This page provides data from the catalog of type descriptions. The catalog is sorted alphabetically. Use the current identification link to go back to the main database.
Linked specimens: London, UK; NHM (64380) London, UK; NHM (64446) London, UK; NHM (64382) London, UK; NHM (64365) London, UK; NHM (64363) London, UK; NHM (64423) London, UK; NHM (PM PF 64447) London, UK; NHM (64531) London, UK; NHM (64449) London, UK; NHM (64421) London, UK; NHM (64448) London, UK; NHM (64532)
Current identification/main database link: Acarinina cuneicamerata (Blow 1979)
The large test is composed of about 11-12 chambers coiled in a low, fairly lax, trochospire with 5 chambers presently preserved in the last whorl. The dorsal surfaces of the chamber are not inflated but are flattened with only slightly incised dorsal intercameral sutures which are subradially disposed. In dorsal aspect, the later chambers are almost equally dimensional being only very slightly longer tangentially than they are radially broad. However, the earlier chambers of the last convolution are distinctly longer tangentially than they are radially broad. The last 3 chambers of the final whorl do not increase rapidly in size as added. The equatorial profile is not distinctly lobulate but the anterior and posterior margins of each of the later chambers is slightly disjunct and literally angulate. In axial-apertural view, the dorsal side is seen to be nearly flat whilst the ventral side is vaulted and forms a truncated cone. The peripheral margin is rounded to subacute and there is no concentration of muricae over this margin or circum-camerally. In ventral aspect, the umbilicus is widely open and the ventral intercameral sutures are incised. The ventral surfaces of the chambers are moderately inflated and the chambers are not closely appressed but do slightly embrace each other especially in the earlier part of the test. Within the umbilicus, the relict apertures of the penultimate and antepenultimate chambers can be seen and these relict apertures of the penultimate and antepenultimate chambers can be seen and these relict apertures are bordered by a well marked apertural lip which is confluent to the well marked lip of the primary aperture. The primary aperture opens into the umbilicus and extends for about 2/3rds of the basal suture towards the peripheral margin. The ventral walls of the test especially are strongly muricate. .
Size: Maximum diameter of holotype 0.41 mm.
Extra details from original publication
The two paratypes figured on pl. 156, figs. I and 3 display the typical appearance of the axial-apertural view (fig. 3) and the dorsal view (fig. l) of the new taxon and these paratypic specimens may be regarded as circumscribing the typical 4 morphology of Globorotalia (Acarinina) cuneicamerata Blow, 1979. However, some other, probably more phylogenetically advanced, forms show a more extreme development of the coiling-mode and relative width of the umbilicus such as that shown in the paratype figured on pl. 156, fig. 4. This paratype possesses a very widely open umbilicus but retains the wedge-shaped (cuneiform) chambers which, peripherally, are somewhat laterally angulate and disjunct. In forms, such as this paratype in fig. 4, the last convolution of the test may possess between 6 and 8 chambers in the final whorl and this feature combined with the open umbilicus may lead to confusion of the taxon with G. (A.) aspensis (Colom) [Globigerina aspensis, 1954]. However, dorsally, the chambers of cuneicamerata show laterally angulate and slightly disjunct anterior and posterior margins, whereas in aspensis the chambers are smoothly rounded and not laterally angulate. In ventral aspect, cuneicamerata possesses distinctly wedge-shape (cuneiform) chambers whilst in aspensis the chambers are quite distinctly subglobular.
"The writer has illustrated a considerable number of paratypic specimens for his new taxon so as to illustrate the range of variation ascribed to the form. The specimens on pl. 146, fig. 6-8, are considered as phylogenetically rather primitive specimens but these forms show (figs. 7 and 8) the deeply incised ventral sutures and the tendency for the chambers to become peripherally disjunct. The apertural system of the specimen figured in axial-apertural view (fig. 6) is examined in more detail on pl. 203 fig. 5, where the apertural lip is seen to be very well marked. It should also be noted that these earlier (Zone P.9), phylogenetically primitive forms do not always show the dorsal flattening to the same extent as seen in the more typical and later specimens from Zone P. 10. The specimens illustrated on pl. 148, figs. 4-6, show the typical morphology of the taxon but do not show (fig. 5) the very widely open umbilicus of the extreme form seen on pl. 156, fig. 4, discussed above. Similarly, the paratypic specimens illustrated on pl. 153, figs. 1-4, also show some part of the range of variation ascribed to the new taxon, especially in the nature of the dorsal side (figs. I and 2) wherein the reduction of tangential length of the chambers can be seen in later ontogeny of the specimens. It should also be noted that this reduction of tangential length as compared to the radial breadth of the chambers in the last convolution of the test of cuneicamerata is not seen in the ontogeny of specimens referable to G. (A.) aspensis (Colom) where the proportionate increase in size of the chambers remains a virtually constant feature. The two paratypic specimens figured on pl. 165, figs. 4 and 7, should also be compared to the specimens of G. (A.) aspensis (Colom) figured on the same plate. Plate 165, fig. 4, shows the presence of small dorsal sutural openings which are sometimes seen in specimens referable to G. (A.) cuneicamerata Blow, 1979; these small dorsal openings are not considered as true dorsal supplementary apertures but as a result of the subsequent addition of later calcified test material over previously calcified but strongly muricate edges and surfaces. The ventral view given in fig. 7 shows a specimen with quite deeply incised intercameral sutures which are infilled with finely comminuted coccolith debris. Globorotalia (Acarinina) cuneicamerata Blow, 1979 represents a final end-specialisation of one side-branch of development from G. (A.) pseudopilensis via G. (A.) decepta. The other end-specialisation via G. (A.) decepta is Globorotalia (Acarinina) matthewsae Blow, 1979, which shows the virtual opposite set of trends to those that operated for the production of the cuneicamerata-morphotype. The subgeneric assignment of cuneicamerata to Acarinina, in preference to the assignment to Trun corotaloides, is maintained because the lateral angulation of the chambers never reaches the stage wherein the later chambers become so disjunct as to be separated one from another for more than one half of their radial breadth. Furthermore, although small, mainly dorsal, sutural openings occur in G. (A.) cuneicamerata these do not seem to deveiop into true dorsal supplementary apertures.
Berggren, W. A., Pearson, P. N., Huber, B. T. & Wade, B. S. (2006b). 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 V O 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
Berggren, W. A., Pearson, P. N., Huber, B. T. & Wade, B. S. (2006b). 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 V O
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
Globorotalia (Acarinina) cuneicamerata compiled by the pforams@mikrotax project team viewed: 25-1-2021
Short stable page link: http://mikrotax.org/pforams/index.php?id=130958 Go to Archive.is to create a permanent copy of this page - citation notes