Hantkenina dumblei Weinzierl & Applin 1929 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.
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Species Hantkenina dumblei Weinzierl & Applin 1929 |
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| Alternative name: |
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| Diagnosis / Definition: |
Pearson et al. (2006):
DESCRIPTION.
Type of wall: Smooth, normal perforate and
probably nonspinose; tubulospine surface smooth or
with fine spiral striations, imperforate or perforated by
small sparsely distributed pores.
Test morphology: Planispiral, involute,
biumbilicate and laterally compressed; 5-7 chambers in
the final whorl, expanding and lengthening rapidly as
added; chambers subtriangular, closely appressed and
in contact with each other along their entire radial length;
each chamber of the final whorl extends into a hollow
tubulospine; aperture is an elongated equatorial arch,
extending about halfway up the apertural face, widening
towards the base into weak basal lobes, bordered by an
imperforate flaring lip; sutures depressed, straight,
becoming sigmoidal with small 'web-like' remnants of
relict apertures sometimes present within them;
tubulospines short and stout on early chambers,
becoming long and slender in later stages, sometimes
extremely long, arising sharply from the supporting
chamber wall, inclined forward slightly in the direction
of coiling (-457, positioned close to or at the anterior
chamber suture; anterior chamber shoulder is
nonexistent giving weak incisions between chambers,
distal ends taper into fine points, unornamented or with
very small finger-like projections (coronet structure of Ramsay, 1962), a small terminal aperture opening from
the axial canal can sometimes be observed in the adult
chanlbers of well preserved specimens.
Size: Maximum diameter (excluding tubulospines)
0.40-90 mm.
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| Discussion / Comments: |
Toumarkine & Luterbacher (1985):
Hantkenina dumblei has a more compact and more compressed test than H. nuttalli and H. mexicana. The chambers encroach 5 on each other and tend to fuse. The periphery is less lobate than in H. liebusi but more so than in H. alabamensis.
Pearson et al. (2006):
DISTINGUISHING FEATURES.-
Hantkenina
dumblei is distinguished from H. liebusi by the larger
size, more continuous peripheral outline, greater number
of chambers in the adult whorl and by the anterior, near
sutural position of the tubulospines. It is differentiated
from H. lehneri by the more continuous periphery and
broad-based, triangular shape of the final whorl
chambers. It is distinguished from H. compressa and
H. alabamensis by two principal features. Firstly, the
peripheral outline is more rapidly expanding along the radial axis, and second, chambers are usually free of
contact with the tubulospine of the previous chamber,
whereas in the latter species the tubulospines contact
and overlap with the posterior wall of the adjacent
younger chamber. In addition, tubulospines in H.
dumblei are inclined at a relatively low angle, whereas
in H. alabamensis they are strongly inclined with respect
to the test periphery. It differs from H. australis in the
larger size and having straight tubulospines.
DISCUSSION.-
Blow (1979), like Brönnimann
(1 950), recognized an evolutionary relationship between
H. dumblei and the lower middle Eocene hantkeninids,
e.g., H. mexicana, but considered it to be unrelated to
later species, e.g., H. alabamensis. According to Blow,
the early middle and late middle Eocene groups evolved
independently from separate Pseudohastigerina
ancestors. Morphometric analysis (Coxall, 2000) and
stratigraphic evidence from deep-sea cores demonstrate
that the H. alabamensis morphology evolved gradually
from H. dumblei via the intermediate H. compressa and,
thus, as argued by Pearson and others (1993), the
hantkeninids are a monophyletic group. In contrast to
Blow (1979) therefore, we regard H. dumblei as an
intermediate morphospecies within a single continuous evolving lineage, not as the end member of an early
hantkeninid radiation.
PHYLOGENETIC RELATIONSHIPS.-
Hantkenina
dumblei evolved from H. liebusi by an increase in the
rate of chamber expansion, closer appression of the
chambers and forward migration of the tubulospines. It
is closely related to H. compressa, which is intermediate
between this form and H. alabamensis.
STRATIGRAPHIC RANGE.-
Middle Eocene, mid Zone E9 to mid E13.
