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Abstract Detail

The rise and fall of photosynthate: Evolution of plant/fungus interactions from paleobotanical and phylogenomic perspectives

Selosse, Marc-André [1].

Evolution of the plant-fungal symbioses: questions for palaeontology.

We often look for the oldest fossil evidence of plant-fungal symbioses, in order to calibrate molecular clocks and to understand the evolution of plant-fungal interactions. Yet, such a useful research is limited by two major issues: (1) the need for good mycologists and biologists focusing on biological interactions to have a look at fossil data; and (2) the risk that uniformitarianism (the assumption that the same natural laws and processes that operate in the universe now have always operated in the universe in the past) is not always relevant. Considering the second point, zoologists are now well aware that, due to decimation of species and clades in the evolution, some fossil organisms cannot be attributed to any extant taxa – enigmatic Burgess Shale fossils well illustrate this idea. This paper concentrate on several enigmatic plant-fungal interactions in the fossil record, often interpreted in the light of extant organisms: while some of these interactions can be interpreted based on modern equivalent symbioses (such as the Devonian lichens Winfrenatia reticulata, Cyanolichenomycites devonicus and Chlorolichenomycites salopensis), some are less clear in nature and partners, such as the Nematophytes (Prototaxites) and Spongiophyton. Whether the later associations belong to fully extinct lineages, without extent relatives, or can be considered as ancestral to extant living forms, remains a difficult question. It also raises concerns that some fossil associations that look superficially similar to extant ones may indeed result from a convergence between independent lineages, respectively extinct and extant. Here, we come back to the need for good mycologists and interaction biologists to look at fossils. Finally, a caveat will also be emphasized: there is no 'living fossils'. This concept only reflects a stasis for some, but not necessarily all, morphological traits, and evolution always proceeds in all lineages. Especially, it can be misleading to consider that early-branching lineages (such as Marchantiophyta for mycorrhizal interaction) are 'necessarily' or 'without more careful investigation' current equivalent of extinct, ancestral living forms.

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1 - Museum National d'Histoire Naturelle, Institut de Systématique et d'Evolution de la Biodiversite, CP50 - 45 rue Buffon , Paris, 75005, France

Living fossils
Fungal fossils.

Presentation Type: Symposium Presentation
Session: SY12
Location: Hall A/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 3:45 PM
Number: SY12006
Abstract ID:475
Candidate for Awards:None

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