Catalog - Globigerina gautierensis

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.

Globigerina gautierensis

Citation: Globigerina ? gautierensis Bronnimann 1952

Type species: Globigerina gautierensis

Type specimens: PR 4816 Holotype: T.L.L.Cat.Nos.144455,168920.Text figs.2a-c.All appr.X80.Plate 1,figs.1-3.

Type sample (& lithostrat): Globotruncana apenninica zone,Gautier formation

Type age (chronostrat): Upper Cretaceous

Type locality: Globotruncana apenninica zone,Gautier formation,Upper Cretaceous, Trinidad,B.W.I.

Type repository: Washington; USNM

The test is a low trochoidal spiral with 5 to 6 chambers in the adult. The trochoidal arrangement is so weak that the apertural aspect is almost that of Globigerinella. The chambers are much oppressed, subglobular and increase gradually in size. The end chamber is often strongly inflated and broad in apertural view and tends to shift toward the umbilical side. The more or less flat spiral side shows about 12 chambers arranged in 2 volutions. The deep and well-defined subcircular umbilicus is rather small compared with that of 6-chambered Rugoglobigerinas. The sutures are straight and not much depressed. The outline of the test, therefore, is only weakly lobulate. The large arcuate aperture is interiomarginal. The walls are finely perforate, and the surface is ornamented with small papillae which are stronger on the early ontogenetic chambers. The surface of the end chamber appears to be almost smooth. The species is random coiling.

The maximum diameter of paratypes ranges from 0.375mm.to 0.4mm. Holotype: Maximum diameter 0.412mm.Diameter of umbilicus 0.05mm. End chamber:radial diameter 0.15mm.;tangential diameter 0.175mm;thickness 0.177mm.

The name of the new species is derived from the Gautier River. Eastern Central Range, Turure area.

Remarks. Globigerina gautierensis differs from the morphologically-related, slightly compressed G. cretacea by the subglobular to globular, oppressed chambers, which are more numerous in the adult, and by the distinctly less lobulate outline. The low trochoid Globigerina planispira Tappan 1940, from the Grayson formation, Washita group.Lower Cretaceous, Denton County, Texas, differs from G. gautierensis by its bulbous chambers with a smooth surface. G. portsdownensis Williams-Mitchell 1948, from the Cenomanian, Upper Cretaceous, Portsdown No. 1 well, Hampshire, England, is much more trochoidal than any of the Globigerinas of the Gautier formation.

Nauss (1947, pp. 336-337, pl.49, figs, 11a-c) introduced Globigerina loetterlei (originally misprinted G.loetterli) from the Upper Cretaceous Lloydminster shale, Vermilion area. Alberta, Canada. This form is associated with Globigerina cretacea d'Orbigny and with Guembelina globulosa (Ehrenberg). G.loetterlei resembles G. gautierensis in its weakly trochoidal spiral test of only slightly lobulate outline. Only ornamentation and size differentiate the 2 forms which very likely belong to the same group of Cretaceous Globigerinas. G.loetterlei Nauss has also been recorded from the Upper Cretaceous of Alaska (Tappan, 1951, pp.4-5, pl.1, figs, 19a-c). The Alaskan specimens appear to be rather small (greatest diameter 0.18-0.29mm.) in comparison with those from Alberta (greatest diameter 0.4-0.7mm.).

Due to the lack of information regarding the occurrence of Globotruncanas in the Upper Cretaceous of Alaska and of Canada, it is at present not possible to draw any conclusions regarding the correlation of these deposits and the Trinidad Upper Cretaceous.

The 5-chambered rugose Globigerina from the Upper Cretaceous White Chalk of Antigua, reported by Cushman (1931, P-44, pl-6, figs.6a-c) as G. cretacea apparently belongs to the genus Rugoglobigerina. According to Cushman's description there is frequently a thin, platelike structure across the umbilical region. The figured specimen is small for the genus (0.28mm.) and possibly represents Rugoglobigerina reicheli hexacamerata or a variant of this species. The figured specimen (pl.6, figs.5a-b) with 6 chambers in the adult and a low trochoidal spiral has to be assigned to the same species.

In this connection it should be emphasized that the White Chalk from which Cushman's Foraminifera originate is not indigenous of Antigua, but was imported as ballast from Europe during the time the water well of Cassada Gardens was being dug. Dr. H.G.Kugler, who kindly drew the writer's attention to this fact, states in a private report on the Geology of Antigua :
"L.1303 Cassada Garden The famous well of Cassada Garden is situated in a low undulating savannah near the golf course. Ever since Cushman has reported a Cretaceous fauna of exactly the same assemblage as known from the French Chalk of the Paris basin, there were doubts about the existence of such Cretaceous in Antigua. Senn (1940) used the reported Cretaceous to support one of his theories. Trechmann (1941) doubted the occurrence of the chalk. In 1941, the geologist Cleaves reported to the writer that Mr. Forrest, who had supplied the samples to Dr.Cushman, was in England during the deepening of the well. There is little doubt that the rock had been brought across the sea in ballast for "sweetening"the very salty water of the well."

References:

Brönnimann, P. (1952c). Globigerinidae from the Upper Cretaceous (Cenomanian-Maestrichtian) of Trinidad, B. W. I. Bulletins of American Paleontology. 34(140): 1-70. gs

CATALOG OF ORIGINAL DESCRIPTIONS: Globigerina ? gautierensis Bronnimann 1952

Globigerina gautierensis

References:

Add Comment

Comments