Morozovelloides coronatus 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 | . |
Notice: This catalogue page may contain unedited data.
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Species Morozovelloides coronatus Blow 1979 |
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| Diagnosis / Definition: |
Pearson et al. (2006):
DESCRIPTION.
Type of wall: Muricate, normal perforate, with
concentration of muricae around periphery and on
umbilical shoulders of chambers.
Test morphology: Low trochospiral, elongateoval
to subcircular, moderately lobulate peripheral
outline; 5-5 1/2 chambers in relatively evolute coil,
subtriangular, weakly inflated, increasing gradually in
size; umbilical sutures radial, straight to weakly reflexed
at junction with peripheral margin; umbilicus relatively
wide, deep and rimmed by distinct circuinumbilical
"coronet" of densely clustered/fused muricae on
circumumbilical chamber tips; primary aperture a low
arch extending nearly to the periphery and rimmed by a
thickened margin; about 11 - 12 chambers in 2 1/2-3 whorls
(muricate overgrowth on early chambers renders
differentiation difficult); chambers vary from lensshaped
to trapezoidal (early chambers of last whorl) to
subtriangular or subquadrate as a function of disposition of intercameral sutures; flat to slightly concave near
peripheral margins; intercameral sutures muricate and
limbate, curved, tangential to the periphery in early part
of last whorl, radial, straight in terminal part of last whorl,
recurved near junction with peripheral, muricocarina;
in edge view low, asymmetrically biconvex; umbilicoconvex,
early whorl(s) of spiral side slightly elevated;
distinct and relatively thick marginal muricocarina
Size: Maximum diameter: 0.43 mm (Blow, 1979,
p. 1016). |
| Discussion / Comments: |
Pearson et al. (2006):
DISTINGUISHING FEATURES.-
This taxon is
distinguished from the closely related M. crassatus by
the distinct circuinumbilical clustering of muricae on
the circumumbilical tips of the chambers resulting in
the development of a 'coronet' - like ornament. The
muricocarina is usually more completely fused than in
other species of Morozovelloides.
DISCUSSION.-
Originally described as coronata, the
ending has been changed to agree in gender with the
genus Morozovelloides(I CZN, Art. 3 1.2). Blow (1 969,
p. 370) differentiated this form based on the
circumumbilical muricate 'coronet' and indicated it
would be described in a forthcoming paper by himself
and one of us (WAB). Tn fact, it was described
posthumously by Blow (1979:1016) but not before the
name had appeared 5 years earlier in a citation by
Fleisher (1974) to what was at the time Blow's
manuscript. Article 13(a) of the ICZN Code of
Zoological Nomenclature requires every scientific name
published after 1930, in order to be available, to be
"(1 3.1.1) accompanied by a description or definition that
states in words characters that are purported to
differentiate the taxon, or (13.1.2) accompanied by a
bibliographic reference to such a published statement ...,
or (13.1.3) proposed expressly as a new replacement
name ...." Fleisher (1974) published an illustration, but
included no description of the species; hence (i) is not satisfied (it has to be in words; an illustration is not
sufficient), and although he published a citation to Blow,
it was to a work not published, and hence (ii) is not
satisfied. Fleisher's use of coronata was, therefore, a
nornen nudum and hence not available (see above
synonymy; information on status of coronatus provided
by R. Fleisher, pers. comm., 1998); the species is
correctly attributed to Blow (1979).
While the gencral morphology of cvassatus and
coronatus is similar in many respects and the
stratigraphic range is comparable, we retain coronatus
for those forms distinguished by the muricate coronet, a
wider umbilicus and generally more pronouncedly muricate carina. To investigate the range of variability
of coronatus, we have illustrated several new specimens
from the type locality in Kilwa, Tanzania (PI. 10.2, Figs.
4-7, 15-16). We note that coronatus displays a greater
range in the degree of umbilical vaulting (and hence the
peripheral angle as seen in edge view) than crassatus.
