Catalog - Mutabella mirabilis

CATALOG OF ORIGINAL DESCRIPTIONS: Mutabella mirabilis Pearson et al. 2001

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 -> M -> Mutabella -> Mutabella mirabilis
Other pages this level: M. mirabilis

Mutabella mirabilis

Citation: Mutabella mirabilis Pearson et al. 2001
Rank: Species
Type specimens: Holotype USNM 510205 and paratypes 510206-510223.
Type sample (& lithostrat): ODP 144-872A- 10H-6, 59-61 cm
Type age (chronostrat): Biozone M3/4 ( N6/7)
Type locality: ODP Hole 872A, Lo-En Guyot, Marshall Islands region, west Pacific Ocean (10.1N; 162.87E;).
Type repository: Washington, USNM

Linked specimens: USNM-510215 USNM-510208 USNM-510207 USNM-510211 USNM-510220 USNM-510222 USNM-510210 USNM-510212 USNM-510221 USNM-510205 USNM-510216 USNM-510209 USNM-510213 USNM-510206 USNM-510223 USNM-510214 USNM-510217 USNM-510219 USNM-510218

Current identification/main database link: Mutabella mirabilis Pearson, Norris & Empson 2001

Original Description

The test is comprised of 12 or 13 chambers arranged in a low sinistral trochospiral with about 4 1⁄3 chambers in the last whorl. Chambers are subglobular and slightly radially compressed except for the last chamber, which is almost spherical. Chambers expand fairly rapidly in size, such that the final chamber is about twice as wide as the first full chamber in the final whorl. Sutures on both sides of the test are depressed and radial with a slight degree of curvature. The aperture is a low, broad asymmetrical arch, situated in an intra-extraumbilical position. It is covered by an irregular tooth-plate, which is a composite structure formed by the fusion of the apertural lips of the final and penultimate chambers. The wall texture is microperforate and pustulose, and appears slightly translucent under the light microscope. Pustules are about 2-5 µm in diameter at their base and tend to be conical or tetrahedral. They are more prominent on the earlier chambers of the final whorl, becoming progressively smaller and less angular on later chambers. The final chamber lacks distinct pustules except in proximity to the apertural tooth-plate. The proloculus and first two or three chambers are obscured by smooth superficial calcification. Pores are distributed irregularly, but not strictly randomly, between the pustules. A single circular perforation, with a diameter of about 10 µm is present at the base of the final suture on the spiral side, and may represent a minute supplementary aperture.

The maximum diameter is 260 µm; the minimum diameter is 195 µm

Latin ‘‘mirabilis’’ wonderful or strange

Extra details from original publication
Morphological variability. The extraordinary feature of M. mirabilis is the high level of intraspecific variation. The holotype is a relatively ‘‘conservative’’ specimen. Some aspects of the morphological variability are examined in the morphometric study reported below. Other aspects are best explained with reference to the illustrated paratype specimens on Plates 2–4.

Stratigraphic Range. Probably from Zone M3 (lower Miocene) to Zone M7 (middle Miocene) (see discussion below)

Editors' Notes


Pearson, P. N., Norris, R. D. & Empson, A. (2001b). Mutabella mirabilis gen. et sp. nov., a Miocene microperforate planktonic foraminifer with an extreme level of intraspecific variability. Journal of Foraminiferal Research. 31: 120-132. gs


Mutabella mirabilis compiled by the pforams@mikrotax project team viewed: 30-9-2022

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