Eobowenia gen. nov. from the Early Cretaceous of Patagonia: indication for an early divergence of Bowenia?

Abstract

BackgroundEven if they are considered the quintessential “living fossils”, the fossil record of the extant genera of the Cycadales is quite poor, and only extends as far back as the Cenozoic. This lack of data represents a huge hindrance for the reconstruction of the recent history of this important group. Among extant genera, Bowenia (or cuticles resembling those of extant Bowenia) has been recorded in sediments from the Late Cretaceous and the Eocene of Australia, but its phylogenetic placement and the inference from molecular dating still imply a long ghost lineage for this genus.ResultsWe re-examine the fossil foliage Almargemia incrassata from the Lower Cretaceous Anfiteatro de Ticó Formation in Patagonia, Argentina, in the light of a comparative cuticular analysis of extant Zamiaceae. We identify important differences with the other member of the genus, viz. A. dentata, and bring to light some interesting characters shared exclusively between A. incrassata and extant Bowenia. We interpret our results to necessitate the erection of the new genus Eobowenia to accommodate the fossil leaf earlier assigned as Almargemia incrassata. We then perfom phylogenetic analyses, including the first combined morphological and molecular analysis of the Cycadales, that indicate that the newly erected genus could be related to extant Bowenia.Conclusion Eobowenia incrassata could represent an important clue for the understanding of evolution and biogeography of the extant genus Bowenia, as the presence of Eobowenia in Patagonia is yet another piece of the biogeographic puzzle that links southern South America with Australasia.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-017-0943-x) contains supplementary material, which is available to authorized users.

Three‐dimensional digital image construction of metaxylem vessels in root tips of Zea mays subsp. mexicana from thin transverse sections

“…embryo and tissues (Bougourd et al., ; Truernit et al., ; Wuyts et al., ), as well as Zea L., Pisum L., Nicotiana L., Medicago L. (Warner et al., ), and Bowenia Hook. (Coiro and Pott, ). However, clearing agents such as chloral hydrate, fluorescent stains such as Calcofluor White MR2, and tagged antibody probes require a long time (5 d) to penetrate the plant tissue (Warner et al., ).…”

Pinnule and Stomatal Size and Stomatal Density of Living and Fossil Bowenia and Eobowenia Specimens Give Insight into Physiology during Cretaceous and Eocene Paleoclimates

“…The Anfiteatro de Ticó Formation is located in Patagonia, Argentina (Coiro and Pott 2017). At the time of fossil deposition, the Aptian, the site was at an extremely high southern latitude of more than 607S (Archangelsky and Archangelsky 2013).…”

“…The final site containing Bowenia not formally described is Maslin Bay (McGowran et al 1970). Eobowenia has been included because it is a sister group to Bowenia, and the two genera have a Gondwanan distribution (Coiro and Pott 2017). The general morphology of the fossils and their identification is found in Hill (1978), Coiro and Pott (2017), and Hill et al (2018).…”

“…nov. from the Aptian of Argentina (Coiro and Pott 2017) is included in the analysis, since it is regarded as the nearest fossil relative of Bowenia. Hill (1978) described two macrofossil species of Bowenia, based on pinnule remains, from Eocene sediments in southeastern Australia, and recently Hill et al (2018) reviewed the macrofossil record of Bowenia and described a new Early Eocene species from Tasmania.…”

New Macrofossils of the Australian Cycad Bowenia and Their Significance in Reconstructing the Past Morphological Range of the Genus

“…1058-5893/2019/18002-0002$15.00 DOI: 10.1086/701103 by these fossil species when they were alive. The recent description of Aptian fossils from Argentina assigned to Eobowenia (Coiro and Pott 2017) is also considered, since it is probably the most closely related fossil taxon to Bowenia.…”