Citation: Globigerina ridenda Voloshinova 1960Rank: speciesType specimens: pl. 29, fig. 8a-c, "original," type specimen, dorsal, ventral, and peripheral views, X 7 5.Type sample (& lithostrat): Figured "original" (fig. 8a-c) from the Upper Miocene, upper Okobykay FormationType age (chronostrat): Upper Miocene and also occurs in the lower PlioceneType locality: Figured "original" (fig. 8a-c) from Severnaya Okha; and also found at Okha, Zapadny Ekhabi, Nutovo, and Paromay; all along the east coast of Sakhalin island, U.S.S.R.Type repository: Leningrad; (VNIGRI), Leningrad, U.S.S.R.; figured "original" (fig. 8a-c), no. 120/454.
Original Description Translation from the Russian. - Test medium-sized, more or less inflated, irregularly shaped with a roughly lobate outline, usually rectangular or often triangular. Spire of 1-2 1/2 whorls. Initial part convex, formed by a small number of chambers that are often very unclear and displaced towards the periphery. In the last whorl are 3 1/2 chambers, loosely connected by short, deep sutures. The two chambers preceding the last one are the largest and are spherical. The last chamber is usually smaller than these two and when the test is viewed from the peripheral margin appears slightly flattened, and overhangs somehow the umbilical region. Umbilical area very narrow, since most of it is closed off by the closely connected, strongly inflated umbilical margins of the chambers in the last whorl. Aperture narrowly semilunate, fonned by the excised umbilical margin of the last chamber. Apertures of the preceding chambers not visible. Wall coarsely reticulate, rough. Size: [Dimensions, in mm. - Diameter 0.20-0.30: thickness 0.12-0.20. Etymology: Extra details from original publication Basis for erecting the species. - With its small last chamber bearing a narrow slit-shaped aperture the species described is somewhat reminiscent of Globigerina pachyderma (Ehrenberg) [Aristerospira pachyderma, 1861] (Ehrenberg, 1861 , K. Preuss. Akad. Wiss. Berlin, Monatsber., p. 303, pl. 1, fig. 4). It differs in the irregular outlines of the test and the more freely joined chambers, and also by the more coarsely reticulate wall. [Tests of Globigerina ridenda Voloshinova, with their rectangular outline, are very similar to certain specimens of G. quadrilatera Galloway and Wissler that have a small final chamber (Galloway and Wissler, 1927, Jour. Pal., vol. 1, no. 1, p. 44, pl. 7, fig. 11 ), but the last species typically has a broadly open, deep umbilicus, often with the apertures of all the chambers in the last whorl distinctly visible, while in G. ridenda the umbilicus is closed, and the aperture is narrow and slitlike.] Editors' Notes
Voloshinova, N. A. (1960). Novye neogenovye rotaliidy ostrova Sakhalin. In, Markovsky, B. P. (ed.) Novye vidy drevnihk rasteniy i bespozvonochnyhk SSSR, Chast Pervaya, vypusk 1, chasti 1. Vsesoyuznyy Nauchno-Issledovatel'skiy Geologicheskiy Institut,, Moscow 163-169. gs
Globigerina ridenda compiled by the pforams@mikrotax project teamviewed: 26-11-2022