Catalog - Helvetiella atlantica

CATALOG OF ORIGINAL DESCRIPTIONS: Helvetiella atlantica Longoria and Gamper 1984

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 -> H -> Helvetiella -> Helvetiella atlantica
Other pages this level: H. atlantica, H. helvetia

Helvetiella atlantica

Citation: Helvetiella atlantica Longoria and Gamper 1984
Rank: Species
Described on page(s) : 175
Type sample (& lithostrat): DSDP Leg 39 Site 356-30-1, 140-142cm
Type age (chronostrat): Late Maaslrichlian. Abathomphalus mayaroensis- Giobigerina eugubina lntervai-Zone
Type locality: NW Atlantic, Orphan Knoll, DSDP Site 356
Type repository: USNM

Current identification/main database link: Kuglerina rotundata (Bronnimann, 1952)


Original Description

Diagnosis: Helvetiella with plano·convex test, four to five chambers in last whorl: gerontic specimens may develop dorsal rim in ultimate chamber formed by agglomeration of papillae.

Description: Test medium-sized, lobulated, plano-convex to concavo-convex, umbilical side strongly inflated. Early whorls flattened, final whorl concave, generally with four to five chambers; early chambers inflated on both spiral and umbilical sides, final chamber flattened on dorsal side, often possessing ring formed by aggregation of massive papillae or spines, inflated on umbilical side. Sutures strongly depressed, straight on both spiral and umbilical sides. Umbilicus wide, deep, covered by tegilla.

Size:

Etymology:
Helvetiella atlantica is named for the Atlantic Ocean, where it was found.

Extra details from original publication
Remarks: Helvetiella atlantica is distinguished from H. helvetia by its concavo-convex test with four to five globular chambers in the last whorl. These features easily separate it from other species of Helvetie/la. lt differs from Bucherina arabica (EI-Naggar) by: 1) its smaller test, formed by two rather than three whorls; 2) having inflated rather than flattened chambers spirally; and 3) lacking a shift in the axial piane of coiling.

Variation of the species: fifty·five specimens of Helvetiella atlantica were analyzed. This species is quite uniform and shows little morphologic variation. Neanic specimens do not display the dorsal rim often observed in the ultimate chamber of ephebic individuals. Although concavo-convex specimens are more frequent, eight specimens with plano-convex tests were observed. A constant character is the spiny (hispid) ornamentation, which was observed in all the chambers of the last whorl.

Range. Late Maastrichtian. Abathomphalus mayaroensis- Giobigerina eugubina lnterval-Zone.

Editors' Notes

References:

Longoria, J. F. & Gamper, M. A. (1984). Subfamily Helvetiellinae, a new group of Late Cretaceous (Maastrichtian) planktonic foraminifera. Micropaleontology. 30: 171-179. gs


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Helvetiella atlantica compiled by the pforams@mikrotax project team viewed: 5-12-2022

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