Taxonomic revision and evolutionary classification of the biserial Cretaceous planktic foraminiferal genus Laeviheterohelix Nederbragt, 1991

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Author(s): Georgescu, Marius Dan
Author Affiliation(s): Primary:
University of Calgary, Department of Geoscience, Calgary, AB, Canada
Volume Title: Revista Mexicana de Ciencias Geológicas
Source: Revista Mexicana de Ciencias Geológicas, 26(2), p.315-334. Publisher: Universidad Nacional Autónoma de México, Instituto de Geología, Queretaro, Mexico. ISSN: 1026-8774
Note: In English. 50 refs.; illus., incl. 1 table
Summary: Taxonomic re-evaluation of the Upper Cretaceous serial planktic foraminiferal genus Laeviheterohelix Nederbragt, 1991 revealed that the genus is polyphyletic. Three genera are recognized, two new, Steineckia n. gen. and Fleisherites n. gen., and one emended, namely Laeviheterohelix. Steineckia n. gen. is the oldest serial planktic foraminifer with pore mounds and it appears restricted to the upper Turonian sediments of the South Atlantic (Falkland Plateau). It includes only the type species, Steineckia steinecki n. sp. The genus Laeviheterohelix is revised and according to the emendation proposed here consists only of species from the Upper Coniacian-Campanian stratigraphic interval: L. pulchra (Brotzen, 1936)--emended and L. reniformis (Marie, 1941)--emended. The species with smooth tests and occasionally with incipient costae of the Maastrichtian are included within Fleisherites n. gen. Its type species is Fleisherites glabrans (Cushman, 1938). This newly proposed taxonomic framework is based on detailed, scanning electron microscope-based observations on the test ornamentation and ultrastructure. The taxonomic significance of the presence/absence of the pore mounds, periapertural pustulose area and pore mound size is of paramount importance in documenting the iterative evolution pattern in the serial planktic foraminifera with smooth test wall or ornamented with pore mounds.
Year of Publication: 2009
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 10 Paleontology, Invertebrate; Atlantic Coastal Plain; Atlantic Ocean; Biogeography; Biologic evolution; Biostratigraphy; Blake Nose; Blake Plateau; Classification; Cretaceous; DSDP Site 111; DSDP Site 305; DSDP Site 356; DSDP Site 357; DSDP Site 384; DSDP Site 463; DSDP Site 511; Deep Sea Drilling Project; Distribution; Electron microscopy data; Fleisherites; Fleisherites glabrans; Foraminifera; Globigerinacea; Heterohelicacea; Heterohelicidae; IPOD; Invertebrates; Laeviheterohelix; Laeviheterohelix pulchra; Laeviheterohelix reniformis; Leg 113; Leg 12; Leg 122; Leg 171B; Leg 174AX; Leg 32; Leg 39; Leg 43; Leg 62; Leg 71; Mesozoic; Microfossils; Micropaleontology; Morphology; New taxa; North Atlantic; ODP Site 1049; ODP Site 1050; ODP Site 1052; ODP Site 689; ODP Site 690; ODP Site 761; ODP Site 762; Ocean Drilling Program; Ontogeny; Ornamentation; Phylogeny; Planktonic taxa; Pore mounds; Protists; Range; Revision; Rotaliina; SEM data; Shells; South Atlantic; Steineckia; Steineckia steinecki; Taxonomy; Tests; United States; Upper Cretaceous
Coordinates: N402139 N402139 W0513948 W0513948
S300015 S300015 W0353335 W0353335
N212101 N212101 E1744004 E1744004
Record ID: 2018091637
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