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Geminispermum, an Early Cretaceous (early–middle Albian) cupulate unit from the angiosperm-dominated Puddledock flora of eastern North America
- Source :
- Friis, E M, Crane, P R & Pedersen, K R 2019, ' Geminispermum, an Early Cretaceous (early-middle Albian) cupulate unit from the angiosperm-dominated Puddledock flora of eastern North America ', Acta Palaeobotanica, vol. 59, no. 2, pp. 229-239 . https://doi.org/10.2478/acpa-2019-0020
- Publication Year :
- 2019
- Publisher :
- W. Szafer Institute of Botany Polish Academy of Sciences, 2019.
-
Abstract
- A new genus and species, Geminispermum virginiense, is described based on a well-preserved coalified cupulate reproductive unit recovered from the Early Cretaceous (early–middle Albian) Puddledock locality, Virginia, U.S.A. The reproductive unit is bisymmetrical and consists of an axis that bifurcates into two cupule-bearing stalks, each in the axil of a bract. Each cupule stalk bears a single non-valvate cupule recurved towards the center of the reproductive unit. The cupule opens distally by a short transverse slit with a distinct upper margin. Each cupule almost completely encloses a single orthotropous seed that is free from the cupule except at the base. The nucellus is also free from the integument except at the basal point of attachment. Geminispermum combines features of the ovulate structures of Caytoniales, Umkomasiales (= Corystospermales, including Doyleales) and Petriellales, but cannot be included in any of these existing orders as they are currently understood. The recurved, closed, non-valvate cupules are particularly similar to those of Caytonia, Petriellaea and Reymanownaea in external morphology, but differ in being one-seeded. The cupules of Geminispermum differ from the one-seeded cupules of Umkomasiales in being non-valvate and in having only a single cupule per bract. Geminispermum is perhaps most similar to the one- or two-seeded non-valvate cupules of Ktalenia from the Early Cretaceous of Argentina, but Ktalenia is poorly preserved, details of cupule architecture are uncertain, and the cupules appear to be associated with a single strongly dissected bract. Geminispermum is currently the only unequivocal seed plant cupule recovered from the Early Cretaceous Potomac Group and is distinct from all previously described cupulate reproductive structures.
- Subjects :
- 0106 biological sciences
Potomac Group
Corystospermales
010506 paleontology
Flora
Bract
Caytoniales
synchrotron radiation X-ray tomographic microscopy
biology
Doyleales
biology.organism_classification
010603 evolutionary biology
01 natural sciences
Cretaceous
The integument
Paleontology
Umkomasiales
Genus
seed ferns
General Earth and Planetary Sciences
Petriellales
General Agricultural and Biological Sciences
Ovule
0105 earth and related environmental sciences
Subjects
Details
- ISSN :
- 20820259
- Volume :
- 59
- Database :
- OpenAIRE
- Journal :
- Acta Palaeobotanica
- Accession number :
- edsair.doi.dedup.....6d802b0b50843d300958579074a15b7b