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Species Globorotalia (Turborotalia) mendacis Blow 1969 | ||||||
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| Diagnosis / Definition: | ||||||
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Blow (1969): Description of holotype: Test small, very nearly equally biconvex, coiled in a low trochospire with about 13 15 chambers in the spire. Early chambers indistinct due to the strongly pustulate dorsal surface of the earlier whorls; A chambers in the final whorl. Chambers slightly inflated both dorsally and ventrally with a smoothly rounded but sub acute dorsalperipheral margin. Chambers moderately embracing rather longer tangentially (anteriorposterior) 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. Maximum diameter of holotype 0.26 mm. |
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| Discussion / Comments: | ||||||
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Blow (1969): Remarks: This taxon shows characters intermediate between those of G. (T.) kugleri BOLLi and G. (T.) Pseudokugleri, n. sp. 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. Stratigraphical Range: From the later parts of Zone N.2 (= P.21) to within the earlier part of Zone N.4. The form has been observed most commonly in sediments from deep sea cores but does occur in the land based sections of Barbados and the Solomon Islands. Holotype from the cored section of JOIDES hole no. 3, Blake Plateau, core sample at 278 ft. 7 ins; Zone N.3 (probably early part). |
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| Synonym list: | ||||||
| Blow (1969): 1969 Globorotalia (Turborotalia) mendacis Blow. - Blow : p.390 pl. 38, figs. 5-9
Quilty (1976): 1969 Globorotalia (Turborotalia) mendacis Blow. - Blow : p.390 pl. 38, fig. 5-9
1976 Globorotalia (Turborotalia) mendacis Blow. - Quilty : p.689 pl. 12, figs. 21-22
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| Was used in synonym list of: | ||||||
| References: | ||||||
Blow,W.H. (1969): Quilty,P.G.. (1976): |
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| Anonymous: Unedited TaxonConcept data | ||||||
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