Diverse assemblages of dispersed spores have been recovered from Middle Devonian rocks in northern Spain, revealing a significant endemism in the flora. Middle Devonian Iberia was part of a relatively isolated island complex (Armorican Terrane Assemblage), separated by considerable tracts of ocean from Laurussia to the northwest and Gondwana to the southeast. The Middle Devonian deposits of the Cantabrian Zone of northern Spain are entirely marine and comprise a thick clastic unit sandwiched between extensive carbonate units. The clastic unit, the laterally equivalent Naranco, Huergas and Gustalapiedra formations of Asturias, León and Palencia Provinces, represents a nearshore-offshore transect across a marine shelf. This unit is also believed to encompass the Kačák Event, an important global extinction event. The recovered palynomorphs include marine (acritarchs, chitinozoans, scolecodonts) and terrestrial (spores) assemblages. These are abundant and well preserved, although of variable thermal maturity. Here, we describe the dispersed spores and consider their significance as regards biostratigraphy, palaeophytogeography and Kačák Event interpretation. The dispersed spores represent a single assemblage assignable to the lemurata-langii Assemblage Zone (lemurata Subzone) indicating a probable early (but not earliest) Givetian age. Signs of endemism include various taxa known only from this region, some taxa appearing to have discordant ranges compared with elsewhere, and the absence from Iberia of certain prominent taxa characteristic of coeval assemblages elsewhere, such as those with grapnel-tipped processes. The abrupt interruption of carbonate deposition, with a change to rapid deposition of thick clastic deposits, provides support for a monsoonal cause of the Kačák Event.

Askew, A. & Wellman, C. 2018 - Supplementary Chart S1 - Playa del TranqueruA StrataBugs chart of the palynology of the Playa del Tranqueru sectionAskew, A. & Wellman, C. 2018 - Supplementary Chart S2 - San Pedro de NoraA StrataBugs chart of the palynology of the San Pedro de Nora sectionAskew, A. & Wellman, C. 2018 - Supplementary Chart S3 - Crémenes-Las SalasA StrataBugs chart of the palynology of the Crémenes-Las Salas sectionAskew, A. & Wellman, C. 2018 - Supplementary Table S1 - Count dataCount data for every studied site. + denotes a species is present, but outside the 200 count; interpreted as rare.Askew, A. & Wellman, C. 2018 - Supplementary textGeology of investigated localities and sample details