Acarinina rohri


Classification: pf_cenozoic -> Truncorotaloididae -> Acarinina -> Acarinina rohri
Sister taxa: << < A. interposita, A. echinata, A. pseudosubsphaerica, A. alticonica, A. soldadoensis, A. cuneicamerata, A. angulosa, A. africana, A. sibaiyaensis, A. esnehensis, A. mckannai, A. subsphaerica, A. bullbrooki, A. punctocarinata, A. boudreauxi, A. rohri, A. topilensis, A. praetopilensis, A. mcgowrani, A. quetra, A. pseudotopilensis, A. wilcoxensis, A. esnaensis, A. primitiva, A. coalingensis, A. nitida, A. strabocella, A. sp.,

Taxonomy

Citation: Acarinina rohri (Bronnimann & Bermudez 1953)
Rank: Species
Basionym: Truncorotaloides rohri
Synonyms:
Taxonomic discussion: The taxonomy of this morphotype is extremely complex and controversial. Several forms/taxa have been ascribed to, or differentiated from, this species over the past five decades. Below we attempt to reduce the complexity surrounding the rohri group to its most essential details:
1. Bronnimann and Bermúdez (1953) described rohri and differentiated three further varieties based on variation in chamber shape in the final perforate, nonspinose. whorl: guaracaraensis (rounded), mayoensis (angular) and piparoensis (subangular; intermediate between the rounded guaracaraensis and the central morphotype: rohri). In all, 21 well preserved specimens of guaracaraensis were recorded, 8 of rohri, 5 of piparoensis and only 2 of mayoensis; no discussion of stratigraphic extent of these morphotypes was presented.
2. Blow (1979, p. 951-953 and 1036-1041) differentiated the rohri complex into two distinct, but phylogenetically related groups: guaracaraensis and piparoensis were assigned to Acarinina (lacking distinct rimmed dorsal true supplementary apertures, degree of lateral angulation of chambers, degree of development of typical disjunct chambers and the organization of circumcameral/circumperipheral muriococarina typical of Truncorotaloides (as typified by rohri); while rohri and mayoensis (with the characters listed above) were placed in Truncorotaloides. The taxon guaracaraensis was placed in synonymy with Globigerinoides (vel Acarinina) pseudodubia Bandy (1949).
3. Blow (1979, p. 952-955) presented the case for derivation of rohri from Acarinina bullbrooki by way of the evolution / transition from A. pseudodubia to piparoensis: increased number of chambers in final whorl (4 to 5), gradual tendency to develop more laterally angulate and disjunct chamber geometry in last one or two chambers.
In our view a much more likely ancestor for
rohri is Acarinina topilensis, with which it shares several characters to the exclusion of A. bullbrooki, including the sinistal coiling bias, more incised sutures,
supplementary apertures and heavily muricate test. We have not differentiated from rohri the ‘transitional’ morphotypes illustrated by Blow of pseudodubia and piparoensis, preferring to illustrate the wide degree of variation we ascribe to rohri and its morphologic end- member mayoensis, which we include here in the synonymy of rohri.
The essentially neglected and rarely recognized taxon Globigerinoides pseudodubia Bandy may be a senior synonym of Acarinina rohri (for a dissenting view see Blow, 1979, p. 951 who considered it a senior synonym of G. (A.) guaracaraensis). We include this form provisionally as a questionable senior synonym of A. rohri.
The taxon Turborotalia (Acarinina) alteconica was described by Samuel (1972) as a high-spired variant of rohri. Similarly Truncorotaloides haynesi of Samanta seems to be a large, more openly coiled variant of rohri. [Berggren et al. 2006]

Catalog entries: Truncorotaloides rohri, Globigerinoides pseudodubia, Truncorotaloides haynesi, Truncorotaloides rohri guaracaraensis, Truncorotaloides rohri mayoensis, Truncorotaloides rohri piparoensis, Turborotalia (Acarinina) alteconica

Type images:

Distinguishing features: Like A. topilensis but more evolute, with 5-6 chambers in final whorl, final chamber more disjunct; strongly muricate especially on the umbilical shoulders, and around the peripheral margin.

