Marsileaceae sporocarps and spores from the late cretaceous of Georgia, U.S.A.

dc.contributor.author

Lupia, R

dc.contributor.author

Schneider, H

dc.contributor.author

Moeser, GM

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Pryer, KM

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Crane, PR

dc.date.accessioned

2020-12-05T17:19:02Z

dc.date.available

2020-12-05T17:19:02Z

dc.date.issued

2000-01-01

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2020-12-05T17:19:00Z

dc.description.abstract

A new species provisionally assigned to the extant genus Regnellidium Lindm. (Regnellidium upatoiensis sp. nov.) is established for isolated sporocarps assignable to the heterosporous water fern family Marsileaceae. Three sporocarps and hundreds of dispersed megaspores were recovered from unconsolidated clays and silts of the Eutaw Formation (Santonian, Late Cretaceous) along Upatoi Creek, Georgia, U.S.A. The sporocarps are ellipsoidal and flattened, contain both megasporangia and microsporangia, and possess a two-layered wall - an outer sclerenchymatous layer and an inner parenchymatous layer. In situ megaspores are spheroidal, with two distinct wall layers - an exine, differentiated into two layers, and an outer ornamented perine also differentiated into two layers. The megaspores also possess an acrolamella consisting of six (five to seven) triangular lobes that are twisted. In situ microspores are trilete and spheroidal, with a strongly rugulate perine, and show modification of the perine over the laesura to form an acrolamella. Comparison of the fossil sporocarps with those of four extant species of Marsileaceae reveal marked similarity with Regnellidium diphyllum Lindm., particularly in megaspore and microspore morphology. If found dispersed, the in situ megaspores would be assigned to Molaspora lobata (Dijkstra) Hall and the microspores to Crybelosporites Dettmann based on their size, shape, and ornamentation. Regnellidium upatoiensis sp. nov. extends the stratigraphic range of the genus back to the Santonian, nearly contemporaneous with the first evidence of Marsilea, and implies that the diversification of the Marsileaceae into its extant lineages occurred in the mid-Cretaceous.

dc.identifier.issn

1058-5893

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1537-5315

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https://hdl.handle.net/10161/21853

dc.language

en

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University of Chicago Press

dc.relation.ispartof

International Journal of Plant Sciences

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10.1086/317567

dc.subject

Science & Technology

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Life Sciences & Biomedicine

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Plant Sciences

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Cretaceous

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heterospory

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Marsileaceae

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mesofossil

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paleobotany

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Regnellidium

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DAKOTA FORMATION

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PHYLOGENY

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KANSAS

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FERNS

dc.title

Marsileaceae sporocarps and spores from the late cretaceous of Georgia, U.S.A.

dc.type

Journal article

duke.contributor.orcid

Pryer, KM|0000-0002-9776-6736

pubs.begin-page

975

pubs.end-page

988

pubs.issue

6

pubs.organisational-group

Trinity College of Arts & Sciences

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Biology

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Duke Science & Society

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Duke

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Initiatives

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Institutes and Provost's Academic Units

pubs.publication-status

Published

pubs.volume

161

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