Corystospermaceae Temporal range:
| |
---|---|
![]() | |
Umkomasia macleanii reconstructed plant, Late Triassic, Molteno Formation, Umkomaas, South Africa.[1] | |
Scientific classification ![]() | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Division: | †Pteridospermatophyta |
Order: | †Corystospermales |
Family: | †Corystospermaceae Thomas 1933 |
Genera | |
|
Corystospermaceae is a natural family of seed ferns (Pteridospermatophyta) also called Umkomasiaceae, and first based on fossils collected by Hamshaw Thomas from the Burnera Waterfall locality near the Umkomaas River of South Africa.[2] Corystosperms are typified by a group of plants that bore Dicroidium leaves, Umkomasia ovulate structures and Pteruchus pollen organs, that were widespread over Gondwana during the Triassic period. Other fossil Mesozoic seed plants with similar reproductive structures have also sometimes been included within the concept, such as the "doyleoids" from the Early Cretaceous of North America and Asia.[3] A potential corystosperm, the leaf fossil Komlopteris cenozoicus, is known from the Eocene of Tasmania, at least 13 million years after the Cretaceous–Paleogene extinction event.[4]
Description
Umkomasiaceae have helmet-like cupules around ovules born in complex large branching structures (Umkomasia). The pollen organ (Pteruchus) has numerous cigar-shaped pollen sacs hanging from epaulette-like blades, again in complex branching structures.
The leaves (Dicroidium) are tied to the fertile organs by similarities of cuticular structure, because their cuticles were robust like those of gymnosperms and unlike the thin leaves of ferns.
See also
References
- ^ Retallack, G.J.; Dilcher, D.L. (1988). "Reconstructions of selected seed ferns". Missouri Botanical Garden Annals. 75 (3): 1010–1057. doi:10.2307/2399379. JSTOR 2399379.
- ^ Thomas, H.H. (1933). "On some pteridospermous plants from the Mesozoic rocks of South Africa". Philosophical Transactions of the Royal Society B. 222 (483–493): 193–265. doi:10.1098/rstb.1932.0016.
- ^ Shi, Gongle; Herrera, Fabiany; Herendeen, Patrick S.; Clark, Elizabeth G.; Crane, Peter R. (2022-12-31). "Silicified cupulate seed-bearing structures from the Early Cretaceous of eastern Inner Mongolia, China: rethinking the corystosperm concept". Journal of Systematic Palaeontology. 20 (1): 1–33. doi:10.1080/14772019.2022.2133644. ISSN 1477-2019. S2CID 253562726.
- ^ McLoughlin, Stephen; Carpenter, Raymond J.; Jordan, Gregory J.; Hill, Robert S. (2008). "Seed ferns survived the end-Cretaceous mass extinction in Tasmania". American Journal of Botany. 95 (4): 465–471. doi:10.3732/ajb.95.4.465. ISSN 1537-2197. PMID 21632371.
External links
- "Fossilworks: Lepidopteris". paleodb.org. Retrieved 2016-03-18.