Catalog - Globigerinelloides impensus

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Globigerinelloides impensus

Citation: Globigerinelloides impensus Sliter 1977

Type age (chronostrat): Maastrichtian

Type locality: Holotype (fig. 1) and paratypes (figs. 2, 3) from a depth of 61-63 cm. in Section 2 of Core 13 (cored interval 137.0-146.5 m. below the sea floor) in Hole A if Site 327 of Deep Sea Drilling Project Leg 36, drilled in waters 2400 meters deep at lat. 50 deg

Type repository: Washington; USNM

Test free, planispiral, biumbilicate, partially evolute, equatorial periphery lobate, axial periphery rounded. Chambers 8 to 10 in final whorl, equatorially flattened, increasing gradually in size, final chambers generally ovate, ultimate chamber often reduced in size. Sutures distinct, depressed radial, straight to gently curved. Wall calcareous, finely perforate, surface pustulose on early chambers of final whorl, final few chambers nearly smooth. Aperture a broad, low, interiomarginal, equatorial arch, pordered above by a narrow lip. Relic apertures and relic apertural flaps distinct. From Ellis & Messina: "Test free, planispiral, biumbilicate, partially evolute, equatorial periphery lobate, axial periphery rounded. Chambers 8 to 10 in final whorl, equatorially flattened, increasing gradually in size, final chambers generally ovate, ultimate chamber often reduced in size. Sutures distinct, depressed radial, straight to gently curved. Wall calcareous, finely perforate, surface pustulose on early chambers of final whorl, final few chambers nearly smooth. Aperture a broad, low, interiomarginal, equatorial arch, bordered above by a narrow lip. Relic arpertures and relic apertural flaps distinct. "Largest diameter of holotype 0.32 mm. Paratypes range from 0.28 to 0.43 mm. "Remarks. - This large plantonic species characterized by the numerous flattened chambers occurs consistently in the late Campanian smaples of Leg 36. Globigerinelloides impensus Sliter somewhat resembles Globigerinelloides alvarezi (Etemod Olvera) [Planomalina alvarezi, 1959] originally described from the Campanian-Maestrichtian of Mexico. It differs, however, in the larger size, compressed test, slightly curved sutures, and less highly arched aperture. "The new species differs from Globigerinelloides bolli Pessagno in its larger size, more numerous, more compressed chambers, gently curved sutures, and pustulose surface."

References:

Sliter, W. V. (1977). Cretaceous foraminifers from the southwestern Atlantic Ocean, Leg 36, Deep Sea Drilling Project. Initial Reports of the Deep Sea Drilling Project. 36: 519-573. gs

CATALOG OF ORIGINAL DESCRIPTIONS: Globigerinelloides impensus Sliter 1977

Globigerinelloides impensus

References:

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