Globorotaloides


Classification: pf_cenozoic -> Globigerinidae -> Globorotaloides
Sister taxa: Beella, Globigerina, Globigerinella, Protentella, Quiltyella, Ciperoella, Globigerinoides, Globigerinoidesella, Globoturborotalita, Orbulina, Praeorbulina, Sphaeroidinella, Sphaeroidinellopsis, Trilobatus, Turborotalita, Dentoglobigerina, Globoquadrina, Catapsydrax, Clavatorella, Paragloborotalia, Protentelloides, Eoglobigerina, Globigerinatheka, Globorotaloides, Guembelitrioides, Orbulinoides, Parasubbotina, Pseudoglobigerinella, Subbotina,
Daughter taxa: (blue => in age window 0-300Ma)
stainforthi -> atlanticus lineage

Like G. stainforthi, but with an umbilical-to-equatorial bulla that extends around the peripheral margin, an equatorially directed primary aperture and more numerous chambers in the final whorl.


Test very low trochospiral, lobate; 4-5 chambers in the final whorl; umbilicus covered by a flattened bulla extending to the equatorial periphery with 3-5 small, rimmed, infralaminal accessory apertures, opening over sutures. 


other species
Test with 4½ to 6, final whorl chambers, increasing gradually in size.
Very low trochospiral, spiral side almost flat, equatorial periphery lobulate, chambers spherical
Test, small, lobulate test, 4-4½ chambers in final whorl, final chamber directed umbilically. Sacculifer-type wall texture.
Test low trochospiral, lobulate, axial periphery rounded; 4 to 5 chambers in final whorl; aperture a low arch, often covered by bulla-like final chamber.
Differs from other species of Globorotaloides by the more compact coiling, less lobate peripheral outline, a highly rugose wall, more restricted umbilicus and distinctly straight sutures.
Like G. suteri but with more compressed early chambers, more curved sutures, and more (5-6 vs 4-5) chambers in the final whorl.
Specimens which cannot be assigned to established species

Taxonomy

Citation: Globorotaloides Bolli, 1957
Rank: Genus
Type species: Globorotaloides variabilis Bolli, 1957.
Taxonomic discussion: Globorotaloides is a long-ranging genus that extends from the early Paleogene to the Recent. First described from the upper Miocene of Trinidad (Bolli, 1957), Globorotaloides is distinctive but easily overlooked because individuals are usually small, thus concentrated in smaller sieve fractions (<150 μm) and often rare, especially in the low to mid-latitudes (excluding upwelling zones). According to Bolli (1957), Globorotaloides combines characters of several genera having an initial “Globorotalia stage”, where the aperture is interiomarginal, umbilical-extraumbilical, a subsequent “Globigerina stage”, where the aperture becomes umbilical and a “terminal stage” involving growth of a bulla that covers the umbilical region. According to Bolli, Catapsydrax lacks the globorotaliid stage. Our taxonomy builds on this concept but also considers the flattened morphology of the spiral side.

Olsson and others (2006a) suggested that Globorotaloides quadrocameratus evolved from Parasubbotina in lower Eocene Zone E2. We, however, observe Globorotaloides-like morphologies in the early Paleocene, including specimens that have been illustrated as Subbotina cancellata and ‘Globigerina fringa Subbotina’ (see below), suggesting an earlier ancestry. Morphologies closely comparable to modern Globorotaloides hexagonus Natland, which is frequently found (at low abundance levels) in plankton nets, make their first appearance in the upper Oligocene.

