Phylogenetic and Palaeoecological studies on Cretaceous Monocotyledon angiosperms from NorthGondwana (Brazil and Egypt )
Evolution and Systematics of Plants and Fungi
Final Report Abstract
Monocots as one of the two main group of flowering plants are major elements of some ecosystems (grass and palms) as well as major food source for humans (cereales). They are represented by a huge diversity of life from ranging from the tiny duckweeds to the majestic palms. Despite their importance, their origin and early evolution remains unclear. According to molecular studies they must have diverged about 120 millions years ago in the Early Cretaceous but they become frequent in the fossil record only 40 millions years later in the Late Cretaceous.However, most of the studied fossil flora come from the northern mid-latitudes and the low latitude fossil record remained nearly unexplored. In this project, we studied monocots from the fossil plant collection from Northeastern Africa and Northeastern Brazil housed at the Natural History Museum of Berlin. This material was collected in the 70th to 90th but nerver thorougly studied. These collection proved to contain several new fossil monocot taxa, including the oldest Aroid (Calla family) preserved as a whole plant and coming from 115 million years old sediments from Northeaster Brazil. A 80 million years old flora from Northeastern Africa delivered a surprisingly rich monocot assemblage containing 9 taxa, which nearly equals the total number of fossil monocots known for that time worldwide. This assemblage contain several aquatics allied to the duckweed but also terrestrial monocots with affinites to classica inhabitant ot tropical rainforests such as Philodendron, Taro and Ginger. Their determination was difficult due to the lack of a clear terminology for leaf venation description (the fossils are mostly leaves) and necessitated the comparison with more than 150 herbarium specimens in order to conduce a phylogenetic analysis. Due to the affinities of these monocots with modern rainforest plants, we made preliminary climate estimates that point to high rainfall in Northeastern 80 millions years ago suggesting the presence of one of the first modern tropical rainforest.
Publications
- (2014). Hexagyne philippiana gen. et sp. nov., a piperalean angiosperm from the Early Cretaceous of northern Gondwana (Crato Formation, Brazil). Taxon, 63(6), 1275-1286
Coiffard, C., Mohr, B. A., & Bernardes-de-Oliveira, M. E.
(See online at https://doi.org/10.12705/636.17) - (2015). Lejalia sagenopteroides gen. nov. et comb. nov.: A new tropical member of Araceae from Late Cretaceous strata of northern Gondwana (Jebel Abyad, Sudan). Taxon, 64(5), 987-997
Coiffard, C., & Mohr, B. A.
(See online at https://doi.org/10.12705/645.8) - (2015). Montsechia, an ancient aquatic angiosperm. Proceedings of the National Academy of Sciences, 112(35), 10985-10988
Gomez, B., Daviero-Gomez, V., Coiffard, C., Martín-Closas, C., & Dilcher, D. L.
(See online at https://doi.org/10.1073/pnas.1509241112) - (2016). Afrocasia kahlertiana gen. et sp. nov., a new tropical member of Araceae from Late Cretaceous strata of northern Gondwana (Baris, Egypt). Taxon, 65(6), 1374-1384
Coiffard, C., & Mohr, B. A.
(See online at https://doi.org/10.12705/656.9)
