Hydropteris

Hydropteris
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Division: Polypodiophyta
Class: Polypodiopsida
Order: Salviniales
Family: †Hydropteridaceae
Genus: †Hydropteris
Rothwell & Stockey
Species:
†H. pinnata
Binomial name
†Hydropteris pinnata
Rothwell & Stockey

Hydropteris is an extinct genus of heterosporous pteridophytes in the order Salviniales. The genus comprises a single species, Hydropteris pinnata. Fossils of the genus were found in southern Alberta, Canada in the St. Mary River Formation, which corresponds to the Upper Cretaceous, Maastrichtian.

Description

This fern shares many features with other members of the Salviniales. Hydropteris possesses sporocarps like those in Marsileaceae, but megaspore complexes like those in Salviniaceae (assignable to the sporae dispersae genus Parazolla Hall.), and has leaves like non-heterosporous ferns. This combination of traits has made the phylogenetic placement of Hydropteris within Salviniales difficult to establish. Two hypotheses have been proposed. The first is of Hydropteris as sister to Salvinia and Azolla and the second is of Hydropteris as the earliest diverging member of the heterosporous water ferns.

References

  1. 1 2 3 4 Rothwell, Gar W.; Stockey, Ruth A. (1994). "The role of Hydropteris pinnata gen. et sp. nov. in reconstructing the cladistics of heterosporous ferns". American Journal of Botany. 81 (4): 479–492. doi:10.1002/j.1537-2197.1994.tb15473.x. ISSN 1537-2197.
  2. ↑ Pryer, Kathleen M. (1999). "Phylogeny of Marsileaceous Ferns and Relationships of the Fossil Hydropteris pinnata Reconsidered". International Journal of Plant Sciences. 160 (5): 931–954. doi:10.1086/314177. ISSN 1058-5893.
  3. ↑ Yamada, Toshihiro; Kato, Masahiro (2002). "Regnellites nagashimae gen. et sp. nov., the Oldest Macrofossil of Marsileaceae, from the Upper Jurassic to Lower Cretaceous of Western Japan". International Journal of Plant Sciences. 163 (5): 715–723. doi:10.1086/342036. ISSN 1058-5893.