"Globorotalia miotumida (Jenkins 1960) may represent a thin-walled form of Gr. (G.) conoidea Walters. If so, it should have priority." [Kennett & Srinivasan 1983]
"G. explicationis Jenkins 1967 is closely related to G. miotumida but is distinguished from it in possessing a final chamber which appears to be uncoiling as seen in the side view of the holotype. G. explicationis evolved from G. miotumida in the Middle Miocene and ranges into the Late Miocene (Jenkins, 1971). In New Zealand it is fairly rare but at DSDP Leg 29 Site 284 it is quite common, and specimens referred to G. explicationis were found at DSDP Leg 40 Sites 360 and 362 (Jenkins, 1975, 1978c)." [Jenkins 1985] NB Lam & Leckie (2020) regard this as a distinct species.
"Globorotalia iwaiensis Takayanagi and Oda clearly differs from Globorotalia conoidea Walters by its thinner wall." [Hayashi et al. 2003]
Taxonomic discussion: Kennett & Srinivasan (1983) used the name G. conoidea but noted that: "Globorotalia miotumida (Jenkins 1960) may represent a thin-walled form of Gr. (G.) conoidea Walters. If so, it should have priority." Cifelli and Scott (1986), Scott et al. (1990) and Lam & Leckie (2020) all conclude that they were indeed synonyms, and so used the name miotumida.
Distinguishing features: Parent taxon (Globoconella): Globorotaliids having a high-arched aperture This taxon: Like G. miozea but much larger size, with more conical umbilical side, and tendency to develop a distinct keel
NB These concise distinguishing features statements are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus. They are being edited as the site is developed and comments on them are especially welcome.
Description
Morphology: Test relatively large, a relatively low trochospire consisting of 2½ to 3 whorls of slowly enlarging chambers, 4½ to 5 chambers in the final whorl; spiral side slightly convex, umbilical side highly conical; periphery bluntly rounded and thickened on early chambers, but on later chambers more sharply angled, with a narrow, cord like keel; sutures on spiral side strongly recurved, slightly raised, on umbilical side depressed, radial to slightly curved: Surface finely perforate, but earlier chambers show a progressive secondary thick- ening, especially on the periphery and on the umbilical surface. Umbilicus small, open; aperture interiomarginal, umbilical-extraumbilical, a low, distinct arch bordered by an indistinct rim. [Kennett & Srinivasan 1983] Wall type: Non-spinose; Cancellate [Aze 2011]
Character matrix
test outline:
Subcircular
chamber arrangement:
Trochospiral
edge view:
Planoconvex
aperture:
Umbilical-extraumbilical
sp chamber shape:
Crescentic
coiling axis:
Low
periphery:
Single keel
aperture border:
Thin lip
umb chbr shape:
Subtriangular
umbilicus:
Narrow
periph margin shape:
Subangular
accessory apertures:
None
spiral sutures:
Flush
umb depth:
Shallow
wall texture:
Smooth
shell porosity:
Macroperforate: >2.5µm
umbilical or test sutures:
Weakly depressed
final-whorl chambers:
4.5-5
N.B. These characters are used for advanced search. N/A - not applicable
Biogeography and Palaeobiology
Geographic distributionTemperate to warm subtropical. [Kennett & Srinivasan 1983] Low to middle latitudes [Aze et al. 2011, based on Kennett & Srinivasan (1983)]
[SCOR WG138]
Isotope paleobiologyAze et al. 2011 ecogroup 3 - Open ocean thermocline. Based on light δ13C and relatively heavy δ18O. Sources cited by Aze et al. 2011 (appendix S3): Schneider & Kennett (1996) Phylogenetic relationsGr. (G.) conoidea differs from Gr. (G.) miozea by its much larger size, by its much more conical umbilical side, and by its tendency to develop a distinct keel. [Kennett & Srinivasan 1983]
Geological Range: Last occurrence (top): within M13b subzone (6.14-8.58Ma, top in Messinian stage). Data source: Wei 1994 (age from fig.1 converted to modern zone) First occurrence (base): within N9 zone (14.24-15.10Ma, base in Langhian stage). Data source: Kennett & Srinivasan 1983
Plot of occurrence data:
Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
Histogram - Neptune occurrence data from DSDP and ODP proceedings. Pale shading <50 samples in time bin. Interpret with caution & read these notes
Primary source for this page: Kennett & Srinivasan 1983, p.112
References:
Aze, T. et al. (2011). A phylogeny of Cenozoic macroperforate planktonic foraminifera from fossil data. Biological Reviews. 86: 900-927. gs
Cifelli, R. & Scott, G. H. (1986). Stratigraphic record of the Neogene globorotaliid radiation (Planktonic Foraminiferida). Smithsonian Contributions to Paleobiology. 58: 101-. gs
Hayashi, H., Kurihara, Y., Horiuchi, S., Iwashita, T. & Yanagisawa, Y. (2003). Planktonic foraminifera biostratigraphy of the Miocene sequence in the Iwadono Hills, Central Japan: An Integrated approach. Palaios. 18: 176-191. gs
Kennett, J. P. & Srinivasan, M. S. (1983). Neogene Planktonic Foraminifera. Hutchinson Ross Publishing Co., Stroudsburg, Pennsylvania. 1-265. gs
Lam, A. & Leckie, R. M. (2020a). Late Neogene and Quaternary diversity and taxonomy of subtropical to temperate planktic foraminifera across the Kuroshio Current Extension, northwest Pacific Ocean. Micropaleontology. 66(3): 177-268. gs
Schneider, C. E. & Kennett, J. P. (1996). Isotopic evidence for interspecies habitat differences during evolution of the Neogene planktonic foraminiferal clade Globoconella. Paleobiology. 22: 282-303. gs
Scott, G. H., Bishop, S. & Burt, B. J. (1990). Guide to some Neogene Globorotalids (Foraminiferida) from New Zealand. New Zealand Geological Survey, Paleontological Bulletin. 61: 1-135. gs
Walters, R. (1965). The Globorotalia zealandica and G. miozea lineages. New Zealand Journal of Geology and Geophysics. 8: 109-127. gs
Wei, K. -Y. (1994b). Stratophenetic tracing of phylogeny using SIMCA pattern recognition technique: a case study of the late Neogene planktic foraminifera Globoconella clade. Paleobiology. 20(1): 52-65. gs
Globoconella miotumida compiled by the pforams@mikrotax project teamviewed: 14-12-2024
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