CATALOG OF ORIGINAL DESCRIPTIONS: Praehedbergella subsp. ruka contritus Banner et al. 1993

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 -> P -> Praehedbergella -> Praehedbergella ruka contritus
Other pages this level: P. grigelisae, P. grigelisi perforare, P. pseudosigali, P. ruka, P. ruka contritus, P. ruka papillata, P. ruka ruka, P. sigali compacta, P. sigali rasilis, P. tatianae,

Praehedbergella ruka contritus

Citation: Praehedbergella subsp. ruka contritus Banner et al. 1993
Rank: sub-species
Type locality: Central North Sea Well16/28-6RE, (3989.5 m).
Type age: Late Aptian
Holotype Repository: London, UK; NHM
Type & figured specimens: Holotype. P52737,Paratype. P52738

Linked specimens: London, UK; NHM (52738) London, UK; NHM (PM PF 52737)

Current identification/main database link: Hedbergella ruka (Banner, Copestake and White, 1993)

Original Description
Characterized by its high trochospire, strong dorsal convexity, depressed chambers (excluding the last) in the final whorl (about half as high as long when viewed spirally), and a smooth test surface lacking perforation cones. The final chamber may be subglobular.

Etymology: After contritus, a worn down object, referring to the depressed chambers in the last whorl.

Extra details from original publication
REMARKS. The specimens of P. ruka figured by Caron (1978) came from beds she believed to be upper Aptian and r which were in the lowest core obtained from DSDP Site 364, I Angola Basin; unfortunately, she misidentified it as 'Hedbergella infracretacea gargasiana Moullade', a form which has high, undepressed chambers in the final whorl, and which is referable either to Blefuscuiana or to Hedbergella (with a muricate test surface). The only resemblance between P. ruka and Moullade's form is the great convexity of the dorsal side. The holotype of P. ruka contritus occurred in the Upper Aptian but it may be reworked there; we have not seen 1 evidence for its occurrence in beds of Late Aptian age I elsewhere. We suspect that the earliest cores retrieved from DSDP Site 364 were, in fact, of Early Aptian age.
A similar form has been figured by Crittenden (1982) from the Atherfield Clay (Early Aptian) of the Isle of Wight southern England. He called it 'Hedbergella hoterivica', but that species belongs to the genus Favusella (Banner & Desai, 1988); Crittenden's specimens posses a high spire and dorsal convexity, and lack perforation-cones, but their re-examination is necessary before identity with this subspecies is confirmed.
DISTRIBUTION. Angola Basin and Walvis Ridge, southeastern Atlantic Ocean; Central North Sea; ?southern England.
STRATIGRAPHY. Early-?Late Aptian.


Banner, F. T., Copestake, P. & White, M. R. (1993). Barremian-Aptian Praehedbergellidae of the North Sea area: a reconnaisance. Bulletin of the Natural History Museum, London (Geology). 49: 1-30. gs :: ::


Praehedbergella ruka contritus compiled by the pforams@mikrotax project team viewed: 14-7-2020

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