GEOGRAPHIC DISTRIBUTION.-
This species has
a global distribution in mid-low latitudes. It occurs in
abundance at ODP Site 865 in Zones E10-E11 in
association with Hantkenina lehneri and Morozovelloides
lehneri. It has also been found at relatively
high northerly latitudes compared to other hantkeninid
species, e.g. ODP Site 647 (North Atlantic) in
association with H. australis.
STABLE ISOTOPE PALEOBIOL0GY.-
Hantkenina
dumblei has higher ō18O and lower ō13C than
Morozovelloides and a similar isotopic signature to
Turborotalia frontosa (Pearson and others, 1993,2001;
Coxall and others, 2000), suggesting a deep to
intermediate depth habitat. This is supported by the
boron isotope data of Pearson and Palmer (1 999). There
is no ō13C enrichment trend with increasing test size. |
| Systematics: |
15
Classis Foraminifera
Genus Hantkenina
Species Hantkenina alabamensis
35
Ordo Foraminiferida
Superfamilia Globigerinaceae
Familia Hantkeninidae
Genus Hantkenina
Species Hantkenina dumblei
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| Synonym list: |
Toumarkine & Luterbacher (1985):
1929 Hantkenina dumblei Weinzierl & Applin. - Weinzierl & Applin : p.402 pl 43 figs 5a-b (type reference)
1950 Hantkenina dumblei Weinzierl & Applin. - Brönnimann : p.409 (lectotype= specimen figured by Weinzierl & Applin, 1929, pl 43 fig. 5b))
1985 Hantkenina dumblei Weinzierl & Applin. - Toumarkine & Luterbacher : p.123 figs 24,1-5
1929 Hantkenina dumblei Weinzierl & Applin. - Weinzierl & Applin : p.402 pl. 43; fig. 5a-b, lectotype = fig. 5b (designated by Brönnimann, 1950) [middle Eocene, Subsurface Yegua Fm. of the Texas
Gulf Coast]
1939 Hantkenina cf. dumblei Weinzierl & Applin. - Cushman & Siegfus : p.32 pl. 7; fig. 2 [middle Eocene,
Kreyenhagen shale, California]
1968 Hantkenina dumblei Weinzierl & Applin. - Raju : p.290 pl. 1; fig. 5 [middle Eocene
Truncorotaloides topilensis Zone, Karaikal, India].
1979 Hantkenina (Aragonella) dumblei Weinzierl & Applin. - Blow : p.1169 pl. 182; fig. 5-10 [middle Eocene Zone
P l l, DSDP Sample 2 1A-1-4, 148- 150 cm, South Atlantic
Ocean]
1992 Hantkenina dumblei Weinzierl & Applin. - Rajshekar : p.500 pl. 1; fig. 4 [middle Eocene,
Andaman Island, Indian Ocean]
2006 Hantkenina dumblei Weinzierl & Applin. - Pearson et al. : p.239 pl. 8.7; fig. 1-19 (Pl. 8.7, Figs. 1-2: new SEMs of the lectotype of
Hantkenina dumblei Weinzerl and Applin)
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| Was used in synonym list of: |
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| Specimen: |
Cushman Collection - Smithsonian Museum of Natural History, Washington, D.C., Inventory number: USNM 12204
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| References: |
Weinzierl,L.L. and Applin,E.R. (1929):
The Claiborne Formation on the Coastal Domes . Journal of Paleontology Vol. 3(4) p. 384-410
Cushman,J.A. and Siegfus,S.S.. (1939):
Some new and interesting foraminifera from the Kreyenhagen shale of California . Contributions from the Cushman Laboratory for Foraminiferal Research Vol. 15 p. 32
Thalmann,H.E. (1942):
Foraminiferal genus Hantkenina and its subgenera . American Journal of Sciences Vol. 240 p. 809-823
Brönnimann,P. (1950):
The Genus Hantkenina Cushman in Trinidad and Barbados, B.W.I. . Journal of Paleontology Vol. 24 p. 397-420
Raju,D.S.N. (1968):
Eocene-Oligocene planktonic foraminiferal biostratigraphy of Cauvery basin, South India . Memoires of the Geological Society of India Vol. 2 p. 286-289
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
Rajshekar,C.. (1992):
The Genus Hantkenina from Baratang Island, Andaman, India . Journal of Geology Society of India Vol. 39 p. 495-501
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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