CATALOG OF ORIGINAL DESCRIPTIONS: Globorotalia (Acarinina) matthewsae Blow 1979

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.


Higher levels: pf_cat -> G -> Globorotalia (Acarinina) -> Globorotalia (Acarinina) matthewsae
Other pages this level: G. (Acarinina) appressocamerata, G. (Acarinina) broedermanni anapetes, G. (Acarinina) cuneicamerata, G. (Acarinina) matthewsae, G. (Acarinina) praeaequa, G. (Acarinina) praeangulata,

Globorotalia (Acarinina) matthewsae

Citation: Globorotalia (Acarinina) matthewsae Blow 1979
Rank: Species
Type locality: Holotype (pl. 170, fig. l) and nine paratypes (pl. 170, figs. 2-9; pl. 203, figs. 3, 4; pl. 204, 205) from Kilwa, Tanzania, B. P. site RS 24; also two paratypes (pl. 179, figs l, 2) from DSDP Site 2 IA, core l, sect. 4, 148-150 cm, Rio Grande Rise, and one paratype (pl. 187, fig. 5) from DSDP site 19, core 9, sect. 6, 148-150 cm, lat. 28 0 32.08' S., long. 23 0 40.63' W., west slope of Mid-Atlantic Ridge, both in the central South Atlantic Ocean.
Type age (chronostrat): Middle Eocene, middle Lutetian, Zone P.11 (Globigerapsis kugleri Zone); ranges between Upper Paleocene, upper Ypresian, Zone P.9, to Middle Eocene, middle Lutetian, Zone P. 12.
Type specimens: Holotye PM PF 64572 Paratype PM PF 64799
Type repository: London, UK; NHM

Linked specimens: London, UK; NHM (64799) London, UK; NHM (PM PF 64572)

Current identification/main database link: Acarinina bullbrooki (Bolli 1957)


Original Description
The test is comprised of about 10-12 chambers coiled in a low but fairly tightly coiled, trochospire with four chambers in the last whorl. In dorsal aspect, the chambers are very much longer tangentially than radially broad to the extent that each of the chambers in the last convolution virtually comprises one side of the quadrate equatorial profile of the test. The chambers of the last convolution are closely set together and apressed but are not greatly embracing. The anterior and posterior peripheral margins of the later chambers show some slight lateral angularity but these chambers are not significantly disjunct. The dorsal intercameral sutures are subradial to very slightly recurved. In axial-apertural profile, the dorsal side of the test is seen to be sensibly flat but the ventral side is strongly vaulted and almost conic. In axial-apertural view, the chambers are asymmetrically lunate with the dorso-peripheral margin rounded to subacute. In ventral aspect, the chambers are wedge-shaped and the intercameral sutures are radially disposed and quite distinctly incised. The umbilicus is comparatively small but open and very deep with the primary aperture extending from it to about 2/3rds of the way to the periphery; the aperture is bordered by a well marked apertural lip. The walls of the chambers, especially over the ventral surfaces, which are strongly muricate, in a paratype (see plates 204,205) are hollow structures at least in part. There is no formation of either a circum-cameral nuricocarina or a continuous inter-chamberal peripheral muricocarina although there is a close packing of muricae over the periphery of some of the earlier chambers.

Size: Maximum diameter of holotype 0.34 mm.

Extra details from original publication
The paratypic specimens figured on pl. 170, figs. 2-9, illustrate a range of morphological variation of G. (A.) matthewsae Blow, 1979, which supplement the morphological identity of the new taxon. Fig. 2 shows an axial-apertural view of a paratype and pl. 203, fig. 3, illustrates further details of the umbilical muricae of this specimen which are seen to be long conical processes which are quite closely packed together. The ventral views given on pl. 170, figs. 3, 6 and 9, illustrate the range of variation seen in the ventral appearance of morphotypes referable to the new taxon. The paratype illustrated on pl. 170, fig. 4, shows the close packing of the peripheral muricae and further details of this paratype are shown on pl. 203, fig. 4, where some discontinuous sheet-like late stage calcification can be seen enveloping some of the peripheral muricae without interruption of the normal mural-pores.
"The paratype illustrated on pl. 179, fig. l, shows the dorsal appearance of a specimen with a part of a fifth chamber present in the last convolution of the test and the axial-apertural view shown of another paratype on pl. 179, fig. 2, also has a part of a fifth chamber in its final convolution. The paratype illustrated on pl. 187, fig. 5, from Zone P. 12, illustrates a feature seen near the end of the life-range of the taxon wherein the earlier part of the dorsal test is depressed below the level of the dorsal surfaces of the later chambers so that the dorsal side of the test is concave. In this stratigraphically late specimen, the coiling mode is tighter than usual and the chambers of the last convolution are more closely set, appressed and embracing than usually seen in the more typical specimens from slightly older horizons.
Of particular interest is that in matthewsae, as in some other acarininid taxa, the muricae are hollow structures at least in part. The wall of the test consists of layers (cf. pl. 204, fig. 4) but these layers do not necessarily extend from one chamber to its predecessor (cf. pl. 204, fig. 2 and pl. 205, figs. I and 2)."

References:

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


logo

Globorotalia (Acarinina) matthewsae compiled by the pforams@mikrotax project team viewed: 20-10-2020

Taxon Search:
Advanced Search

Short stable page link: http://mikrotax.org/pforams/index.php?id=130959 Go to Archive.is to create a permanent copy of this page - citation notes



Comments (0)

No comments yet on this page. Please do add comments if you spot any problems, or have information to share

Add Comment

* Required information
1000
Captcha Image
Powered by Commentics