CATALOG OF ORIGINAL DESCRIPTIONS: Globigerina pera Todd 1957
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Citation: Globigerina pera Todd 1957Rank: SpeciesType specimens: holotype (fig. 10), no. 623805; paratype (fig. 11), no. 623806. Type sample (& lithostrat): Hagman formation. Occurs also in the upper Eocene Densinyama formation.Type age (chronostrat): Upper EoceneType locality: Holotype (fig. 10) and paratype (fig. 11) from locality S385, northeast-central Saipan, Mariana Islands. Found also at five other Saipan localities.Type repository: Washington; USNM
Original Description "Test somewhat compressed, low spired. Chambers few, rapidly increasing in size as added; 3ÃÇÂ_ to 4 constituting the adult whorl, with a smaller and smoother supplementary chamber extending from the periphery downward over the umbilicus. Sutures deeply incised. Wall calcareous, perforate, covered by a fine-grain pattern of round pits [possibly the basis for delicate spines during the life of the animal] and stubby irregular apines. Aperture a single opening under the lip at the inner edge of the supplementary chamber that covers the umbilicus. Size: Length 0.55-0.65 mm.; width 0.48-0.55 mm.; thickness 0.35-0.48 mm. Extra details from original publication
This species is easily confused with the Oligocene species Globigerina dissimilis Cushman and Bermudez, which it superficially resembles. The distinction between the two species lies in the supplementary chamber, which in G. dissimilis is like a bridge open at both ends, over the umbilicus, but in the present species is like a pocket, open only at one end. In addition, this species is more compressed than G. dissimilis. In the pocketlike supplementary chamber, G. pera resembles Globigerina turgida Finlay as illustrated and described by Brönnimann (1952, p. 19, pl. 3, figs. 1-3) but is a more elongate and more strongly compressed form. Globigerina bakeri Cole, which occurs with the present species, also usually has a pocketlike supplementary chamber present, but G. bakeri is a larger, high-spired form with the last several chambers of nearly equal size.
Editors' Notes content migrated from chronos
References:
Brönnimann, P. (1952d). Trinidad Paleocene and lower Eocene Globigerinidae. Bulletins of American Paleontology. 34(143): 1-34. gs
Todd, R. (1957). Smaller foraminifera, in Geology of Saipan, Mariana Islands, Pt. 3, Paleontology. U.S. Geological Survey, Professional Paper. 280-H: 265-320. gsVO
Globigerina pera compiled by the pforams@mikrotax project teamviewed: 31-3-2023
holotype illus_962.jpg
Todd 1957 pl70 f10.JPG
Todd 1957 pl70 f11.JPG
holotype illus_962.jpg
Todd 1957 pl70 f10.JPG
Todd 1957 pl70 f11.JPG
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