Pearsonites broedermanni


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

Taxonomy

Citation: Pearsonites broedermanni (Cushman & Bermudez 1949)
Rank: Species
Basionym: Globorotalia (Truncorotalia) broedermanni
Synonyms:
Taxonomic discussion: This (predominantly) Eocene taxon figures prominently in early and early middle Eocene (sub)tropical assemblages. It may be considered the central form of the “Morozovella broedermanni group” (Premoli Silva and Boersma, 1988, p. 344) which is closely related to, and descended from, the group of “biconvex morozovellids” (Premoli Silva and Boersma, 1988: 344), characterized by Igorina convexa/ tadjikistanensis and related forms (see also Premoli
Silva and Boersma, 1989; Blow, 1979, p. 934). Pearson (1993, p. 20; text-fig. 14) included broedermanni in the group of “biconvex morozovellids” ( “Acarinina pusilla group”) recognizing that it (and related forms) was probably not referable to either Morozovella or Acarinina. Berggren and Norris (1997) included these forms in Igorina (see also Olsson and others, 1999 for further discussion).
Blow (1979) distinguished Globorotalia broedermanni lodoensis Mallory (from the lower Eocene part of the Lodo Fm. of California) as a lower Eocene (Zone P5-P8b) ancestor of broedermanni s. str., which was said to range from Zone P8a to P11 (=Zone E5-9 of this paper). Distinction between the two was based upon subtle (but distinct) differences such as: usually lower number of chambers in last whorl, relatively more tightly coiled test resulting in narrower umbilicus, more smoothly recurved dorsal intercameral sutures and more lobulate periphery (lodoensis) vs proximally more radial but marginally/distally sharply retorse sutures, more evolute coiling resulting in somewhat larger umbilicus particularly in younger forms, slightly more inflated chambers ventrally and dorsally in some instances, somewhat more equally biconvex and greater appression of chambers in the last convolution of the test, and slightly more tightly coiled test (broedermanni; see further discussion under lodoensis below).
We have observed that Igorina broedermanni evolved from I. lodoensis in the middle part of (former) Zone P5, just below the Paleocene Eocene Thermal Maximum (PETM) in the Dababiya, Qreiya and Owaina sections of Egypt and in the Bass River borehole of the New Jersey Coastal Plain. It occurs relatively commonly in the middle to upper part of the Esna Shale Fm. (Zones P6 and P7= Zones E3-5) at Dababiya and other sections in Egypt. In the PETM interval, the chambers on the umbilical side of individuals of broedermanni are relatively weakly inflated; it is only above the Carbon Isotope Excursion/PETM (i.e., above Zone E1) that the chambers exhibit an inflational tendency, the test becomes distinctly umbilico-convex and the taxon broedermanni assumes its typical appearance.
Included by us in broedermanni are the taxa Globorotalia mattseensis and Globorotalia wartsteinensis of Gohrbandt (1967) and Acarinina planodorsalis of Fleisher (1974). Together, these taxa illustrate a gradual morphologic trend in middle Eocene Igorina broedermanni towards increasing number of chambers in the final whorl and flattening of the dorsal side that culminates in the evolution of Igorina anapetes. [Berggren et al. 2006]

Catalog entries: Globorotalia (Truncorotalia) broedermanni, Acarinina planodorsalis, Globorotalia mattseensis, Globorotalia wartsteinensis

Type images:

Distinguishing features: Biconvex to planoconvex test with 6-7 chambers in fine whorl. Like I. lodoensis but with less lobulate periphery and flatter spiral side.

