Cutting the long branches: Consilience as a path to unearth the evolutionary history of Gnetales

Abstract

The Gnetales are one of the most fascinating groups within seed plants. Although the advent of molecular phylogenetics has generated some confidence in their phylogenetic placement of Gnetales within seed plants, their macroevolutionary history still presents many unknowns. Here, we review the reasons for such unknowns, and we focus the discussion on the presence of “long branches” both in their molecular and morphological history. The increased rate of molecular evolution and genome instability as well as the numerous unique traits (both reproductive and vegetative) in the Gnetales have been obstacles to a better understanding of their evolution. Moreover, the fossil record of the Gnetales, though relatively rich, has not yet been properly reviewed and investigated using a phylogenetic framework. Despite these apparent blocks to progress we identify new avenues to enable us to move forward. We suggest that a consilience approach, involving different disciplines such as developmental genetics, paleobotany, molecular phylogenetics, and traditional anatomy and morphology might help to “break” these long branches, leading to a deeper understanding of this mysterious group of plants.

Embracing uncertainty: The way forward in plant fossil phylogenetics

“…The identification of nonrandom homoplasy could then allow us to revisit our primary homology hypotheses in the light of convergence of evidence, i.e., by looking at developmental, genetics, or other information on the genesis of those sets of characters (Bateman, 1994; Coiro et al, 2022). The process of revision of primary homology via convergence of evidence would help to make plant fossil phylogenetics a source of new hypotheses for the whole of plant biology and further solidify the role of paleobiological paleobotany as a multidisciplinary and intersectional discipline (Rothwell et al, 2014; Rothwell and Tomescu, 2018).…”

Past climates and plant migration – the significance of the fossil record

“…Understanding the past distribution and movement of plants and animals continues to fascinate many researchers. As a result of careful research on the relationships and distribution of both fossils and living taxa, we now know a great deal about general patterns of migration (Tarran et al ., 2016; Schoenenberger et al ., 2020; Coiro et al ., 2022; Herendeen et al ., 2022; Khan et al ., 2022). However, the more we discover, the more apparent it becomes that Earth's history is complex and there is still much to be revealed (Hill & Khan, 2022).…”

Parallel evolution of angiosperm‐like venation in Peltaspermales: a reinvestigation of Furcula

“…As a consequence of these benefits, meshed venation systems appear to have evolved independently and at multiple times throughout the history of euphyllophytes (Alvin & Chaloner, 1970; Trivett & Pigg, 1996; Boyce & Knoll, 2002; Boyce, 2005). Other than in angiosperms, reticulate venation occurs in a broad range of plant groups including Ophioglossales, Marattiales, Polypodiales (Wagner, 1979), Medullosales (Zodrow et al ., 2007), Glossopteridales (Pigg & McLoughlin, 1997), Peltaspermales (Krassilov, 1995), Bennettitales (Seward, 1903; Xu et al ., 2023), Cycadales (Erdei & Manchester, 2015; Erdei et al ., 2019; Coiro et al ., 2023), Ginkgoales (Arnott, 1959), Petriellales (Bomfleur et al ., 2014), Caytoniales (Halle, 1910), and Gnetales (Rydin et al ., 2003; Yang et al ., 2015; Coiro et al ., 2022). Instead, venation combining a hierarchical structure with anastomosing venation is much less common, being present in some ferns (Wagner, 1979), Gigantopteridales (Glasspool et al ., 2004), Gnetum L., and various seed plants of uncertain affinities (Cornet, 1993; Trivett & Pigg, 1996; Anderson & Anderson, 2003).…”