Pearsonites anapetes


Classification: pf_cenozoic -> Truncorotaloididae -> Pearsonites -> Pearsonites anapetes
Sister taxa: P. anapetes, P. broedermanni, P. lodoensis,

Taxonomy

Citation: Pearsonites anapetes (Blow 1979)
Rank: Species
Basionym: Globorotalia (Acarinina) broedermanni anapetes
Synonyms:
Taxonomic discussion: Blow (1979, p. 914) distinguished this taxon from the ancestral broedermanni and viewed it as the terminal member of the convexa -broedermanni lineage. Aside from the specimens illustrated by Blow (1979, pl. 172) and the 9-chambered form from the G. lehneri Zone at DSDP 313 (Central Pacific) illustrated by Toumarkine (1975, pl. 2, figs. 17,18), we have not come across valid references to this form in the literature. The taxon is, however, moderately abundant in Tanzanian drill-cores that were recently taken near the type locality (Pearson and others, 2004). [Berggren et al. 2006]

Catalog entries: Globorotalia (Acarinina) broedermanni anapetes,

Type images:

Distinguishing features: Like I. broedermanni but with more plano-convex test; more chambers (8-9) in final whorl; wider and deeper umbilicus; and tendency towards an intraumbilically restricted aperture.

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: Distinguished from broedermanni by its more pronouncedly plano-convex test, larger number of chambers (8-9) in final whorl, wider, deeper umbilicus, and tendency towards an intraumbilically restricted aperture. [Berggren et al. 2006]

Wall type: Densely muricate, normal perforate, nonspinose. [Berggren et al. 2006]

Test morphology: Test low trochospiral, subcircular, weakly lobulate; in umbilical view 8-9 almost equidimensional, subtriangular chambers, intercameral sutures nearly straight, radial, moderately incised, umbilicus relatively broad and deep, aperture a continuous, circum-umbilical low arching slit (exposing earlier chambers in the umbilical region), extending towards (but not as far as) the peripheral margin, bordered by a thin lip; in spiral view about 18-20 chambers arranged in 2½ to 3 whorls, intercameral sutures flush with test, proximally radial, becoming retorse towards junction with peripheral margin; in edge view plano-convex; peripheral margin rounded to subacute with no evidence of peripheral concentration of muricae. [Berggren et al. 2006]

Size: Dimensions of holotype: maximum diameter: 0.32 mm (Blow, 1979, p. 914). [Berggren et al. 2006]

Character matrix

test outline:Subcircularchamber arrangement:Trochospiraledge view:Planoconvexaperture:Umbilical-extraumbilical
sp chamber shape:Inflatedcoiling axis:Lowperiphery:N/Aaperture border:Thin lip
umb chbr shape:Subtriangularumbilicus:Wideperiph margin shape:Narrowly roundedaccessory apertures:None
spiral sutures:Weakly depressedumb depth:Deepwall texture:Coarsely muricateshell porosity:Finely Perforate: 1-2.5µm
umbilical or test sutures:Weakly depressedfinal-whorl chambers:8.0-9.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Limited citation hinders determination of its geographic distribution; reported from East Africa and the north-west Pacific (see synonymy above); probably widely distributed in (sub)tropical areas of the world. [Berggren et al. 2006]
Aze et al. 2011 summary: Low to middle latitudes; based on Berggren et al. (2006a)

Isotope paleobiology: No data available. [Berggren et al. 2006]
Aze et al. 2011 ecogroup 1 - Open ocean mixed-layer tropical/subtropical, with symbionts. Based on very heavy δ13C and relatively light δ18O. Sources cited by Aze et al. 2011 (appendix S3): this study

Phylogenetic relations: Lineal descendant of Igorina broedermanni and apparently the end-member of the igorinid lineage. [Berggren et al. 2006]

Most likely ancestor: Pearsonites broedermanni - at confidence level 4 (out of 5). Data source: Berggren et al. (2006), f12.1.

Biostratigraphic distribution

Geological Range:
Notes: Zones E8-top of E9. We have also found in borehole TDP-13 in Tanzania (Pearson, P. N., personal observation) that anapetes has its LAD at the same level as Morozovella aragonensis (i.e., at the Zone E9/10 boundary). [Berggren et al. 2006]
Last occurrence (top): at top of E9 zone (100% up, 43.2Ma, in Lutetian stage). Data source: Berggren et al. (2006), f12.1
First occurrence (base): at base of E8 zone (0% up, 45.7Ma, in Lutetian stage). Data source: Berggren et al. (2006), f12.1

Plot of occurrence data:

Primary source for this page: Berggren et al. 2006 - Eocene Atlas, chap. 12, p. 380

References:

Berggren, W. A., Olsson, R. K. & Premoli Silva, I. (2006a). Taxonomy, biostratigraphy and phylogenetic affinities of Eocene Astrorotalia, Igorina, Planorotalites, and Problematica (Praemurica? lozanoi). In, Pearson, P. N. , Olsson, R. K. , Hemleben, C. , Huber, B. T. & Berggren, W. A. (eds) Atlas of Eocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication. 41: 377-400. gs

Bermudez, P. J. (1949). Tertiary smaller foraminifera of the Dominican Republic. Cushman Laboratory for Foraminiferal Research, Special Publication. 25: 1-322. gs

Blow, W. H. (1979). The Cainozoic Globigerinida: A study of the morphology, taxonomy, evolutionary relationships and stratigraphical distribution of some Globigerinida (mainly Globigerinacea). E. J. Brill, Leiden. 2: 1-1413. gs

Pearson, P. N. et al. (2004). Paleogene and Cretaceous sediment cores from the Kilwa and Lindi areas of coastal Tanzania: Tanzania Drilling Project Sites 1–5. Journal of African Earth Sciences. 39: 25-62. gs

Soldan, D. M., Petrizzo, M. R. & Silva, I. P. (2014). Pearsonites, a new Paleogene planktonic foraminiferal genus for the broedermanni lineage. Journal of Foraminiferal Research. 44: 17-27. gs

Toumarkine, M. & Luterbacher, H. (1985). Paleocene and Eocene planktic foraminifera. In, Bolli, H. M. , Saunders, J. B. & Perch-Neilsen, K. (eds) Plankton Stratigraphy. Cambridge Univ. Press, Cambridge 87-154. gs

Toumarkine, M. (1975). Middle and Late Eocene planktonic foraminifera from the northwestern Pacific Ocean: Leg 32 of the Deep Sea Drilling Project. Initial Reports of the Deep Sea Drilling Project. 32: 735-751. gs


logo

Pearsonites anapetes compiled by the pforams@mikrotax project team viewed: 17-7-2019

Taxon Search:
Advanced Search

Short stable page link: http://mikrotax.org/pforams/index.php?id=100172 Go to Archive.is to create a permanent copy of this page - citation notes



Comments (0)

No comments yet. Be the first!

Add Comment

* Required information
1000
Captcha Image
Powered by Commentics