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Hedbergella praetrocoidea


Classification: pf_mesozoic -> Hedbergellidae -> Hedbergella -> Hedbergella praetrocoidea
Sister taxa: << < H. excelsa, H. gorbachikae, H. handousi, H. hexacamerata, H. hispaniae, H. infracretacea, H. kuhryi, H. kuznetsovae, H. labocaensis, H. luterbacheri, 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. sp.,

Taxonomy

Citation: Hedbergella praetrocoidea Kretchmar and Gorbachik, in Gorbachik, 1986
Rank: Species
Basionym: Hedbergella praetrocoidea
Taxonomic discussion: Hedbergella praetrocoidea differs from its descendent Hd. trocoidea (Gandolfi, 1942) in having fewer chambers in the outer whorl (5.5–6.5 instead of 6.5–7.5) and a wider and shallower umbilical area, and in having less embracing chambers (Huber and Leckie, 2011)

Type images:

Original description: Test small, high spired. Both right- and left-coiling specimens occur. Height of coil variable. Spiral side usually convex, more rarely flat. Umbilical side concave. Contour of test lightly oval, lobate. Peripheral margin broad, rounded. Adult tests consist of 2.5-3 whorls. Total number of chambers 14-19, specimens with 17 chambers predominate. First whorl has 5-5.5 chambers, later whorls 6-7. Number of chambers per whorl increases each whorl by a half to one chamber. First 4-6 chambers spherical. Later chambers are trapezoidal on the spiral side, last 2-4 chambers are kidney-bean-shaped.

Entries in the Catalog of original descriptions: Hedbergella praetrocoidea


Emended description: Test medium sized, coiled in a low trochospire; 2 to 2.5 whorls; 6 to 6.5 chambers in the outer whorl increasing gradually and slowly in size as added; chambers subtriangular to triangular on the umbilical side, subspherical to trapezoidal in the spiral side, reniform in lateral view; equatorial periphery subcircular to slightly ovoid, slightly lobate; sutures depressed, radial to slightly curved; umbilical area rather wide and shallow; aperture as a low to medium arch bordered by a lip. Wall smooth, finely perforate, that may be covered by perforation cones in the early chambers of the last whorl. [copied from Chronos database]

Geological Range:
Last occurrence (top): within T. bejaouaensis zone (113.26-118.02Ma, top in Aptian stage). Data source: [copied from Chronos database]
First occurrence (base): within G. blowi zone (125.71-128.73Ma, base in Barremian stage). Data source: [copied from Chronos database]

Plot of occurrence data:

Dec 2017 - Plotting of Neptune data has been re-enabled on the Mesozoic pages following revision of the age-models in Neptune. The data is, however, still very sparse for the Early Cretaceous

  • (NB There is no histogram as there are no occurrence records for the taxon in the Neptune database) Parent: Hedbergella

    Character matrix

    test outline:Lobatechamber arrangement:Trochospiraledge view:Spiroconvexaperture:-
    sp chamber shape:Globularcoiling axis:Lowperiphery:N/Aaperture border:Thin lip
    umb chbr shape:Globularumbilicus:Narrowperiph margin shape:Broadly roundedaccessory apertures:N/A
    spiral sutures:Moderately depressedumb depth:Shallowwall texture:Smoothshell porosity:Finely Perforate: 1-2.5µm
    umbilical or test sutures:Moderately depressedfinal-whorl chambers:6.0-6.5 N.B. These characters are used for advanced search. N/A - not applicable

    References:

    Gorbachik, T. N. (1986). Jurassic and early Cretaceous planktonic foraminifera of the south of the USSR. Moscow: Izdat. “Nauka”. 1986: 120-. gs

    Leckie, M. (1984). Mid-Cretaceous planktonic foraminiferal biostratigraphy off Central Morocco, Deep Sea Drilling Project Leg 79, Sites 545 and 547. Initial Reports of the Deep Sea Drilling Project. 79: 579-620. gs


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    Hedbergella praetrocoidea compiled by the pforams@mikrotax project team viewed: 6-4-2020

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    Short stable page link: http://mikrotax.org/pforams/index.php?id=110257 Go to Archive.is to create a permanent copy of this page - citation notes



    Comments (1)

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    Carol Johnsson (Brazil)

    the photo DSDP Site 511-144.DSDP here, is equal of Huber and Leckie 2011_5-10-134JPG of Hedbergella infracretacea.

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    Brian Huber (Washington)

    Thank you for pointing out this mistake!

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    Jeremy Young (Tonbridge, UK)

    We have now deleted the copy of the image which was here accidentally. It is almost inevitable that mistakes get onto the site so it is really useful when they are pointed out.

    Jeremy

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