pforams@mikrotax - Globoconella terminalis pforams@mikrotax - Globoconella terminalis

Globoconella terminalis


Classification: pf_cenozoic -> Globorotaliidae -> Globoconella -> Globoconella terminalis
Sister taxa: G. triangula, G. inflata, G. puncticulata, G. terminalis, G. pliozea, G. conomiozea, G. miotumida, G. miozea, G. panda, G. sp.

Taxonomy

Citation: Globoconella terminalis (Wei 1987)
taxonomic rank: species
Basionym: Globorotalia conomiozea terminalis Wei 1987
Synonyms:
Taxonomic discussion: Wei (1987) noted that "Globorotalia conomiozea mons Hornibrook, 1981 morphologically resembles this subspecies [terminalis]. However, the reported stratigraphic range of G. conomiozea mons is in the Lower Pliocene (Hornibrook, 1981) which is higher than that of G. conomiozea terminalis (Fig. 12). The phylogenetic and taxonomic relationship between these two subspecies needs further examination."

The argument of Wei (1987) for separating the (sub)species mons and terminalis based on stratigraphic range seems to be undermined by the data of Wei (1994) which extends the range of terminalis into the basal Pliocene. So, possibly mons is a senior synonym of terminalis. However, we follow the conventional taxonomy here pending critical re-evaluation by the Neogene Planktonic foraminifera working group [editor's comment - JRY 2019]

Catalog entries: Globorotalia (Globoconella) conomiozea terminalis, Globorotalia conomiozea mons

Type images:

Distinguishing features:
Parent taxon (Globoconella): Globorotaliids having a high-arched aperture
This taxon: Very high conical angle (64-70°), margin acute with distinctive to faint 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 low trochospiral, planoconvex, coiling dominantly sinistral; umbilical side strongly vaulted to form a prominent peak, high conical angle (64-70°). Periphery subovate, margin acute with distinctive to faint keel, four to four and one-half chambers in the final whorl. Aperture elongate, bordered by a lip, interiomarginal, extraumbilical; tightly coiled test causes umbilicus reduced or absent. Sutures on spiral side strongly curved, on umbilical side depressed, radial to slightly curved. Surface finely perforate, but early chambers covered with dense pustules, last chamber smooth. [Wei 1987]

Wall type:
Non-spinose; Cancellate [Aze 2011]

Character matrix
test outline:Subquadratechamber arrangement:Trochospiraledge view:Planoconvexaperture:Umbilical-extraumbilical
sp chamber shape:Crescenticcoiling axis:Lowperiphery:Single keelaperture border:Thin lip
umb chbr shape:Subtriangularumbilicus:Narrowperiph margin shape:Subangularaccessory apertures:None
spiral sutures:Flushumb depth:Shallowwall texture:Smoothshell porosity:Macroperforate: >2.5µm
umbilical or test sutures:Weakly depressedfinal-whorl chambers:4-4.5 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution

0 [Aze et al. 2011, based on Wei (1987)]

[SCOR WG138]


Isotope paleobiology
Aze 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 relations
It has been recognized that the increase of conicalness is one of the most distinctive evolutionary trends of Globoconella in the late Miocene (Kennett, 1966); G. conomiozea terminalis represents the extremity of this trend, culminating in an architectural threshold, leading to the loss of keel, and tending toward peripheral rounding as an inevitable consequence of continuously increasing "conicalness" [Wei 1987]

Most likely ancestor: Globoconella conomiozea - at confidence level 3 (out of 5). Data source: Wei 1994, fig. 1.
Likely descendants: Globoconella pliozea; Globoconella puncticulata; Globoconella sphericomiozea; plot with descendants

Biostratigraphic distribution

Geological Range:
Last occurrence (top): within PL1 [Atl.] zone (4.37-5.72Ma, top in Zanclean stage). Data source: Wei 1994 (quoted age converted to modern zone)
First occurrence (base): within M14 [Atl.] zone (5.72-6.14Ma, base in Messinian stage). Data source: Wei 1994 (quoted age converted to modern zone)

Plot of occurrence data:

References:

Aze, T. et al. (2011). A phylogeny of Cenozoic macroperforate planktonic foraminifera from fossil data. Biological Reviews. 86: 900-927. gs

Hornibrook, N. d. B. (1981). Globorotalia in the late Pliocene and early Pleistocene of New Zealand. New Zealand Journal of Geology and Geophysics. 24: 263-292. gs

Kennett, J. P. (1966). The Globorotalia crassaformis bioseries in north Westland and Marlborough, New Zealand,. Micropaleontology. 12: 235-245. 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

Wei, K. -Y. (1987). Multivariate morphometric differentiation of chronospecies in the late Neogene planktonic foraminiferal lineage Globoconella. Marine Micropaleontology. 12: 183-202. gs

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Globoconella terminalis compiled by the pforams@mikrotax project team viewed: 10-12-2024

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Comments (2)

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Hello

Globorotalia conomiozea subsp. mons Hornibrook, 1982 is included in the synonyms and has priority over wei (1987)

Best,

François

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Good point - Wei (1987) argues they have different ranges but he seems to have undermined this argument by extending the range of terminalis in his later papers. terminalis is the name people apply to this form and I am only supposed to be documenting usage here. There is a working group to clear up the multiple problems with Neogene p foram taxonomy but I will flag this up more clearly as an issue.

Jeremy