Catalog - Globigerinita glutinata flparkerae

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Globigerinita glutinata flparkerae

Citation: Globigerinita glutinata flparkerae Brönnimann & Resig 1971

Type specimens: Plate 23, Figures 1 through 4; Plate 50, Figure 6; Text-figure 15

Type repository: n/a relacement name

Bermúdez (1961, p. 1232, pl. 10, fig. 10, 11) introduced Globigerinoides parkerae for minute trochoid forms possessing a thin wall, a glossy, smooth to very finely hispid or pustulate surface and a single supplementary aperture in the spiral suture of the last-formed chamber. In our material we find that this supplementary aperture varies from a rounded to an elongate opening, and we find also specimens referable to this subspecies which develop more than one sutural opening in the spiral suture of the final chamber (Plate 50, Figure 6). This opening (or openings) is usually provided with a very thin upturned, imperforate and faintly pustulate rim. We have illustrated a specimen with a single sutural aperture on Plate 23, Figure 1. The specimen shown on Plate 23, Figures 2 and 4, may have a second sutural opening at the intersection of the suture between penultimate and antepenultimate chambers and the spiral suture.

Blow (1969) figured on Plate 22, Figure 1, a specimen with a typical elongate slit-like supplementary aperture with a weak but distinct lip along the entire spiral suture, and on Plate 22, Figure 3, a specimen with a somewhat reduced supplementary aperture. Plate 22, Figure 4, shows one of his specimens with two supplementary apertures at the intersections between spiral suture and the radial suture between ultimate and penultimate chamber, and that between the fourth and the fifth chamber. Also, Parker (1962, p. 249) noticed these different supplementary apertures in forms referred by her to Globigerinita glutinata. She wrote that "Specimens may have a single primary aperture (Globigerinita glutinata juvelinis in the present usage); the last chamber may be attached in such a way as to divide the aperture into two or three parts; there may be a single or double dorsal aperture(s) or none, some have a multiple-apertured umbilical bulla (Globigerinita glutinata in the present usage); there may be additional bullae over the dorsal aperture(s)".

The variability in the shape and the number of the dorsal supplementary aperture in Globigerinita glutinata flparkerae suggests that this opening is not a homologue of the sutural supplementary apertures of Globigerinoides which are invariably at the intersection of spiral and radial sutures. The presence of supplementary dorsal sutural openings does not refer a globigerine trochospire automatically to Globigerinoides Cushman, 1927. On the basis of the outer wall aspects of Bermúdez' Globigerinoides parkerae we feel that it should be assigned to the group of forms represented by Globigerinita glutinata glutinata (Egger), 1893, Globigerinita glutinata juvenilis (Bolli), 1957, and Globigerinita uvula (Ehrenberg), 1861. This group of globigerinitas represents a genetic unit characterized by similar coiling and similar outer wall features. It needs further morphologic investigation with the help of scanning micrographs and stratigraphic evaluation. In the present writers' opinion this group differs from the globigerinitas with umbilical "bulla" as represented by "Globigerinita" dissimilis, "Globigerinita" pera, "Globigerinita" unicava, etc. which, however, have not been generically separated in this paper.

As the name parkerae has already been used by Loeblich and Tappan (1957) within the genus Globigerinita for a form described in 1954 by Parker from the Recent of the Gulf of Mexico as Globigerina sp., we propose to change the name introduced by Bermudez (1961) from parkerae to flparkerae.

The outer wall formations of the Globigerinita glutinata group of forms is characterized by individual composite-structured pustules which never develop a polygonal meshwork. On the final chamber, which is usually thin-walled and fragile as shown by the scanning micrograph Plate 50, Figure 3, they are irregularly distributed and widely spaced, and of very different dimensions. The wall surface between the pustules has a finely granular appearance and seems to be perforated by numerous pinpoint-like pores. The individual, more or less bluntly rounded pustules do not seem to be "canaliculate". On the earlier chambers of the trochospire, the individual pustules are larger, more pointed, and on the earliest chambers they almost touch each other. On the younger chambers they.are still irregularly and widely spaced, and on the penultimate chamber of the specimen, Plate 50, Figures 2 and 4, minute pustules occur between the larger ones in the region toward the spiral suture. Pinpointlike wall pores are more easily detected on this chamber; on the earlier trochospiral chambers they surround the large pustules not vice versa as in most Globigerinacea. We further noticed that the trochospiral beginning is never well exposed, probably due to accumulation of secondary shell substance. This may also be the reason why on the "first" chamber, as shown on Plate 50, Figure 1, and Figure 4, the number of pustules and of wall pores is reduced.

Stratigraphic Range: Globigerinita glutinata flparkerae has been recorded in Hole 62.1, from Corel, Section 1 to Core 35, Section 5, that is, over a range from N13 to N23. It is quite possible that it ranges stratigraphically further downwards than is here indicated.

Note this is a replacement name for Globigerinoides parkerae Bermudez 1961, proposed on the basis that the species should be placed in Globigerinita and that this would make it a homonym of Globigerinita parkerae Loeblich & Tappan 1957

References:

Brönnimann, P. & Resig, J. (1971). A Neogene globigerinacean biochronologic time-scale of the southwestern Pacific. Initial Reports of the Deep Sea Drilling Project. 7(2): 1235-1469. gs O

CATALOG OF ORIGINAL DESCRIPTIONS: Globigerinita glutinata flparkerae Brönnimann & Resig 1971

Globigerinita glutinata flparkerae

References:

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