Catalog - Globigerinella japonica

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Globigerinella japonica

Citation: Globigerinella japonica Takayanagi 1960

Type specimens: : holotype #74975 [holotype lost, possibly in 1980 earthquake according to H. Nishi, person. comm. 11-19-2018]; paratypes #74894

Type sample (& lithostrat): Upper part of the Usobushinai Fm.

Type age (chronostrat): Type specimens from Lower Hetonaian (=mid-upper Campanian); range upper Urakawan (=Santonian) to lower Hetonaian (=mid-upper Campanian)

Type locality: River cliff, Wakka-uebetsu River, Teshio Province, Hokkaido, Japan.

Type repository: Tohoku University, Sendai, Japan;

Test planispiral, biumbilicate, evolute, peripheral margin lobulate; chambers ovate to nearly spherical, increasing in size as added, about 12-17, arranged in two to two and a half whorls, usually five to seven in last whorl; sutures distinctly depressed; wall calcareous, finely perforate, surface finely hispid in well preserved specimens; aperture an interiomarginal, equatorial, simple low arch, bordered above by a narrow lip.

Paratype maximum diameter 0.14 to 0.18 mm, maximum breadth 0.6 to 0.8 mm

Takayanagi, 1960: "This species resembles the figured specimens assigned to "Globigerinella' aspera (Ehrenberg) by various authors. Although there was no description or good illustration in the original definition of 'G.' aspera, its trochospiral coiling is recognized at least in the early stage by the figures of the subsequent authors. In this feature the present form differs obviously from the latter. However, the generic position of this form is a question. Recently Bolli et al. (1957) regarded Globigerinella as a junior synonym of Hastigerina Thomason, and the present writer agrees. Further they adde as follows: "Mesozoic species referred to Globigerinella upon close examination will be seen to belong either to Planomalina Loeblich and Tappan, Biglobigerinella Lalicker, or to Globigerinelloides Cushman and ten Dam." Nevertheless, as stated in the foregoing description, the present form shows neither a trace of relict secondary apertures as Globigerinelloides or Planomalina, nor two paired chambers in the later portion as Biglobigerinella. Furthermore, all of the present specimens examined (more than 50) cannot be assumed to be immature forms, though Biglobigerinella has simple planispiral chambers in the early stages.

References:

Takayanagi, Y. (1960). Cretaceous foraminifera from Hokkaido, Japan. Science Reports of the Tohoku University. 32(1): 1-154. gs

CATALOG OF ORIGINAL DESCRIPTIONS: Globigerinella japonica Takayanagi 1960

Globigerinella japonica

References:

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