Tenuitella patefacta Li 1987 from: Pearson, P.N.Olsson, R.K.Hemleben, C.Huber, B.T.Berggren, W.A. (2006): Atlas of Eocene Planktonic Foraminifera. p. 1-513 | . |
Notice: This catalogue page may contain unedited data.
|
Species Tenuitella patefacta Li 1987 |
|
|
|
| Diagnosis / Definition: |
Pearson et al. (2006):
DESCRIPTION.
Type of wall: Microperforate, surface smooth to
finely pustulose, pustules irregularly scattered on
umbilical and spiral sides of test.
Test morphology: Test small, lobate circular in
equatorial outline, equatorial periphery rounded;
chambers globular, coiled in a very low trochospire,
increasing gradually in size, 5-6 in the final whorl, nearly
symmetrical in edge view; sutures depressed, curved on
the spiral side, radial on umbilical side; umbilicus small;
aperture a low extraumbilical-umbilical arch bordered
by a narrow, equidimensional lip.
Size: Holotype maximum diameter: 0.16 mm. |
| Discussion / Comments: |
Pearson et al. (2006):
DISTINGUISHING FEATURES.-
Differs from
Tenuitella insolita by having a low rather than highly
arched, extraumbilical aperture; differs from T. gemma
by having a more lobate equatorial outline and a more
oval equatorial outline, a more open umbilicus and an
aperture that extends closer to the peripheral margin;
differs from T. praegemma by lacking secondary
apertures or apertural lips and having globular rather
than oval or subcrescentic chambers.
DISCUSSION.-
Comparison of the test outline,
umbilical morphology, and height of the aperture in the
T. patefacta holotype (re-illustrated on Pl. 16.7, Figs. 1-
2) with those features on the holotype of T. gemma (Pl.
16.7, Figs. 16-1 8) and illustrations of T. insolita (Pl. 16.5)
reveals why Li (1987) considered patefacta to be the
intermediate link between insolita and gemma.
Specimens designated as Praetenuitella patefacta by
Poag and Commeau (1995) (re-illustrated on Pl. 16.7,
Figs. 3-5) have a more circular aperture and a more
closed umbilicus than Li's primary type specimens but
still fall within Li's species concept. An early Oligocene
specimen designated by Huber (1 991) as T. gemma (reillustrated
on Pl. 16.7: Figs. 9-10) is too deeply
umbilicate for that species and is reassigned to T.
patefacta despite having a narrower and deeper
umbilicus than found in Li's (1 987) type specimen. This
latter specimen is nearly identical to a specimen assigned
to T. patefacta from the upper Eocene specimen from
the New Jersey Coastal Plain (Pl. 16.7, Figs. 6-8). A
specimen previously assigned to T. praegemma forma
typica by Poag and Commeau (1995) (see Pl. 16.7, Figs.
13-14) is here considered to be T. patefacta because of
its more highly arched aperture, but the more pendulous
and axially broadening of the chambers and more closed
umbilicus are suggestive of T. praegemma. A specimen
designated as Globorotalia gemma by Poore and Bybell
(1988; re-illustrated on P1. 16.7, Figs. 11-12) is
reassigned to T. patefacta because of its relatively lobate
equatorial outline and more open umbilicus.
PHYLOGENETIC RELATIONSHIPS -
Descended
from T. insolita during the late Eocene; ancestral to T.
gemma, which first appeared during the latest Eocene.
STRATlGRAPHlC RANGE.-
Upper Eocene; Zone E15 to E16.
GEOGRAPHIC DISTRIBUTTON .-
Few records of
this species have been published. Identified in upper
Eocene sediments from the Atlantic coastal plain and
the southern Indian Ocean.
STABLE ISOTOPE PALEOBIOL0GY.-
No data
available.
REPOSITORY.-
Holotype and paratypes deposited in
the British Museum of Natural History, London. |
| Systematics: |
35
Ordo Foraminiferida
Superfamilia Globigerinaceae
Familia Cassigerinellidae
Genus Tenuitella
Species Tenuitella patefacta
|
| Synonym list: |
Pearson et al. (2006):
1987 Praetenuitella patefacta Li. - Li : p.309 pl. 1; fig. 6-10 [upper Eocene, Zone P16-P17, Choctaw County,
Alabama, USA]
1988 Globorotalia gemma Jenkins. - Poore & Bybell : p.16 pl. 3; fig. 1-6 [upper Eocene Turborotalia cunialensis Zone,
ACGS #4 borehole, Cape May, New Jersey Coastal
Plain]; [Not Jenkins, 1966]
1991 Tenuitella gemma Jenkins. - Huber : p.441 pl. 7; fig. 7-8 [lower Oligocene, ODP Site 744, Kerguelen
Plateau, southern Indian Ocean];
[Not Jenkins, 1966]
1995 Praetenuitella patefacta Li. - Poag & Commeau : pl. 9; fig. 18-20 [Upper Eocene, Zone P15, Exmore Core, Accomomack
County, Virginia]
1995 Praetenuitella patefacta Li. - Li et al. : p. 132-133 pl. 4; fig. 4-5 [upper Eocene, ODP Hole 749B, Kerguelen Plateau,
southern Indian Ocean]
1995 Praetenuitella insolita Jenkins. - Li et al. : pl. 4; fig. 6-8 [Upper Eocene, ODP Hole 749B, Kerguelen Palteau,
southern Indian Ocaean];
[Not Jenkins, 1966]
2006 Tenuitella patefacta Li. - Pearson et al. : p.497 pl. 16.7; fig. 1-14 (Pl. 16.7, Figs. 1, 2: SEMs of holotype of
Praetenuitella patefacta Li)
|
| References: |
Li,Q. (1987):
Origin, phylogenetic development and systematic taxonomy of the Tenuitella plexus (Globigerinitidae Globigerininina) . Journal of Foraminiferal Research Vol. 17 p. 298-320
Poore,R.Z. and Bybell,L.. (1988):
Eocene to Miocene biostratigraphy of New Jersey Core ACGS # 4: Implications for regional stratigraphy . U. S. Geological Survey Bulletin 1829 p. 1-22
Huber,B.T. (1991):
Paleogene and early Neogene planktonic foraminifer biostratigraphy of Sites 738 and 744, Kerguelen Plateau (southern Indian Ocean).
In: Proceedings of the Ocean Drilling Program, Scientific Results Vol. 119 Eds: Leckie, R.M.Sigurdsson, H.Acton, G.D.Draper, G. p. 427-449
Poag,C.W.. and Commeau,J.A.. (1995):
Paleocene to middle Miocene planktic foraminifera of the southwestern Salisbury Embayment, Virginia and Maryland: biostratigraphy, allostratigraphy, and sequence stratigraphy . Journal of Foraminiferal Research Vol. 25 p. 134-155
Li,Q.; McGowran,B. and Boersma,A. (1995):
Early Palaeocene Parvularuglobigerina and late Eocene Praetenuitella; does evolutionary convergence imply similar habitat? . Journal of Micropalaeontology Vol. 14 p. 119-134
Pearson,P.N.; Olsson,R.K.; Hemleben,C.; Huber,B.T. and Berggren,W.A. (2006):
Atlas of Eocene Planktonic Foraminifera. p. 1-513
|
This work is licensed under a Creative Commons Attribution 2.5 License.
|
|
Taxon Concept provided by