All of the specimens of S. crociapertura except one (his pl. 176, fig. 5; here illustrated on Pl. 6.8, Fig. 8) from Tanzania illustrated by Blow, which includes the holotype, have a bulloides-type wall texture. However, the figure of S. crociapertura from the North Atlantic (his Pl. 160, fig. 2) as well as the one exception from Tanzania show a ruber/sacculifer-type wall texture. These specimens are similar to specimens from Tanzania on Plate 6.8, Figs. 9-14, which we have labeled S. cf. S. crociapertura because of the different wall texture. The holotype is from Zone E12 and the others are from Zones E8 and E9. It may be that the earlier morphotypes represent an early stage in the development of crociapertura, but we do not have sufficient stratigraphic control to show this.
Subbotina crociapertura is apparently little used by workers despite its distinctiveness. This may be in part due to a restricted biogeographic range. Blow’s record of the species is from low latitude localities in the southern hemisphere. We have recorded it from Tanzania and the Aragon Formation in Mexico, a
northern low latitude locality. Blow noted that the species was particularly common in the Indo-Pacific region. The origin of this species is most likely from S. roesnaesensis n. sp., which, although it has a ruber-type wall texture, has a more open umbilicus and an apertural lip which tapers in the posterior direction. The ruber-type wall texture appears closest to the bulloides-type and is regarded here as the most likely ancestor wall texture to the genus Globigerina which appears in the middle Eocene. Blow indicated that the range of S. crociapertura “virtually defines the Middle Eocene as a whole” (1979, p. 1259). Its origin appears to be in Zone E7. [Olsson et al. 2006]
Catalog entries: Subbotina crociapertura
Type images:Distinguishing features:
Parent taxon (Subbotina): Low trochospiral, tripartite test, with 3-4 rapidly inflating, globular chambers in final whorl.
Umbilicus nearly closed by tight coiling.
Wall cancellate with spines at nodes of the ridges, +/- spine collars.
This taxon: Chambers globular, slightly embracing. Aperture characteristically crooked, high-arched, and with prominent regular lip.
Morphology:
Wall type:
Size:
Character matrix
test outline: | Ovate | chamber arrangement: | Trochospiral | edge view: | Equally biconvex | aperture: | Umbilical |
sp chamber shape: | Globular | coiling axis: | Low | periphery: | N/A | aperture border: | Thick lip |
umb chbr shape: | Globular | umbilicus: | Narrow | periph margin shape: | Broadly rounded | accessory apertures: | None |
spiral sutures: | Moderately depressed | umb depth: | Deep | wall texture: | Spinose | shell porosity: | Finely Perforate: 1-2.5µm |
umbilical or test sutures: | Moderately depressed | final-whorl chambers: | 4-4 | N.B. These characters are used for advanced search. N/A - not applicable |
Geographic distribution
Aze et al. 2011 summary: Low latitudes; based on Olsson et al. (2006a)
Isotope paleobiology
Aze et al. 2011 ecogroup 4 - Open ocean sub-thermocline. Based on very light _13C and very heavy _18O. Sources cited by Aze et al. 2011 (appendix S3): Coxall et al. (2000); Pearson et al. (2001a)
Phylogenetic relations
Most likely ancestor: Subbotina yeguaensis - at confidence level 4 (out of 5). Data source: Olsson et al. 2006 f6.2.
Geological Range:
Notes: Zone E7 to Zone E12. [Olsson et al. 2006]
Last occurrence (top): within E12 zone (39.97-40.40Ma, top in Bartonian stage). Data source: Eocene Atlas
First occurrence (base): within E7 zone (45.72-50.20Ma, base in Ypresian stage). Data source: Eocene Atlas
Plot of occurrence data:
Primary source for this page: Olsson et al. 2006 - Eocene Atlas, chap. 6, p. 133
Blow, W. H. (1979). The Cainozoic Globigerinida: A study of the morphology, taxonomy, evolutionary relationships and stratigraphical distribution of some Globigerinida (mainly Globigerinacea). E. J. Brill, Leiden. 2: 1-1413. gs Olsson, R. K., Hemleben, C., Huber, B. T. & Berggren, W. A. (2006a). Taxonomy, biostratigraphy, and phylogeny of Eocene Globigerina, Globoturborotalita, Subbotina, and Turborotalita. In, Pearson, P. N., Olsson, R. K., Hemleben, C., Huber, B. T. & Berggren, W. A. (eds) Atlas of Eocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication . 41(Chap 6): 111-168. gs O Olsson, R. K., Pearson, P. N. & Huber, B. T. (2006c). Taxonomy, biostratigraphy, and phylogeny of Eocene Catapsydrax, Globorotaloides, Guembelitrioides, Paragloborotalia, Parasubbotina, and Pseudoglobigerinella n. gen. In, Pearson, P. N., Olsson, R. K., Hemleben, C., Huber, B. T. & Berggren, W. A. (eds) Atlas of Eocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication . 41(Chap 5): 67-110. gs O Pearson, P. N. et al. (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. 39: 25-62. gsReferences:
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Subbotina crociapertura compiled by the pforams@mikrotax project team viewed: 14-2-2025
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