CATALOG OF ORIGINAL DESCRIPTIONS: Globorotalia (Turborotalia) mendacis Blow 1969

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 (Turborotalia) -> Globorotalia (Turborotalia) mendacis
Other pages this level: G. (Turborotalia) acostaensis pseudopima, G. (Turborotalia) acostaensis tegillata, G. (Turborotalia) akersi, G. (Turborotalia) archeocompressa, G. (Turborotalia) bauerensis, G. (Turborotalia) cifellii, G. (Turborotalia) exserta, G. (Turborotalia) galapagosensis, G. (Turborotalia) griffinae, G. (Turborotalia) hansbollii, G. (Turborotalia) humerosa praehumerosa, G. (Turborotalia) incisa, G. (Turborotalia) longiapertura, G. (Turborotalia) mendacis, G. (Turborotalia) nkbrowni, G. (Turborotalia) oceanica, G. (Turborotalia) palpebra, G. (Turborotalia) parkerae, G. (Turborotalia) peripheroacuta, G. (Turborotalia) peripheroronda, G. (Turborotalia) permicra, G. (Turborotalia) planispira, G. (Turborotalia) pliocenica, G. (Turborotalia) praecentralis, G. (Turborotalia) praeoscitans, G. (Turborotalia) pseudoimitata, G. (Turborotalia) pseudoinconstans, G. (Turborotalia) pseudokugleri, G. (Turborotalia) pseudopumilio, > >>

Globorotalia (Turborotalia) mendacis

Citation: Globorotalia (Turborotalia) mendacis Blow 1969
Rank: species
Type locality: Holotype (figs. 5, 6) from a sample at 278 feet 7 inches depth in JOIDES drill-hole no. 3 (lat. 28 0 30' N., long. 77 0 3 1 ' W.) on the Blake Plateau, off the east coast of Florida; and figured paratype (figs. 7-9) from a sample at 275 feet 6 inches in the same drill-hole.
Type age: Upper Oligocene, probably lower part of Zone N.3 ( z Globigerina angulisuturalis Partial-range zone). Ranges from the upper part of Zone N. 2 (Upper Oligocene) to the lower part of Zone N.4 (Lower Miocene).
Holotype Repository: London, UK; NHM
Type & figured specimens: PM PF 49718

Linked specimens: London, UK; NHM (PM PF 49718) London, UK; NHM (PM P 49718)

Current identification/main database link: Paragloborotalia birnageae (Blow, 1959)


Original Description
Test small, very nearly equally biconvex, coiled in a low trochspire with about 13-15 chambers in the spire. Early chambers indistinct due to the strongly pustulate dorsal surface of the earlier whorls; 7 ½ chambers in the final whorl. Chambers slightly inflated both dorsally and ventrally with a smoothly rounded but sub-acute dorsal-peripheral margin. Chambers moderately embracing rather longer tangentially (anterior-posterior) than radially broad. Test tightly coiled with the spire opening slowly and regularly. The dorsal intercameral sutures are moderately incised but the pustulate nature of the dorsal surface covers the presumed incision of the earlier dorsal intercameral and spiral sutures. The dorsal intercameral sutures are recurved, posteriorly directed and slightly sinuous. Ventral intercameral sutures are directed sub-radially, straight to slightly sinuous. Umbilicus very small, almost closed. Aperture, a short slit-like opening, interiomarginal,
umbilical-extraumbilical. Wall coarsely perforate in a paratype with comparatively large pores; no distinct surface pits. Wall strongly pustulate in the holotype especially on the dorsal surface of the earlier chambers.

Size: Maximum diameter of holotype 0.26 mm.

Extra details from original publication
This taxon shows characters intermediate between those of Globorotalia (T.) kugleri Bolli and G. (T.) pseudokugleri Blow. G (T.) mendacis precedes these two latter forms in the stratigraphic record and it is believed to be the common ancestral form to both. G. (T.) mendacis differs from G. (T.) kugleri in having a more equally biconvex test, in having less tangentially elongate chambers with less recurved or retorse dorsal intercameral sutures and in having a more nearly closed umbilical depression. G. (T.) kugleri usually has a nearly flat dorsal surface, distinct dorsal intercameral sutures throughout the whole of the spire and little, if any, development of pustules either dorsally or ventrally. Further the aperture of G. (T.) kugleri is longer and has a more distinct lip than G. (T.) mendacis. The chambers of G. (T.) kugleri, in dorsal aspect, are more embracing, usually more numerous in the last whorl and have a distinct, rather narrow, wedge-shape appearance in ventral aspect as compared to those of G. (T.) mendacis. In axial view, the nearly flat dorsal surface of G (T.) kugleri gives the test a markedly plano-convex appearance as distinct from the nearly equally biconvex test of G. (T ) mendacis which also has somewhat inflated dorsal surfaces to the chambers.
 G. (T.) mendacis differs from G. (T.) pseudokugleri in having more strongly recurved dorsal intercameral sutures, a more nearly closed umbilical depression and more embracing but less inflated chambers, especially as seen in dorsal aspect. The test in axial profile shows a sub-acute biconvex appearance in G. (T.) mendacis but in G. (T.) pseudokugleri, the periphery is smoothly rounded with no trace of any sub-acute margin.

References:

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

Leckie, R. M. et al. (2018). Taxonomy, biostratigraphy, and phylogeny of Oligocene and Lower Miocene Paragloborotalia and Parasubbotina. In, Wade, B. S. , Olsson, R. K. , Pearson, P. N. , Huber, B. T. & Berggren, W. A. (eds) Atlas of Oligocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication. 46(Chap 5): 125-178. gs


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Globorotalia (Turborotalia) mendacis compiled by the pforams@mikrotax project team viewed: 9-4-2020

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