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: Characterized by bluntly muricate, weakly biconvex to planoconvex test, rounded (noncarinate) periphery and narrow umbilicus; distinctly curved to retorse sutures on spiral side. Distinguished from I. lodoensis by its less lobulate periphery and flatter spiral side, and from I. anapetes by having fewer chambers in the final whorl and a narrower umbilicus. [Berggren et al. 2006]

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

Test morphology: Test low trochospiral, subcircular, weakly lobulate outline, planoconvex to weakly biconvex, blunt-tipped muricae covering both sides of test; in umbilical view involute, 6-7 essentially equidimensional, broadly triangular-shaped chambers, sutures depressed, radial, umbilicus narrow, deep, bordered by coalescing circumumbilical muricate, triangular chamber tips, aperture a low slit extending towards peripheral margin; in spiral view about 11-12 chambers in 2½ whorls gradually increasing in size in an evolute coil, broadly subquadrate to subrectangular in shape, intercameral sutures curved and retorse at junction with peripheral margin, planoconvex to weakly biconvex; in edge view, rounded to subangular, noncarinate. [Berggren et al. 2006]

Size: dimensions of holotype: length: 0.33 mm; breadth: 0.28 mm; thickness: 0.18 mm (Cushman and Bermudez, 1949, p. 40). [Berggren et al. 2006]

Character matrix

test outline:Subcircularchamber arrangement:Trochospiraledge view:Planoconvexaperture:Umbilical
sp chamber shape:Subrectangularcoiling axis:Lowperiphery:Muricocarinateaperture border:N/A
umb chbr shape:Subtriangularumbilicus:Narrowperiph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:Flushumb depth:Deepwall texture:Moderately muricateshell porosity:Finely Perforate: 1-2.5µm
umbilical or test sutures:Weakly depressedfinal-whorl chambers:6.0-7.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Widespread in Caribbean (Cuba, Trinidad), Atlantic and Indo-Pacific realms as well as in Tethys (Syria, Egypt, Tunisia, Senegal, Yugoslavia, Italy), Caucasus regions. Krasheninnikov (1974, p. 121) noted that broedermanni occurs in the Atlantic (Sites 6, 19, 20, 21, 22), Pacific (Sites 47, 162, 200) and Indian (Sites 219, 223) Oceans. It has not been reliably reported from high southern (austral) latitudes according to our information. [Berggren et al. 2006]
Aze et al. 2011 summary: Low to middle latitudes; based on Berggren et al. (2006a)

Isotope paleobiology: Recorded by Pearson and others (1993) (as ‘Morozovellabroedermanni) and Pearson and others (2001) as a surface mixed-layer species with very positive ∂13C indicating a mixed layer symbiotic habitat. [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): Pearson et al. (1993, 2001a)

Phylogenetic relations: Descended from Igorina lodoensis and evolved into I. anapetes by increase in number of chambers. [Berggren et al. 2006]

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

Biostratigraphic distribution

Geological Range:
Notes: Just below E1 to top of Zone E9. [Berggren et al. 2006]
Last occurrence (top): in upper part of E9 zone (80% up, 43.4Ma, in Lutetian stage). Data source: Berggren et al. (2006), f12.1
First occurrence (base): in upper part of P5 zone (80% up, 56.2Ma, in Thanetian 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. 384

References:

Berggren, W. A. & Norris, R. D. (1997). Biostratigraphy, phylogeny and systematics of Paleocene trochospiral planktonic foraminifera. Micropaleontology, Supplement 1. 43: 1-116. gs

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

Bermudez, P. J. (1961). Contribucion al estudio de las Globigerinidea de la region Caribe-Antillana (Paleoceno-Reciente). Editorial Sucre, Caracas. 1119-1393. 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

Bolli, H. M. (1957a). Planktonic foraminifera from the Eocene Navet and San Fernando formations of Trinidad. In, Loeblich, A. R. , Jr. , Tappan, H. , Beckmann, J. P. , Bolli, H. M. , Montanaro Gallitelli, E. & Troelsen, J. C. (eds) Studies in Foraminifera. U.S. National Museum Bulletin. 215: 155-172. gs

Bolli, H. M. (1957d). The genera Globigerina and Globorotalia in the Paleocene-Lower Eocene Lizard Springs Formation of Trinidad. In, Loeblich, A. R. , Jr. , Tappan, H. , Beckmann, J. P. , Bolli, H. M. , Montanaro Gallitelli, E. & Troelsen, J. C. (eds) Studies in Foraminifera. U.S. National Museum Bulletin. 215: 61-82. gs

Cifelli, R. & Belford, D. J. (1977). The Types of Several Species of Tertiary Planktonic Foraminifera in the Collections of the U.S. National Museum of Natural History. Journal of Foraminiferal Research. 7: 100-105. gs

