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A new well-preserved spore assemblage has been discovered from the Lower Devonian Nogueras Formation of Mezquita de Loscos (Teruel Province, north-eastern Spain). The palynoflora includes 34 spore species belonging to 20 genera, among which 14 are new for the locality, e.g.Apiculiretusispora,Brochotriletes,Cirratriradites,Iberoespora,KnoxisporitesandVerrucosisporites. The assemblage is mainly composed of trilete spores, while tripapillate and monolete forms are also observed. An early Pragian age is suggested for the fossil site. Specimens ofLatosporites ovalis, a species previously well-documented only from the late Pragian–Emsian of Saudi Arabia and Brazil, are found in this assemblage and represent to date the earliest known occurrence of this species. Besides the description of the palynoflora, we also provide here a synthesis of the plant-bearing localities of the study area. [ABSTRACT FROM PUBLISHER]

Mass extinctions are crucial to understanding changes in biodiversity through time. However, it is still disputed whether extinction dynamics in the marine and terrestrial biotas followed comparable trajectories. For instance, while marine realms have suffered five strong depletions in diversity, the so-called ‘Big Five’ mass extinctions, only the end-Permian event appears to have also resulted in a major abrupt reduction in continental diversity. However, recent evidence based on the diversity dynamics of vegetation has suggested the presence of two major episodes of extinction in the terrestrial environments, at the end-Carboniferous and the end-Permian times. This apparent contradiction is addressed in the present study. Here, we show that while the end-Carboniferous plant extinction was focused on particular environments (e.g. tropical wetlands) and affected mainly the free-sporing plant diversity (i.e. lycopsids, ferns and progymnosperms), only the end-Permian mass extinction had devastating effects on vegetation on a global scale. If we take the biosphere as a whole, the results highlight that the end-Permian biotic crisis was the only genuine global mass extinction event, affecting widely both the marine and terrestrial environments. [ABSTRACT FROM PUBLISHER]

The multiovulate cupule of a new spermatophyte,Thorezia vezerensisgen.etsp. nov., is described from the Late Devonian aged sediments from Trooz Quarry in Belgium. In gross morphology, it conforms to theMoresnetiamorphotype and has a cupule that is composed of four independent quarters that each dichotomises three times. Each cupule quarter contains one single ovoid preovule with a long pedicel and an integument that has small apical teeth surrounding a rudimentary micropyle. Morphological variability in the materials examined is interpreted as being related to preovule maturity, and from this a good understanding of the ontogenetic development from preceding dispersal has been developed. Up to now, 17 spermatophyte species have been described, 11 of which come from eastern Laurussia. This diversity in eastern Laurussia contrasts strongly with the low diversity characterizing contemporaneous floras from other phytogeographical areas. We suggest here that the arid climatic conditions prevailing in eastern Laurussia favoured the development of diverse spermatophyte communities and contributed to reduced diversity and abundance of contemporaneous free-sporing plant diversity. [ABSTRACT FROM AUTHOR]