Catapsydrax unicavus

Classification: pf_cenozoic -> spinose -> Globigerinidae -> Catapsydrax -> Catapsydrax unicavus
Sister taxa: C. dissimilis, C. globiformis, C. africanus, C. howei, C. unicavus, C. sp.,


Citation: Catapsydrax unicavus Bolli, Loeblich and Tappan 1957
Rank: Species
Basionym: Catapsydrax unicavus
Taxonomic discussion: The type specimen of unicavus (which is illustrated in SEM for the first time on Pl. 5.3, Figs. 1-3) is from the lower Miocene Cipero Formation of Trinidad. It is a compact form with a flat inner whorl. Bolli (1957b, p. 116) recorded the stratigraphic range of unicavus as beginning in the lower Oligocene Globigerina ampliapertura Zone. Bolli (1957b, p. 117) went on to describe the genus Globorotaloides for forms that traverse the supposedly characteristic morphologies of three genera in their ontogeny, namely a Globorotalia-like inner whorl, followed by a Globigerina-like stage where the aperture becomes umbilical, and finally a Catapsydrax-like stage with an umbilical bulla.
Comparisons of the respective holotypes of unicavus and suteri (Pl.5.3, Figs. 1-3, 9-11) reveal many similarities. Both are compact forms with a relatively flat inner whorl and a similar, cancellate wall texture, although neither is very well preserved. The two species differ mainly in the fact that suteri has a more inflated bulla. However we do not consider this an important characteristic, as it is very variable in populations, and conclude that the two specimens are conspecific, with suteri (Bolli) being a junior synonym of Catapsydrax unicavus. The status of specimens of true Globorotaloides that have been described as suteri in the literature are discussed under that genus, below.
Bronnimann (1952) described a small compact bullate species as Globigerina taroubaensis from the lower Eocene Navet Formation of Trinidad. The holotype is illustrated for the first time in SEM in Pl. 5.3, Figs. 5-7. It is very similar to the holotype of unicavus and we regard it as a possible senior synonym. However because taroubaensis has rarely been described by subsequent workers (with the notable exception of Blow, 1979, p. 1346) we recommend continuance of the unicavus name until such time as the respective taxa can be researched in more detail in their type sections. It may well be that taroubaensis will ultimately be recognized as specifically distinct, as argued by Blow (1979).
Finlay (1939) described (without illustrating) Globigerina linaperta var. turgida. Jenkins selected and illustrated a lectotype in 1964. Blow (1969) considered the taxon valid, placing it in Globigerinita which is a microperforate genus in contrast to the normal perforate turgida. Fleisher (1974) and Krasheninnikov and Basov (1983) assigned turgida to Globorotaloides following Jenkins (1964). In our opinion the taxon is best placed in Catapsydrax due to its bulla with a single aperture. We have chosen to regard turgida and unicavus as conspecific and since unicavus was first illustrated and is a well understood taxon we prefer to use this name for nomenclatural stability.
Specimens of Catapsydrax unicavus are consistently present in middle and upper Eocene planktonic foraminiferal assemblages, but only as a minor component. Stable isotope studies (e.g. Poore and Matthews, 1984) suggest that they occupied a deep-dwelling planktonic habitat, in which population sizes were never large. We have observed considerable variability in the degree of chamber appression and bulla morphology. However, we acknowledge that future studies may well reveal more than one valid taxon within our broad concept of unicavus, especially as regards the larger, more loosely coiled morphotypes; but with the present level of understanding we can suggest no consistent way to subdivide them. [Olsson et al. 2006]

Catalog entries: Catapsydrax unicavus;
Globigerina isahayensis;
Globigerina linaperta turgida;

Type images:

Short diagnosis: Distinguished from C. africanus by its less inflated bulla with only one infralaminal aperture and from C. dissimilis by its small compact test and bulla with just one infralaminal aperture. C. globiformis has a spherical-shaped test with a low, slightly inflated bulla with small circular, infralaminal apertures.

NB The short diagnoses are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus. They have initially been copied from the diagnostic characters/distinguishing features sections of the Eocene and Paleocene Atlases, they will be edited as the site is developed.


Diagnostic characters: Catapsydrax unicavus is distinguished from C. africanus by its less inflated bulla with only one infralaminal aperture and from Catapsydrax dissimilis by its small compact test and bulla with just one infralaminal aperture. Catapsydrax globiformis has a spherical-shaped test with a low, slightly inflated bulla with small circular, infralaminal apertures. [Olsson et al. 2006]

Wall type: Cancellate, apparently spinose, ruber/sacculifer-type wall texture, generally with heavy gametogenetic calcification. [Olsson et al. 2006]

Test morphology: Low trochospiral, lobulate test with 4 chambers in the final whorl. Chambers globular, embracing, increasing rapidly in size with a small globular, slightly inflated bulla extending over the umbilicus; wall thickened by gametogenetic calcite in adult specimens; in spiral view 4 globular chambers increasing rapidly in size; sutures straight to slightly curved, moderately depressed; in umbilical view 4 globular chambers, with a slightly inflated bulla that has one infralaminal aperture with a continuous, thickened imperforate rim, sutures straight, moderately depressed; in edge view ovoid in shape with small bulla. [Olsson et al. 2006]

Size: Holotype maximum diameter 0.22 mm,thickness 0.17 mm. [Olsson et al. 2006]

Character matrix

test outline:Lobatechamber arrangement:Trochospiraledge view:Inequally biconvexaperture:Umbilical
umb chamber shape:Globularcoiling axis:Lowperiphery:N/Aaperture border:Thick lip
sp chbr shape:Globularumbilicus:Narrowperiph margin shape:Broadly roundedaccessory apertures:None
umbilical or test sutures:Moderately depressedumb depth:Deepwall texture:Spinoseshell porosity:Finely Perforate: 1-2.5µm
spiral sutures:Moderately depresseddiameter mm:0.22width mm:breadth mm:0.17
final-whorl chambers:4.0-4.0

Biogeography and Palaeobiology

Geographic distribution: Global. [Olsson et al. 2006]
Aze et al. 2011 summary: Cosmopolitan; based on Olsson et al. (2006c)

Isotope paleobiology: Stable isotope studies (Poore and Matthews, 1984) suggest that C. unicavus occupied a deep-dwelling planktonic habitat in which population sizes were never large. [Olsson et al. 2006]
Aze et al. 2011 ecogroup 4 - Open ocean sub-thermocline. Based on very light δ13C and very heavy δ18O. Sources cited by Aze et al. 2011 (appendix S3): Poore & Matthews (1984); Pearson et al. (2001a)

Phylogenetic relations: Catapsydrax unicavus is probably derived from a subbotinid in the early Eocene by developing a bulla that extends over the umbilicus. [Olsson et al. 2006]

Most likely ancestor: Globorotaloides quadrocameratus - at confidence level 4 (out of 5). Data source: Olsson et al. 2006 f5.1.

Biostratigraphic distribution

Geological Range:
Notes: Zone E2 to N6. [Olsson et al. 2006]
Last occurrence (top): within N6 zone (17.54-17.59Ma, top in Burdigalian stage). Data source: Olsson et al. 2006 f5.1
First occurrence (base): within E2 zone (55.20-55.81Ma, base in Ypresian stage). Data source: Olsson et al. 2006 f5.1

Plot of occurrence data:

Primary source for this page: Olsson et al. 2006 - Atlas of Eocene Planktonic Foraminifera, chapter 5, p. 75


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Catapsydrax unicavus compiled by the pforams@mikrotax project team viewed: 20-1-2018

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