The typical morphology, as shown by the holotype, is a
relatively dorso-ventrally compressed form, but other,
more highly vaulted variants occur that are reminiscent
of lower Eocene Morozovella,formosa. Some specimens
show a transitional morphology to Morozovelloides
lehneri (PI. 10.2, Fig. 12).
PHYLOGENETIC RELATIONSHIPS.-
This species
evolved from M. crassatus and was ancestral to M.
lehneri.
STRATIGRAPHIC RANGE.-
Zone E8-E12 (middle
Eocene; Blow, 1979). A
GEOGRAPHIC DISTRIBUTION.-
Apparently
characteristic of (sub)tropical Tethyan areas of the world
(Caribbean, Indo-Pacific). Citations of its occurrence are
too rare to give an accurate picture of its global
geographic distribution.
STABLE ISOTOPE PALEOBIOL0GY.-
Oxygen and
carbon isotopes are similar to other Morozovelloides and
indicate a shallow water, symbiotic habitat (Wade and
others, 2001, Wade and Kroon, 2002; recorded as
Morozovella spinulosa). |
| Systematics: |
35
Ordo Foraminiferida
Superfamilia Globigerinaceae
Familia Truncorotaloididae
Genus Morozovelloides
Species Morozovelloides coronatus
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| Synonym list: |
Pearson et al. (2006):
1957 Globorotalia spinulosa Cushman. - Bolli : p.168 pl. 38; fig. 6a-7c [middle Eocene Hantkenina aragonensis Zone,
Navet Fm., Trinidad]
p 1957 Globorotalia lehneri Cushman & Jarvis. - Bolli : p.169 pl. 38; fig. 9a-c, 13 [middle Eocene
Porticulasphaera hbckmanni Zone, Navet Fm., Trinidad];
[Not Cushman and Jarvis, 1929]
1962 Globorotalia spinulosa Cushman. - Saito : p.215 pl. 33; fig. 9a-c [middle Eocene, Ha-Ha-Jima, Bonin Islands, Western
Pacific Ocean]; [Not Cushman, 1927]
1969 Globorotalia (Globorotalia) spinulosa Cushman. - Blow : p.370 pl. 50, fig. 2 [Zone P13, Kilwa area, Tanzania]; 4,5 [Zone P11 (not Zone P10 as stated; see
Blow, 1979: 101 7), Kilwa area, Tanzania] [Not Cushman,
1927]
1979 Globorotalia (Morozovella) coronata Blow. - Blow : p.1016 pl. 50, fig. 2-5 (refigured from Blow, 1969, pl. 50);
pl. 168, fig. 1-8 (8=holotype);
pl. 229, fig. 5,6;
pl. 230, fig. 1-6 [Zone P 1 1, Kilwa area, Tanzania]
2004 Morozovella coronata Blow. - Pearson et al. : p.37 pl. 2; fig. 10, 11 [middle Eocene, Zone P 1 1, Tanzania Drilling
Project Site 2, Kilwa Masoka, Tanzania]
2006 Morozovelloides coronatus Blow. - Pearson et al. : p.335 pl. 10.2; fig. 1-16 (Pl. 10.2, Fig. l : holotype of Globorotalia
(Morozovella) coronata Blow, re-illustrated)
(Pl. 10.2, Figs. 2-3: paratypes of Globorotalia
(Morozovella) coronata Blow, re-illustrated)
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| Specimen: |
Natural History Museum, London, Inventory number: BP 63/9
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| References: |
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
Saito,T. (1962):
Eocene planktonic foraminifera from Hahajima (Hillsborough Island) . Trans. Proc. Paleontol. Soc. Japan, news series Vol. 45 p. 209-225
Blow,W.H. (1969):
Late middle Eocene to Recent planktonic foraminiferal biostratigraphy.
In: Proceedings of the First International Conference on Planktonic Microfossils, Geneva 1967 Vol. 1 Eds: Bronnimann, P.Renz, H.H. p. 199-422
Blow,W.H. (1979):
The Cainozoic Globigerinida. 3 Vols p. 1413 pp
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
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