CATALOG OF ORIGINAL DESCRIPTIONS: Globigerinatheka euganea Proto Decima & Bolli 1970

This page provides data from the catalog of type descriptions. The catalog is sorted alphabetically. Use the current identification link to go back to the main database.


Higher levels: pf_cat -> G -> Globigerinatheka -> Globigerinatheka euganea
Other pages this level: G. barri, G. curryi, G. euganea, G. kutchensis, G. lindiensis, G. subconglobata luterbacheri,

Globigerinatheka euganea

Citation: Globigerinatheka euganea Proto Decima & Bolli 1970
Rank: Species
Type locality: Cava Zillo, Este, northern Italy
Type age: Middle Eocene
Type sample and level: sample FPD 69/17, Orbulinoides beckmanni Zone, Euganei marls
Holotype Repository: Basel, Museum of Natural History,
Type & figured specimens: Plate 1, Fig. 6-11, Plate 3, Fig. 3-5, Textfig. 8-15, 31-31a, 43-45b. Holotype C 26543; paratypes C 26529- 26531, 26544.
Description on pages: 894-895

Linked specimens: USNM-244922

Current identification/main database link: Globigerinatheka euganea Proto Decima and Bolli 1970


Original Description
Test free, subspherical to nearly spherical, early coils low trochospiral with inflated chambers increasing moderately in size as added, four to six in whorl prior to the last whorl, which normally consists of two to three distinctly larger chambers, extending over the umbilical area of the erarly stage, or a single very large hemispherical chamber. The size of the ultimate chamber may vary from considerably small , rudimentary, bulla-like (tf. 8b) to approximately the same size as the penultimate (tf. 45-45b) to very large hemispherical (tf.11,11a). Small bullae may cover sutural apertures of final chamber (tfs. 12a, 13, 13a, 14a). Sutures in early stage distinct between large ultimate chambers little depressed and often barely visible. Wall calcareous, coarsely perforate. Aperture in early stage an interiomarginal, umbilical arch. In final hemispherical chamber covering the umbilical area, two to four, seldom more, small arched or semicircular to almost circular sutural openings (tf. 11, 11a). When umbilical area is covered is covered by two to three large chambers, two to four spiral and umbilical sutural apertures are present in the ultimate; in addition, one to seldom two spiral sutural apertures may exist in each of the preceding one to three large chambers (tf. 45, 45a, pl. 1, fig. 7) Rudimentary end-chambers and bullae usually have two to four small openings. Strong preference for dextral coiling.

Size: Greatest diameter of holotype 0.53 mm.

Extra details from original publication
Remarks : The new species is the intermediate form between its ancestor Globigerinatheka curryi and its successor Orbulinoides beckmanni. From the former it differs in the distinctly more spherical test shape and less incised sutures, the usually slightly more numerous but smaller sutural apertures of the final chamber, and the occasional presence of spiral sutural apertures in the preceding one to three large chambers. In overall test shape G. euganea is similar to O. beckmanni from which it differs in the lack of areal apertures and spiral sutural apertures between the early chambers. In its range G. euganea overlaps both the older G. curryi and the younger O. beckmanni. Every transitional morphological stage exists between G. euganea and its ancestor G. curryi.

Stratigraphic Range: Upper part Globorotalia lehneri Zone to lower part Orbulinoides beckmanni Zone, Middle Eocene.

References:

Premoli Silva, I., Wade, B. S. & Pearson, P. N. (2006). Taxonomy, biostratigraphy, and phylogeny of Globigerinatheka and Orbulinoides. In, Pearson, P. N. , Olsson, R. K. , Hemleben, C. , Huber, B. T. & Berggren, W. A. (eds) Atlas of Eocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication. 41(Chap 7): 169-212. gs V O

Proto Decima, F. & Bolli, H. M. (1970). Evolution and variability of Orbulinoides beckmanni (Saito). Eclogae Geologicae Helvetiae. 63(3): 883-905. gs


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Globigerinatheka euganea compiled by the pforams@mikrotax project team viewed: 26-9-2020

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