The tendency for a bulla to develop in Globorotaloides appears to be dependent on geologic age. Early and early middle Eocene G. quadrocameratus and G. eovariabilis are typically non-bullate. Late Eocene, Oligocene and Miocene populations contain morphotypes with and without bulla. In contrast, Quaternary and living examples of Globorotaloides hexagonus (Natland) and Globorotaloides trema Lipps always lack a bulla. Reflecting on these observations, we have consolidated the set of described species, including one previously placed in Catapsydrax (i.e. stainforthi) to produce a framework through which the lineage to G. hexagonus can be traced. An important distinction, as originally set out by Bolli (1957), is that in Catapsydrax the aperture is umbilical whereas in Globorotaloides it is typically umbilical-extraumbilical, becoming equatorial in Globorotaloides atlanticus n. sp. and Protentelloides.

Globorotaloides maintained a low diversity through the early Oligocene but the group diversified in the mid- to late Oligocene (Figure 4.1). Development of the distinctive bullate morphospecies G. stainforthi was used as a zonal marker by Bolli (1957) for the early Miocene biozone bearing the name. Owing to the low abundance and patchy distribution of the nominate species the zone has not been incorporated into more recent ‘N’ or ‘M’ zonation schemes. Major modifications to the bulla in one branch of the lineage resulted in the evolution of the clavate planispiral genus Protentelloides. So far records of this genus are limited to the equatorial Atlantic Ocean.

An unresolved question underlying the taxonomy and phylogeny is whether Globorotaloides is spinose. Small circular holes occurring at the junction of cancellate ridges in some Eocene Globorotaloides quadrocameratus and Parasubbotina varianta have been interpreted as spine holes and therefore evidence that these taxa were spinose (Hemleben and Olsson, 2006, pl. 4.4, figs. 9, 12; Olsson and others, 2006a, pl. 5.5, fig. 8; pl. 5.13, figs. 15, 16). In core-top sediments (Holocene-Pleistocene) G. hexagonus occasionally also show similar ‘apparent spine holes’ supporting this idea. Living G. hexagonus recovered from plankton nets, however, clearly lack spines (Parker, 1962; Hemleben and others, 1989; Kucera, unpublished). Due to the close morphological similarities of wall and coiling in Paleogene and living Globorotaloides it seems unlikely that the genus is polyphyletic. Therefore, it is possible that spines were lost during the evolutionary transition from G. eovariabilis to G. hexagonus and/or that the holes are small pores or dissolution pits. For this reason we continue to separate G. eovariabilis and G. hexagonus, although we acknowledge the close morphologic similarity, and we note the continuous intergradation between the two in the mid- to late Oligocene. [Coxall & Spezzaferri 2018]

Catalog entries: Globorotaloides;

Type images:

Distinguishing features: Trochospiral test, ovate to spherical chambers; final chamber often small/bulla-like; cancellate wall.

NB These concise distinguishing features statements are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus.
They are being edited as the site is developed and comments on them are especially welcome.

Description


Diagnostic characters: Globorotaloides is distinguished from Parasubbotina and Catapsydrax by the Globorotalia-like flattened inner coil, the outer coil of globigeriniform chambers and the strongly cancellate wall texture with distinctly funnel shaped pores. The genus exhibits more evolute coiling, a flattened spiral side and typically has more chambers in the final whorl than Catapsydrax. Forms occur with and without bulla. [Coxall & Spezzaferri 2018]

Wall type: Spinose, normal perforate, coarsely cancellate, sacculifer-type to ruber/sacculifer-type wall texture. [Coxall & Spezzaferri 2018]

Test morphology: Low trochospiral, globular, lobulate, with 4-6 chambers in the final whorl; in spiral view the inner whorl of chambers has a “Globorotalia-like” flattened coil. Chambers become globular and more loosely coiled in the ultimate whorl; in umbilical view the ultimate chamber may be cantilevered towards the umbilicus; in edge view chambers globular, near spherical. The aperture is extraumbilical, bordered by thin continuous lip. A flattened bulla occurs in some species and within some populations of typically non-bullate forms; where present bullae may be umbilical, becoming extraumbilical to marginal in some upper Oligocene forms; there maybe one or more infralaminal aperture(s) that are bordered by a continuous narrow thickened lip or rim. There is a tendency to develop an imperforate peripheral band in some Eocene and early Oligocene forms. [Coxall & Spezzaferri 2018]

