Citation: Globorotalia orientalis Maiya, Saito, & Sato 1976Rank: speciesType sample (& lithostrat): Sample My 3013, lower part of the Nishiyama Formation;Type age (chronostrat): PleistoceneType locality: collected along a tributary of the Toriyoshi River, approximately at latitude 37" 25' N ., longitude 138" 52' 40" E ., east of Jyoganji-machi. Nagaoka City. Niigata Prefecture; JapanType repository: Tokyo, Japan; National Science Museum
Original Description Test free. low trochospiral. moderately biconvex. nearly flat to weakly concave on the spiral side. convex to moderately vaulted on the umbilical side. equatorial profile distinctly lobulate. broadly subrhomboidal. without carina or pseudocarina; axial periphery broadly rounded. chambers slowly increasing in size. about 11 chambers in all. arranged in two and one-half tightly coiled whorls. usually four in the final whorl. sutures of the umbilical side slightly depressed. radial to slightly curved; sutures of the spiral side depressed. nearly radial to gently curved; wall calcareous. finely perforate. with distinct pustules covering the umbilical surface of the earlier chambers; umbilicus narrow but deep; aperture interiomarginal. umbilical to extraumbilical. low-arched opening at the base of narrow but distinct apertural face. with a thickened rimlike lip extending along the apertural opening. Size: Holotype (plate 1, figures 5a-5c). 0.46 mm.; paratype (plate 1, figures 1 a-1 b). 0.49 mm. Etymology: Extra details from original publication Remarks: This species closely resembles Globorotalia inflata praeinflata Maiya. Saito, and Sato, n, subsp ., and Globorotalia inflata inflata (d'Orbigny) in general morphology, lt is distinguished as a separate species by its low-arched aperture with a rimlike lip, subrhomboidal equatorial profile, and smaller, compact shell, it also differs from Globorotalia adamantea Saito in having more inflated chambers and in being flatter on the spiral side. This species also resembles Globorotalia miozea sphericomiozea Walters in having a lowarched aperture and a subrhomboidal equatorial profile. Our comparison of G. orientalis with topotypes of G. miozea sphericomiozea (see plate 2, figures 4a-4c), however, shows that the New Zealand species differs in having a more strongly vaulted umbilical side which gives a subtriangular axial profile and much less lobulate equatorial profile.
Occurrences: This species occurs abundantly in the lowermost part of the Nishiyama Formation of the Niigata oil field and in the lower Tentokuji Formation of the Akita oil field. Its stratigraphic range is limited to the Globigerina pachyderma (dextral)/Gioborotalia orientalis Zone. Editors' Notes
Maiya, S., Saito, T. & Sato, T. (1976). Late Cenozoic planktonic foraminiferal biostratigraphy of northwest Pacific sedimentary sequences. In, Takayanagi, Y. & Saito, T. (eds) Progress in Micropaleontology. Micropaleontology Press, New York 395-422. gs
Globorotalia orientalis compiled by the pforams@mikrotax project teamviewed: 4-12-2022