Tappan, 1961: Primary aperture only, commonly with prominent aperture lip, those of previous chambers remaining as projections into the umbilical region.

Entries in the Catalog of original descriptions: Hedbergellidae;

Short diagnosis: Test trochospirally coiled, primary aperture interiomarginal, extraumbilical-umbilical, with prominent apertural lip, apertures of earlier chambers remain visible around the umbilical region; no sutural secondary apertures.

Geological Range:
Last occurrence (top): within Maastrichtian Stage (66.04-72.05Ma, top in Maastrichtian stage). Data source: Total of range of species in this database
First occurrence (base): within Valanginian Stage (133.88-139.39Ma, base in Valanginian stage). Data source: Total of range of species in this database

Plot of occurrence data:

NB Plotting of Neptune data has been disabled on the Mesozoic pages because the dataset is both small and badly affected by a few sites with erroneous age models (our obs Huber, Petrizzo, Young, Nov 2016). The data can still be viewed via the range plottertool - tools menu.

References:

Loeblich, A.R., Jr. & Tappan, H., (1961). Cretaceous planktonic foraminifera: Part I-Cenomanian. Micropaleontology, 7: 257-304.

Loeblich, A.R., Jr. & Tappan, H. (Editors), (1988). Foraminiferal Genera and Their Classification (Volume I-II). Van Nostrand Reinhold Co., New York, 1059 pp.


Hedbergellidae compiled by the pforams@mikrotax project team viewed: 30-3-2017

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