The genus Globorotaloides includes forms with a trochospiral test, ovate to spherical chambers, a final chamber that is often smaller than the penultimate and may cover part of or the entire umbilicus and appear almost indistinguishable from a bulla; a distinctly cancellate surface; and a primary aperture, which in the early stage is interiomarginal, umbilical-extraumbilical, later becoming umbilical. [Kennett & Srinivasan 1983]

Biogeography and Palaeobiology


Geographic distribution: Global in middle to low latitudes during the Eocene and Oligocene. Today, Globorotaloides (G. hexagonus) is described as an “Indo-Pacific species”, having reportedly become extinct in the Atlantic approximately 60,000 years ago B.P. (Pflaumann, 1986; Kucera and others, 2005). [Coxall & Spezzaferri 2018]

Phylogenetic relations: The genus was probably derived from a heavily cancellate subbotinid in the early Paleocene. Globorotaloides likely gave rise to Catapsydrax in the early Eocene.  [Coxall & Spezzaferri 2018]

Globorotaloides is one of the long-ranging genera of the Cenozoic. The earliest member, Globorotaloides suteri, appeared during the Late Eocene. In the Neogene, the genus is represented by the Gd. suteri-Gd. variabilis-Gd. hexagona lineage (Text Fig. 24), although this is one of the least understood Neogene planktonic foraminiferal lineages. [Kennett & Srinivasan 1983]

Most likely ancestor: Parasubbotina - at confidence level 1 (out of 5). Data source: Coxall & Spezzaferri 2018 - they suggest P. varianta as the likely ancestor of G. quadrocameratus.

Biostratigraphic distribution

Geological Range:
Notes: Early Paleocene? to Recent [Coxall & Spezzaferri 2018]
Last occurrence (top): Extant Data source: Total of range of species in this database
First occurrence (base): at base of Ypresian Stage (2% up, 55.8Ma, in Ypresian stage). Data source: Total of range of species in this database

Plot of occurrence data:

Primary source for this page: Coxall & Spezzaferri 2018 - Olig Atlas chap.4 p.92 (major revison of Olsson et al. 2006 - Etc Atlas chap.5, p.79); Kennett & Srinivasan 1983, p.213

References:

Bolli, H.M., (1957). Planktonic foraminifera from the Oligocene-Miocene Cipero and Lengua formations of Trinidad, B.W.I. In: Loeblich, A.R., Jr. et al. (Editors), Studies in Foraminifera: U.S. National Museum Bulletin 215. U.S. Government Printing Office, Washington, DC, pp. 97-123.

Coxall, H.K. & Spezzaferri, S., (2018). Taxonomy, biostratigraphy, and phylogeny of Oligocene Catapsydrax, Globorotaloides, and Protentelloides. In: Wade, B.S. et al. (Editors), Atlas of Oligocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research Special Pulbication. 46, pp. 79-125.

Kennett, J.P. & Srinivasan, M.S., (1983). Neogene Planktonic Foraminifera. Hutchinson Ross Publishing Co., Stroudsburg, Pennsylvania, 1-265 pp.

Olsson, R.K.; Pearson, P.N. & Huber, B.T., (2006). Taxonomy, biostratigraphy, and phylogeny of Eocene Catapsydrax, Globorotaloides, Guembelitrioides, Paragloborotalia, Parasubbotina, and Pseudoglobigerinella n. gen. In: Pearson, P.N. et al. (Editors), Atlas of Eocene Planktonic Foraminifera. Cushman Foundation Special Publication. 41 Allen Press, Lawrence, Kansas, pp. 67-110.


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Globorotaloides compiled by the pforams@mikrotax project team viewed: 12-11-2018

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Short stable page link: http://mikrotax.org/pforams/index.php?id=100134Go to Archive.is to create a permanent copy of this page - citation notes



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