Acarinina cuneicamerata Blow 1979 (TaxonConcept

Anonymous: Unedited TaxonConcept data

Notice: This catalogue page may contain unedited data.

Species Acarinina cuneicamerata Blow 1979

Diagnosis / Definition:

Pearson et al. (2006):
DESCRIPTION. Type of wall: Densely muricate, nonspinose, normal perforate. Test morphology: Low trochospiral, 5-6 moderately inflated, strongly muricate chambers in last whorl; margins of later chambers in final whorl exhibit tendency to develop angulate and disjunct chamber separation in some individuals; sutures straight, radial, depressed to moderately incised; umbilicus wide, deep, relict apertures of ante- and penultimate chambers visible within umbilical area and bordered by distinct, circumumbilically extending apertural lip(s) connecting to the relatively broad lip of the final chamber; no circumumbilical concentration of muricae; aperture umbilical-extraumbilical, extending towards, but not reaching the periphery; spiral side weakly muricate, about 12, flattened chambers arranged in relatively involute spire of 2 whorls; minute, discrete openings observable, at suture/chamber junctions on well preserved specimens; sutures straight to weakly curved and tangential to periphery; chambers of last whorl lunate with ante- and penultimate chamber often wedge-shaped (cuneiform); in edge view umbilical side is anguloconical with rounded to subacute peripheral margin; spiral side flat. Size: Diameter of holotype 0.41 mm.

Discussion / Comments:

Pearson et al. (2006):
DISTINGUISHING FEATURES.- This form is distinguished by its combination of subtriangular to wedge-shaped (cuneiform) and lunate chambers, tendency to develop laterally angulate and peripherally disjunct terminal chambers, widely open umbilicus, and densely muricate umbilical side and only weakly muricate spiral side. DISCUSSION.- This taxon was described by Blow (1979) for predominantly 5-6 chambered (in the final whorl), loosely coiled, muricate forms that exhibit a tendency to develop laterally angulate, disjunct terminal chambers and a relatively wide open umbilicus. He drew attention to the potential confusion in distinguishing 6- 8 chambered forms from the stratigraphically coeval A. aspensis but noted that the smoothly rounded chamber margins (absence of lateral angularity) of aspensis serve to distinguish it from cuneicamerata. The FAD of A. cuneicamerata has recently been calibrated to Chron C22r at -50.4 Ma by Hancock and others (2002) at ODP Hole 762C, Exmouth Plateau, north-west Australian margin at essentially the same (estimated) level of the FAD of (the elusive) Planorotalites palmerae which has been used to denote the top of Zone P8 (=Zone E6 of this paper). Accordingly the FAD of this taxon has been used to denote the base of Zone E6 in the recently revised Eocene zonation (Berggren and Pearson, 2005). The little known taxon Globorotalia berwaliana Mohan and Soodan may be a senior synonym. PHYLOGENETIC RELATIONSHIPS.- Probably evolved from Acarinina angulosa and left no descendants. STRATIGRAPHIC RANGE.- Zone E6 (base, by definition) to Zone E9 (lower part) (Blow 1979; Hancock and others, 2002). GEOGRAPHIC DISTRIBUTION.- Equatorial Atlantic Ocean, Tethyan region (Egypt) and Indian Ocean. STABLE ISOTOPE PALEOBIOLOGY.- Probably recorded by Boersma and others (1987) (as A. pentacamerata) with negative ò18O indicating a surface water habitat. Pearson and others (2001) recorded it with the most negative ò18O of a large suite of middle Eocene species.

Systematics:

35
Ordo Foraminiferida
  Superfamilia Globigerinaceae
   Familia Truncorotaloididae
    Genus Acarinina
     Species Acarinina cuneicamerata

Synonym list:

Pearson et al. (2006):

? 1969 Globorotalia berwaliana Mohan & Soodan. - Mohan & Soodan : p. 9-10 pl. 1a-f [Middle Eocene Globigerinoides kugleri - Globigerina frontosa Assemblage Zone, Benvali Stream, Kutch, India]

p 1979 Globorotalia (Acarinina) cuneicamerata Blow. - Blow : p.924 pl. 146, fig. 6-8 [Zone P9, DSDP Site 47, Shatsky Rise, north-west Pacific Ocean]; pl. 153, fig. 1-4 [Zone P9, KANE 9, piston core 42, Endeavour Seamount, equatorial Atlantic Ocean]; pl. 156, fig. l , 2 (holotype), 3-4; pl. 203, fig. 5; detail of pl. 146: fig. 5 (given erroneously as detail of pl. 156: fig. 6); pl. 165: figs. 4 and 7 [Zone P10, KANE 9, piston core 42,95 cm; Endeavour Seamount, equatorial Atlantic Ocean]

1979 Globorotalia (Acarinina) sp. . - Blow : p.924 pl. 154; fig. 6, 7 (Globorotalia (Acarinina) sp. ex interc. G. (A.). decepta (Martin) and G. (A.) cuneicamerata n.sp. Blow, 1979); [Zone P10, KANE 9, piston core 42,95 cm; Endeavour Seamount, equatorial Atlantic Ocean].

2006 Acarinina cuneicamerata Blow. - Pearson et al. : p.281 pl. 9.9; fig. 1-16 (Pl. 9.9, Figs. 1-4, 8: reillustration of holotype and paratypes of Globorotalia (Acarinina) cuneicamerata Blow)

Specimen:

Natural History Museum, London, Inventory number: BP 60/3

References:

Mohan,M.. and Soodan,K.S.. (1969):
Two new Lutetian species of Rotaliina from Kutch . Journal of the Palaeontological Society of India Vol. 12 p. 9-11

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

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

This work is licensed under a Creative Commons Attribution 2.5 License.

Back to Search

Taxon relations
pdf
Ranking (experimental)

Taxon Concept provided by
Home \| Search