Taxonomic revision of the late Cenomanian planktonic Foraminifera Rotalipora greenhornensis (Morrow, 1934)

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doi: 10.2113/gsjfr.37.2.160
Author(s): Ando, Atsushi; Huber, Brian T.
Author Affiliation(s): Primary:
Smithsonian Institution National Museum of Natural History, Department of Paleobiology, Washington, DC, United States
Volume Title: Journal of Foraminiferal Research
Source: Journal of Foraminiferal Research, 37(2), p.160-174. Publisher: Cushman Foundation for Foraminiferal Research, Ithaca, NY, United States. ISSN: 0096-1191 CODEN: JFARAH
Note: In English. Includes appendix. 55 refs.; 1 table, 4 plates
Summary: Rotalipora greenhornensis has long been considered a representative planktonic foraminiferal species of the single-keeled Rotaliporinae of late Cenomanian age. Its taxonomic identity, however, is still ambiguous because this taxon has been distinguished by morphological criteria (numerous, strongly curved chambers, etc.), whereas the other species of Rotalipora are distinguished primarily by their apertural and ornamental characters (raised sutures, periumbilical ridges, etc.). The presence of strongly raised sutures throughout the umbilical and spiral sides has also been used to identify R. greenhornensis, but this criterion is troublesome as it also applies to its direct ancestor Rotalipora globotruncanoides. Reexamination of the holotype and observation of many topotypes and some North Atlantic and Pacific hypotypes reveals that, despite its remarkable morphological variability, R. greenhornensis is distinguishable by having umbilical sutures that are not fully raised, with the last several being depressed, and supplementary apertures that are umbilical in position and surrounded by a continuous series of closely-spaced periumbilical ridges. Moreover, reduction of the raised sutures tends to occur simultaneously on both the umbilical and spiral sides. Such apertural and ornamental characters of R. greenhornensis serve as its primary distinguishing features, allowing a clear-cut differentiation of this taxon from other species of Rotalipora, particularly the closely associated species R. globotruncanoides and plano-convex Rotalipora deeckei.
Year of Publication: 2007
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 10 Paleontology, Invertebrate; Atlantic Ocean; Cenomanian; Central Pacific; Cretaceous; DSDP Site 463; Deep Sea Drilling Project; Foraminifera; Globigerinacea; Greenhorn Limestone; Hodgeman County Kansas; Holotypes; IPOD; Invertebrata; Kansas; Leg 171B; Leg 62; Mesozoic; Microfossils; Morphology; North Atlantic; Northwest Atlantic; ODP Site 1050; Ocean Drilling Program; Ornamentation; Pacific Ocean; Planktonic taxa; Protista; Rotaliina; Rotalipora; Rotalipora greenhornensis; SEM data; Sutures; Taxonomy; United States; Upper Cenomanian; Upper Cretaceous
Coordinates: N375500 N381500 W0993700 W1001500
N300600 N300600 W0761406 W0761406
N212101 N212101 E1744004 E1744004
Record ID: 2007037440
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Abstract, Copyright, Cushman Foundation for Foraminiferal Research, Reference includes data from GeoScienceWorld, Alexandria, VA, United States

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