Taxon Concept provided by
  Home |   Search

Click on a letter below to get a list of species:
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z all
Igorina anapetes Blow 1979 from: Pearson, P.N.Olsson, R.K.Hemleben, C.Huber, B.T.Berggren, W.A. (2006): Atlas of Eocene Planktonic Foraminifera. p. 1-513
.
Anonymous: Unedited TaxonConcept data
Notice: This catalogue page may contain unedited data.

Species Igorina anapetes Blow 1979


Diagnosis / Definition:
Pearson et al. (2006):
DESCRIPTION. Type of wall: Densely muricate, normal perforate, nonspinose. 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 unlbilical 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 2 1/2-3 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. Size: Dimensions of holotype: maximum diameter: 0.32 mm (Blow, 1979, p. 914).
Discussion / Comments:
Pearson et al. (2006):
DISTINGUISHING FEATURES.- 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. DISCUSSION.- Blow (1 979, 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 3 13 (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). PHYLOGENETIC RELATIONSHIPS.- Lineal descendant of Igorina broedermanni and apparently the end-member of the igorinid lineage. STRATIGRAPHIC RANGE.- 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 E9110 boundary). 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. STABLE ISOTOPE PALEOBIOLOGY.- No data available.
Systematics:

35
 Ordo Foraminiferida
  Superfamilia Globigerinaceae
   Familia Truncorotaloididae
    Genus Igorina
     Species Igorina anapetes
Synonym list:
Pearson et al. (2006):
1975 Globorotalia broedermanni Cushman & Bermudez. - Toumarkine : p.738 pl. 2; fig. 17, 18 [middle Eocene Globorotalia lehneri Zone, DSDP Site 3 13, Shatsky Rise, northwestern Pacific Ocean]
1979 Globorotalia (Acarinina) broedermanni anapetes Blow. - Blow : p. 914-915 pl. 172; fig. 1-5, 6 (holotype) [middle Eocene Zone PI 1, Sample RS.24, Kilwa area, Tanzania, East Africa]
1985 Globorotalia broedermanni Cushman & Bermudez. - Toumarkine & Luterbacher : p.130 text-fig. 17-1 8 (reillustration of Toumarkine, 1975, pl. 2: figs. 17, I S); ?l9 [middle Eocene G. lehneri Zone, DSDP Site 305, Central Pacific Mountains, Central Pacific Ocean]; [Not Cushman and Bermudez, 1949]
2004 Igorina anapetes Blow. - Pearson et al. : p.37 pl. 2; fig. 3 [middle Eocene, Zone P 11, Tanzania Drilling Project Site 2, Kilwa Masoko, Tanzania]
2006 Igorina anapetes Blow. - Pearson et al. : p.383 pl. 12.2; fig. 13-16
Specimen:
Micropaleontological Collections - British Museum of Natural History, Inventory number: BP 62/3
References:

Toumarkine,M. (1975):
Middle and Late Eocene planktonic foraminifera from the northwestern Pacific, Leg 32 of the Deep Sea Drilling Project.
In: Initial Reports of the Deep Sea Drilling Project Vol. 32 Eds: Larson, R.L.Moberly, R. p. 735-751

Blow,W.H. (1979):
The Cainozoic Globigerinida. 3 Vols p. 1413 pp

Toumarkine,M. and Luterbacher,H.P. (1985):
Paleocene and Eocene Planktic Foraminifera.
In: Plankton Stratigraphy p. 87-154

Pearson,P.N.; Nicholas,C.J..; Singano,J.M..; Bown,P.R..; Coxali,H.K..; van Dongen,B.E..; Huber,B.T.; Karega,A..; Lees,J.A..; Misaky,E..; Pancost,R.D..; Pearson,M.. and Roberts,A.P.. (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 Vol. 39 p. 25-62

Pearson,P.N.; Olsson,R.K.; Hemleben,C.; Huber,B.T. and Berggren,W.A. (2006):
Atlas of Eocene Planktonic Foraminifera. p. 1-513
Anonymous: Unedited TaxonConcept data
Creative Commons Attribution 2.5 License
This work is licensed under a Creative Commons Attribution 2.5 License.