Geonettia waltonensis, a new goniodomacean dinoflagellate from the Pliocene of the North Atlantic region, and its evolutionary implications

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doi: 10.1666/0022-3360(2000)074<0812:GWANGD>2.0.CO;2
Author(s): Head, Martin J.
Author Affiliation(s): Primary:
University of Cambridge, Department of Geography, Cambridge, United Kingdom
Volume Title: Journal of Paleontology
Source: Journal of Paleontology, 74(5), p.812-827. Publisher: Paleontological Society, Lawrence, KS, United States. ISSN: 0022-3360 CODEN: JPALAZ
Note: In English. 44 refs.; illus., incl. 1 table, sketch map
Summary: A new species of the unusual dinoflagellate cyst genus Geonettia de Verteuil and Norris, 1996a is here described from the Pliocene of the western North Atlantic and eastern England. Geonettia waltonensis new species is only the second species to be formally described for this genus, whose type, G. clineae de Verteuil and Norris, 1996a, has a range of Miocene through Pliocene. Geonettia is a gonyaulacalean, goniodomacean genus of the subfamily Pyrodinioideae and is closely related to Eocladopyxis Morgenroth, 1966 and Capisocysta Warny and Wrenn, 1997, also found in the Cenozoic. However, Geonettia is the only known dinoflagellate cyst genus to have plates that dissociate extensively on both epi- and hypocyst during excystment. Geonettia waltonensis has this style of excystment, but its hypocystal tabulation is more akin to Capisocysta lata Head, 1998a than to G. clineae. Comparison of tabulation and other morphological features suggests that during the late Miocene, Capisocysta lata evolved from Geonettia waltonensis or a closely related species through failure of its epicystal plates to dissociate. Geonettia waltonensis probably did not evolve directly from G. clineae but may represent a separate lineage within Geonettia that arose during the Miocene.
Year of Publication: 2000
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 09 Paleontology, Paleobotany; Atlantic Ocean; Biologic evolution; Cenozoic; DSDP Site 603; Deep Sea Drilling Project; Dinoflagellata; East Anglia; England; Essex England; Europe; Geonettia waltonensis; Great Britain; IPOD; Leg 105; Leg 93; Leg 95; Microfossils; Neogene; New taxa; North Atlantic; ODP Site 645; Ocean Drilling Program; Palynomorphs; Pliocene; Suffolk England; Tertiary; United Kingdom; Western Europe
Coordinates: N352939 N352940 W0700142 W0700143
N702730 N702730 W0643924 W0643924
N515500 N523500 E0014500 W0003000
N513000 N521000 E0011500 E0000000
Record ID: 2001052591
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