Cushman, J. A. & Bermudez, P. J. (1949). Some Cuban species of Globorotalia. Contributions from the Cushman Laboratory for Foraminiferal Research. 25: 26-45. gs

Fleisher, R. L. (1974a). Cenozoic planktonic foraminifera and biostratigraphy, Arabian Sea, Deep Sea Drilling Project, Leg 23A. Initial Reports of the Deep Sea Drilling Project. 23: 1001-1072. gs

Gohrbandt, K. H. A. (1967). Some new planktonic foraminiferal species from the Austrian Eocene. Micropaleontology. 13(3): 319-326. gs

Krasheninnikov, V. A. (1974). Nekotoryie vidy planktonnykh foraminifer iz eotsovykh oligotsenovykh otlozhenii yuzhnoi armenii. Voprosy Mikropaleontologii. 17: 95-135. gs

Lu, G. & Keller, G. (1995). Planktic foraminiferal faunal turnovers in the subtropical Pacific during the Late Paleocene to Early Eocene. Journal of Foraminiferal Research. 25: 97-116. gs

Olsson, R. K., Hemleben, C., Berggren, W. A. & Huber, B. T. (1999). Atlas of Paleocene Planktonic Foraminifera. Smithsonian Institution Press, Washington, DC. 1-252. gs

Pearson, P. N. (1993). A lineage phylogeny for the Paleogene planktonic foraminifera. Micropaleontology. 39: 193-232. gs

Pearson, P. N., Shackleton, N. J. & Hall, M. A. (1993). Stable isotope paleoecology of middle Eocene planktonic foraminifera and multi-species isotope stratigraphy, DSDP Site 523, South Atlantic. Journal of Foraminiferal Research. 23: 123-140. 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

Postuma, J. A. (1971). Manual of planktonic foraminifera. Elsevier for Shell Group, The Hague. 1-406. gs

Premoli Silva, I. & Boersma, A. (1988). Atlantic Eocene planktonic foraminiferal historical biogeography and paleohydrographic indices. Palaeogeography, Palaeoclimatology, Palaeoecology. 67: 315-356. gs

Premoli Silva, I. & Boersma, A. (1989). Atlantic Paleogene planktonic foraminiferal bioprovincial indices. Marine Micropaleontology. 14: 357-371. gs

Pujol, C. (1983). Cenozoic planktonic foraminiferal biostratigraphy of the South-Western Atlantic (Rio Grande Rise): Deep Sea Drilling Project Leg 72. Initial Reports of the Deep Sea Drilling Project. 72: 623-673. gs

Said, R. & Sabry, H. (1964). Planktonic foraminifera from the type locality of the Esna Shale in Egypt. Micropaleontology. 10: 375-395. gs

Snyder, S. W. & Waters, V. J. (1985). Cenozoic planktonic foraminiferal biostratigraphy of the Goban Spur Region, Deep Sea Drilling Project Leg 80. Initial Reports of the Deep Sea Drilling Project. 80: 439-472. 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

Stainforth, R. M., Lamb, J. L., Luterbacher, H., Beard, J. H. & Jeffords, R. M. (1975). Cenozoic planktonic foraminiferal zonation and characteristics of index forms. University of Kansas Paleontological Contributions. 62: 1-425. 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

Warraich, M. Y. & Ogasawara, K. (2001). Tethyan Paleocene-Eocene planktic foraminifera from the Rakhi Nala and Zinda Pir land sections of the Sulaiman Range, Pakistan. Science Reports of the Institute of Geosciences, University of Tsukuba, Section B = Geological Sciences. 22: 1-59. gs

Warraich, M. Y., Ogasawara, K. & Nishi, H. (2000). Late Paleocene to early Eocene planktic foraminiferal blostratigraphy of the Dungan Formation, Sulaiman Range, central Pakistan. Paleontological Research. 4(4): 275-301, 218 figures, 273 aendices. gs


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Pearsonites broedermanni compiled by the pforams@mikrotax project team viewed: 18-10-2019

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