Macrofossil floras of the Latady Basin, Antarctic Peninsula

New collections of plant material from the Merrick and Sweeney Mountains provide further evidence of Jurassic floral diversity in the Antarctic Peninsula. Eighteen taxa are recognised, including sphenophytes (Equisetum), ferns (Cladophlebis, Sphenopteris, Coniopteris), Bennettitales (Otozamites, Zamites, Ptilophyllum, Dicytozamites, Williamsonia), conifers (Pagiophyllum, Brachyphyllum, Elatocladus), and other seed plants (Taeniopteris, Archangelskya, Pachypteris). Many of these species occur in floras from the Botany Bay Group (Early–Middle Jurassic), and other Late Jurassic to Early Cretaceous sites across the Antarctic Peninsula. The plant material from the Latady Basin occurs in two main associations with distinct floristic compositions that reflect local environmental and taphonomic conditions. The richest localities occur in the deltaic settings, where paleosoil and leaf litter layers are preserved. In contrast, relatively little plant material is found in the wholly marine units such as those from the Hauberg Mountains

A short history of MADS-box genes in plants

Evolutionary developmental genetics (evodevotics) is a novel scientific endeavor which assumes that changes in developmental control genes are a major aspect of evolutionary changes in morphology. Understanding the phylogeny of developmental control genes may thus help us to understand the evolution of plant and animal form. The principles of evodevotics are exemplified by outlining the role of MADS-box genes in the evolution of plant reproductive structures. In extant eudicotyledonous flowering plants, MADS-box genes act as homeotic selector genes determining floral organ identity and as floral meristem identity genes. By reviewing current knowledge about MADS-box genes in ferns, gymnosperms and different types of angiosperms, we demonstrate that the phylogeny of MADS-box genes was strongly correlated with the origin and evolution of plant reproductive structures such as ovules and flowers. It seems likely, therefore, that changes in MADS-box gene structure, expression and function have been a major cause for innovations in reproductive development during land plant evolution, such as seed, flower and fruit formation