Catalog - Globigerina baylissi

CATALOG OF ORIGINAL DESCRIPTIONS: Globigerina baylissi Samanta 1973

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 -> Globigerina -> Globigerina baylissi
Other pages this level: << < G. aspera, G. asperula, G. atlantica, G. atlantis, G. atlantisae, G. aumalensis, G. ayalai, G. azerbaidjanica, G. baconica, G. bacuana, G. bakeri, G. balchanensis, G. baroemoenensis, G. baroemoenensis quadrata, G. bathoniana, G. baylissi, G. belli, G. bermudezi, G. bilobata, G. binaiensis, G. bolivariana pannonica, G. bollii, G. bollii lentiana, G. boweri, G. bradyi, G. bramlettei, G. brazieri, G. brevis, G. brevispira, G. bulbosa, G. bulbosa trisphaera> >>

Globigerina baylissi

Citation: Globigerina baylissi Samanta 1973
Rank: Species
Type sample (& lithostrat): Types from sample No. 3622.
Type locality: Rakhi Nala section, W. Pakistan

Linked specimens: London, UK; NHM (PM P 48836)

Current identification:

Original Description

Diagnosis.- A Globigerina with a roughly triglobular, elongate, hispid test coiled in a low trochospire; a stongly inflated, radially elongate final chamber constitutes about ½ of the test; the moderately large, arched umbilical aperture is furnished with a narrow lip.

Description.- Test roughly triglobular, elongate, coiled in a low trochospire; ventral side more convex than the dorsal; equatorial periphery ovoid, elongate and strongly lobate; axial periphery rounded. Chambers inflated, globular and arranged in about 3 whorls; those in the initial whorl extremely small and tightly arranged; the last 3 chambers are large, strongly inflated and enlarge rapidly; the final chamber is radially elongate and consttitutes about ½ of the whole test; it often tends to be slightly displaced towards the ventral side. Sutures on the ventral side nearly straight, short and strongly depressed; on the dorsal side straight to slightly curved and moderately depressed. Umbilicus wide, open. Wall calcareous, finely perforate; surface weakly hispid. Aperture interio-marginal, umbilical, a moderately wide arched opening bordered with a narrow lip-like structure. 

Holotype: Maximum diameter 0.31 mm. Paratypes: Maximum diameter 0.28-0.30 mm.

The species is named after Dr D. D. Bayliss whose samples formed the basis of the present investigation.

Extra details from original publication
The main variation is in the shape of the dorsal side of the test, the degree of lobation of the periphery, the shape and size of the final chamber and the character of the aperture. The initial chambers in some specimens are depressed below the outer whorl. The aperture varies in size and often tends to extend outside the umbilicus; in most specimens, including the holotype, it is filled with crystalline material. The final chamber may be larger than the rest of the test. In well preserved specimens the umbilicus tends to reveal the apertures of the earlier chambers in the last whorl.

G. baylissi is readily distinguished from contemporaneous species of the genus by its elongate test and large, strongly inflated and radially elongate last chamber. However, it resembles Globigerina bulbosa Le Roy (originally described from the Middle Miocene of Sumatra), which species has more prominently elongate, bulbous later chambers.

G. baylissi seems to have been derived from G. inaequispira by the development of the elongate test, more rapidly enlarging chambers in the last whorl and radially elongate :final chamber, and transitional specimens were observed in the present material.

DISTRIBUTION. In the Rakhi Nala section Globigerina baylissi is restricted to the Truncorotaloides rohri Zone.

Editors' Notes


Samanta, B. K. (1973). Planktonic foraminifera from the Paleocene-Eocene succession in the Rakhi Nala, Sulaiman Range, Pakistan. Bulletin of the British Museum (Natural History) Geology. 22: 421-482. gs


Globigerina baylissi compiled by the pforams@mikrotax project team viewed: 6-12-2022

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