pforams@mikrotax - Pearsonites anapetes

pforams@mikrotax - Pearsonites anapetes pforams@mikrotax - Pearsonites anapetes

Pearsonites anapetes

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

Eocene_Atlas_pl12-2_fig15-16.jpg
Soldan et al 2011 f05-07.JPG
Soldan et al 2014 f05-03.JPG
Soldan et al 2011 f05-08.JPG
Soldan et al 2014 f07-03.JPG

Taxonomy

Citation: Pearsonites anapetes (Blow 1979)

taxonomic rank: Species

Basionym: Globorotalia (Acarinina) broedermanni anapetes

Synonyms:

Globorotalia broedermanni Cushman and Bermúdez.— Toumarkine, 1975:738, pl. 2: figs. 17, 18 [middle Eocene Globorotalia lehneri Zone, DSDP Site 313, Shatsky Rise, northwestern Pacific Ocean].—Toumarkine and Luterbacher, 1985:130, text-figs. 17-18 (reillustration of Toumarkine, 1975, pl. 2: figs. 17, 18); ?19 [ middle Eocene G. lehneri Zone, DSDP Site 305, Central Pacific Mountains, Central Pacific Ocean]. [Not Cushman and Bermúdez, 1949.]
Globorotalia (Acarinina) broedermanni anapetes Blow, 1979:914-915, pl. 172: figs. 1-5, 6 (holotype) [middle Eocene Zone P11, Sample RS.24, Kilwa area, Tanzania, East Africa].
Igorina anapetes (Blow)._Pearson and others, 2004:37, pl. 2, fig. 3 [middle Eocene, Zone P11, Tanzania Drilling Project Site 2, Kilwa Masoko, Tanzania]; Berggren et al. 2006, p. 380.

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:

holotype: G. (Acarinina) broedermanni anapetes
holotype: G. (Acarinina) broedermanni anapetes
paratype: G. (Acarinina) broedermanni anapetes
paratype: G. (Acarinina) broedermanni anapetes

Distinguishing features:
Parent taxon (Pearsonites): small Morozovellids with biconvex–planoconvex tests with an overall rounded periphery
This taxon: 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

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]

Wall type:

Soldan et al 2014 f05-3d.JPG
Soldan et al 2014 f05-3e.JPG
Soldan et al 2014 f07-3d.JPG
Soldan et al 2014 f08-d.JPG
Soldan et al 2014 f08-e.JPG

Densely muricate, normal perforate, nonspinose. [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: Subcircular chamber arrangement: Trochospiral edge view: Planoconvex aperture: Umbilical-extraumbilical
sp chamber shape: Inflated coiling axis: Low periphery: N/A aperture border: Thin lip
umb chbr shape: Subtriangular umbilicus: Wide periph margin shape: Narrowly rounded accessory apertures: None
spiral sutures: Weakly depressed umb depth: Deep wall texture: Coarsely muricate shell porosity: Finely Perforate: 1-2.5µm
umbilical or test sutures: Weakly depressed final-whorl chambers: 8-9 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 comparison with other species of the genus.

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:

Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
Histogram - Neptune occurrence data from DSDP and ODP proceedings. Pale shading <50 samples in time bin. Interpret with caution & read these notes
Taxon plotted: Pearsonites anapetes, synonyms included - Igorina anapetes;
See also space-time plot :: Samples map :: Parent: Pearsonites

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(Chap 12): 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. & Cau, A. (2011). Phylogenetic relationships and evolutionary history of the Paleogene genus through parsimony analysis. Journal of Foraminiferal Research. 41: 260-284. 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

Pearsonites anapetes compiled by the pforams@mikrotax project team viewed: 8-9-2024

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test outline:	Subcircular	chamber arrangement:	Trochospiral	edge view:	Planoconvex	aperture:	Umbilical-extraumbilical
sp chamber shape:	Inflated	coiling axis:	Low	periphery:	N/A	aperture border:	Thin lip
umb chbr shape:	Subtriangular	umbilicus:	Wide	periph margin shape:	Narrowly rounded	accessory apertures:	None
spiral sutures:	Weakly depressed	umb depth:	Deep	wall texture:	Coarsely muricate	shell porosity:	Finely Perforate: 1-2.5µm
umbilical or test sutures:	Weakly depressed	final-whorl chambers:	8-9	N.B. These characters are used for advanced search. N/A - not applicable