Turborotalia altispiroides Bermudez 1961 from: Pearson, P.N.Olsson, R.K.Hemleben, C.Huber, B.T.Berggren, W.A. (2006): Atlas of Eocene Planktonic Foraminifera. p. 1-513 . |
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Species Turborotalia altispiroides Bermudez 1961 |
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Diagnosis / Definition: |
Pearson et al. (2006):
DESCRIPTION.
Type of wall: Smooth with pustules or weakly
cancellate, especially on earlier chambers; tendency to
defoliate.
Test morphology: Highly trochospiral, globular,
spherical morphology with 4 1/2 to 6 chambers in the final
whorl and up to 3 1/2 whorls in the test; chambers
moderately inflated, radially compressed but elongate
in a dorso-ventral direction, increasing slowly in size,
with final one or two chambers commonly flattened,
reduced in size and added high in the spiral and arching
over umbilicus; dorsal sutures slightly curved, depressed.
Aperture a broad arch overhanging umbilicus, with
narrow imperforate lip; umbilicus varying from narrow
in specimens with 4 1/2 chambers in the final whorl to
broad and deep in specimens with more; ventral sutures
slightly curved, depressed; weak tendency for sinistral
coiling.
Size: Holotype length 0.51 mm, breadth 0.42
mm, height 0.46 mm. |
Discussion / Comments: |
Pearson et al. (2006):
DISTINGUISHING FEATURES.-
Turborotalia
altispiroides is distinguished from T pomeroli by its -
higher spire, more dorso-ventrally extended chambers,
and usually by having more chambers in the final whorl
and a more umbilically-centered aperture.
DISCUSSION.-
This taxon has rarely been identified,
despite being a distinctive and stratigraphically useful
form. We illustrate the holotype in SEM for the first time
(Pl. 15.1, Figs. 1-3). It is a large, high-spired species
that, as originally noted by Bermudez (1961), is
reminiscent in general shape of Neogene
Dentoglobigerina altispira( Cushman and Jarvis)
although it lacks the distinct umbilical teeth of that taxon.
We have observed extreme variants in ODP Site 865
(equatorial mid Pacific Ocean - see P1. 15.1, Fig. 11).
Morphometric studies (P.N. Pearson, unpublished data)
show that it is a separate species from T. pomeroli,
although the two intergrade in the lower part of the range
of altispiroides. Its extinction in Zone E14 may prove
to be a useful marker horizon, although it needs further
documentation.
PHYLOGENETIC RELATIONSHIPS.-
Evolved from
Turborotalia pomeroli and became extinct in the middle
Eocene.
STRATIGRAPHIC RANGE.-
Middle Eocene, upper
Zone Ell to lower Zone E14.
GEOGRAPHIC DISTRIBUTION.- Probably cosmopolitan.
STABLE ISOTOPE PALEOBIOLOGY.-
Oxygen and
carbon isotopic values are similar to T. pomeroli and
intermediate in comparison to other species (P.N.
Pearson, unpublished data). |
Systematics: |
35 Ordo Foraminiferida
Superfamilia Globigerinaceae
Familia Hedbergellidae
Genus Turborotalia
Species Turborotalia altispiroides
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Synonym list: |
Pearson et al. (2006):
1953 Globorotalia centralis Cushman & Bermudez. - Beckmann : p.396 pl. 26; fig. 8-9 [middle-upper
Eocene, Oceanic Fm., Barbados]
p 1957 Globorotalia centralis Cushman & Bermudez. - Bolli : p.169 pl. 39; fig. 2a-b [middle Eocene
Porticulasphaera mexicana Zone. Navet Fm.,
Trinidad];
[Not Cushman and Bermudez, 1937]
2006 Turborotalia altispiroides Bermudez. - Pearson et al. : p.439 pl. 15.1; fig. 1-15 (Pl. 15.l, Figs. 1-3; new SEMs of holotype of
Turborotalia altispiroides Bermudez)
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Specimen: |
Smithsonian Museum of Natural History, Washington, D.C., Inventory number: USNM 639071
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References: |
Beckmann,J.P. (1953): Die Foraminiferen der Oceanic Formation (Eocaen-Oligocaen) von Barbados. KI. Antillen . Eclogae Geologicae Helvetiae Vol. 46 p. 301-412
Bolli,H.M. (1957): Planktonic Foraminifera from the Eocene Navet and San Fernando formations of Trinidad, B.W.I. . Bull. U.S. natl. Mus. Vol. 215 p. 155-172
Bermudez,P.J. (1961): Contribucion al estudio de las Globigerinidea de la region Caribe-Antillana (Paleocene-Reciente). In: Boletino Geologia (Venezuela), Special Publicacion Vol. 3
Pearson,P.N.; Olsson,R.K.; Hemleben,C.; Huber,B.T. and Berggren,W.A. (2006): Atlas of Eocene Planktonic Foraminifera. p. 1-513
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