CATALOG OF ORIGINAL DESCRIPTIONS: Globorotalia (Hirsutella) theyeri Fleisher 1974

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 (Hirsutella) -> Globorotalia (Hirsutella) theyeri
Other pages this level: G. (Hirsutella) eleonorae, G. (Hirsutella) scitula planaria, G. (Hirsutella) theyeri,

Globorotalia (Hirsutella) theyeri

Citation: Globorotalia (Hirsutella) theyeri Fleisher 1974
Rank: species
Type age: late Quaternary(N.23?)
Type sample and level: DSDP 219-1-1, 110 112 cm.

Linked specimens: USNM-211460 USNM-211459 USNM-211458 USNM-211457

Current identification/main database link: Globorotalia theyeri Fleisher, 1974


Original Description
The test is large and planoconvex to unequally biconvex, with up to 16 chambers arranged in a low trochspire. The final whorl consists of 4 to 5 chambers, typically with 4 in smaller tests and 4½ in larger specimens. In outline, the test is strongly lobate and the chambers flare markedly in the final whorl. This is particularly true of the final few chambers. The test wall is thin, translucent, and finely and uniformly perforate. The peripheral margin is highly acute and is marked by a thin imperforate keel that is difficult to observe in reflected light. In most speciments, this keel is somewhat discontinuous. It is well developed along the posterior peripheral margin of each chamber (Plate 13, Figures 3, 5), becomes weaker toward the anterior end of the same chamber, and may disappear altogether. The progression on each chamber is from an imperforate raised carina, to a perforate raised carina, and finally to a perforate and rounded margin (Plate 13, Figure 4). On small specimens (Plate 12, Figure 9) this discontinuous development may occur only on the last chamber. The early whorls are somewhat obscured by secondary calcite deposits. The dorsal surface is slightly convex, but appears relatively flat in contrast to the inflated ventral surface. The chambers are only slightly inflated dor sally. The dorsal intercameral sutures are strongly recurved, and both intercameral and spiral sutures are distinctly depressed, particularly within the final whorl. The ventral side is much more elevated than the dorsal, and the chambers are inflated to a much greater degree. Ventral sutures are radial and straight, but may become slightly recurved near the periphery. The umbilicus is relatively large, open, and deep. Small conical crystallites or pustules are present on the chamber walls and keel in the umbilical region, but are more common on ventral than on dorsal surfaces. The apertural face is steep, but the transition from ventral wall to apertural face is rounded and gradual. The aperture is an open arch at the base of the apertural face and extends from the umbilicus almost to the periphery. It is immediately bordered by a distinct but thin lip and surrounded by a broad imperforate region covering nearly half of the apertural face. Almost all observed specimens are sinistrally coiled.

Size: The maximum diameter of the holotype is 0.79mm; the axial elevation is 0.32 mm.

Etymology: This species is named for Dr. Fritz Theyer, formerly of the University of Southern California and presently at the University of H awaii.

Extra details from original publication

Remarks: The flared and very loosely appressed chambers of the final whorl and the distinctly flattened dorsal surface distinguish G. (H.) theyeri from many other late Neogene species. It differs from G. (H.) scitula s.l. in possessing as well a thin peripheral keel, and from G. (H.) hirsuta in the much flatter dorsal side. It may be separated from G. (H.) hirsuta praehirsuta and G. (H.) margaritae by its much greater ventral, and lesser dorsal, elevation and by possessing
a relatively large ventral umbilicus. From G. {Truncorotalia) crassaformiss.l., G. (T.) aemiliana, G. (T.) crotonensis, and similar species, G. (H.) theyeri may be distinguished by its more flattened and less anguloconical shape, and by the much greater flare and distal extension of the chambers in the final whorl.
This form appears to have been recorded on several occasions, but not distinguished taxonomically from other species. Parker has referred the form to G. hirsuta (1962, pi. 5, figs. 12, 14) and to G. sp. B (Parker and Berger, 1971, p. 101) and has recorded it from the surface sediments of the tropical Indian and South Pacific oceans. Vincent (1972) recognized it as G. crassula in late Quaternary associations from the Mozambique Channel. It appears that G. (H.) theyeri may be restricted to tropical Indo Pacific regions. 

References:

Fleisher, R. L. (1974a). Cenozoic planktonic foraminifera and biostratigraphy, Arabian Sea, Deep Sea Drilling Project, Leg 23A. Initial Reports of the Deep Sea Drilling Project. 23: 1001-1072. gs :: ::


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Globorotalia (Hirsutella) theyeri compiled by the pforams@mikrotax project team viewed: 5-6-2020

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