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


Diagnostic characters: Acarinina rohri is distinguished by its strongly muricate test, particularly the concentration of muricae on the umbilical shoulders, and around the peripheral margin, the tendency to develop disjunct separation of chambers in stratigraphically younger forms and by the development of raised imperforate rims surrounding supplementary apertures on the later chambers on the spiral side. [Berggren et al. 2006]

Wall type: Densely muricate, normal perforate, nonspinose. [Berggren et al. 2006]

Test morphology: Low trochospiral test with about 12-13 chambers in an evolute spire, 5 (less commonly 6) rounded to subangular chambers in last whorl; final chamber usually wedge-shaped and with disjunct separation from antepenultimate chamber; sutures on umbilical side weakly curved, depressed; umbilicus narrow and relatively deep; aperture an umbilical-extraumbilical arch extending towards the peripheral margin; hemispherical to wedge-shaped chambers on spiral side separated by straight to weakly recurved, depressed sutures; distinct, rimmed supplementary apertures visible at the base of the antepenultimate and final chambers, rarely visible between earlier chambers in last whorl; subrounded to truncate in edge view; chambers on both sides of test strongly muricate. [Berggren et al. 2006]

Size: Maximum diameter of holotype 0.37 mm, thickness 0.22 mm. [Berggren et al. 2006]

Character matrix

test outline:Subcircularchamber arrangement:Trochospiraledge view:Planoconvexaperture:Umbilical-extraumbilical
sp chamber shape:Inflatedcoiling axis:Lowperiphery:N/Aaperture border:N/A
umb chbr shape:Inflatedumbilicus:Narrowperiph margin shape:Moderately roundedaccessory apertures:Sutural
spiral sutures:Moderately depressedumb depth:Deepwall texture:Coarsely muricateshell porosity:Finely Perforate: 1-2.5µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:5.0-6.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Widely distributed in (sub)tropical areas, Caribbean, Spain, Aquitaine, North Africa, Middle East, India. [Berggren et al. 2006]
Aze et al. 2011 summary: Low latitudes; based on Berggren et al. (2006b)

Isotope paleobiology: No data available. [Berggren et al. 2006]
Aze et al. 2011 ecogroup 1 - Open ocean mixed-layer tropical/subtropical, with symbionts. Based on very heavy δ13C and relatively light δ18O. Sources cited by Aze et al. 2011 (appendix S3): this study

Phylogenetic relations: Evolved from Acarinina topilensis via intermediate/transitional morphotypes ascribed to the pseudubia -piparoensis group (Blow, 1979, p. 951-955). [Berggren et al. 2006]

Most likely ancestor: Acarinina topilensis - at confidence level 4 (out of 5). Data source: Berggren et al. (2006) fig9.2.

Biostratigraphic distribution

Geological Range:
Notes: Zone E10 to Zone E13. [Berggren et al. 2006]
Last occurrence (top): within E13 zone (37.99-39.97Ma, top in Bartonian stage). Data source: Eocene Atlas
First occurrence (base): in mid part of E10 zone (50% up, 42.6Ma, in Lutetian stage). Data source: Eocene Atlas

Plot of occurrence data:

Primary source for this page: Berggren et al. 2006 - Eocene Atlas, chap. 9, p. 312

References:

Berggren, W. A., Pearson, P. N., Huber, B. T. & Wade, B. S. (2006). Taxonomy, biostratigraphy, and phylogeny of Eocene Acarinina. 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 9): 257-326. gs :: ::

Bermudez, P. J. (1961). Contribucion al estudio de las Globigerinidea de la region Caribe-Antillana (Paleoceno-Reciente). Editorial Sucre, Caracas. 1119-1393. gs :: ::

Blow, W. H. (1969). Late middle Eocene to Recent planktonic foraminiferal biostratigraphy. In, Bronnimann, P. & Renz, H. H. (eds) Proceedings of the First International Conference on Planktonic Microfossils, Geneva, 1967. E J Brill, Leiden 380-381. gs :: ::

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 :: ::

Brönnimann, P. & Bermudez, P. J. (1953). Truncorotaloides, a new foraminiferal genus from the Eocene of Trinidad, B.W.I. Journal of Paleontology. 27: 817-820. gs :: ::

Loeblich, A. R. & Tappan, H. (1957). Planktonic foraminifera of Paleocene and early Eocene Age from the Gulf and Atlantic coastal plains. In, Loeblich, A. R. , Jr. , Tappan, H. , Beckmann, J. P. , Bolli, H. M. , Montanaro Gallitelli, E. & Troelsen, J. C. (eds) Studies in Foraminifera. U.S. National Museum Bulletin. 215: 173-198. gs :: ::

Postuma, J. A. (1971). Manual of planktonic foraminifera. Elsevier for Shell Group, The Hague. 1-406. gs :: ::

Samuel, O. (1972). Planktonic Foraminifera from the Eocene in the Bakony mountains (Hungary). Zborník geologických vied, séria Západné Karpaty. 17: 165-206. gs :: ::


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Acarinina rohri compiled by the pforams@mikrotax project team viewed: 14-7-2020

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Comments (1)

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Bridget Wade

Hi Jeremy, the occurrence data of rohri is using both the Eocene Truncorotaloides rohri and the Oligocene Globigerina rohri (Bolli) - which is now synonymised into tripartita

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Jeremy Young (UK)

thanks Bridget - I probably need to do a thorough check of the Neptune synonymies. I have corrected this one now

Jeremy

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