Biodiversity of ecosystems in an arid setting: The late Albian plant communities and associated biota from eastern Iberia

and 7Q), constituting 80% of the total palynomorph sum at some levels. Other frequent gym- nosperms include Araucariacites australis, Exesipollenites tumulus (Fig 7P) and Monosulcites spp. Bisaccate grains (Fig 7R–7T) usually represent a minor component of the assemblages. Fern spores represented the most diversified group of miospores in all the studied sections and occasionally reached dominance, being Cyathidites australis and C. minor (Fig 8B) the most frequently occurring species. Angiosperms, mainly represented by the genera Clavatipollenites (Fig 9C) and Retimonocolpites (Fig 9K), were recorded in significant numbers at specific levels from the CA and AP sections. A low number of tricolpate grains were identified in the three successions (Fig 9P–9W). The PCA presents a variance of 33.8% in the first two dimensions (Fig 10). On the first axis (19.5% of variance), the taxa with negative coordinates were Classopollis spp., Exesipollenites tumulus, Araucariaceae, Patellasporites tavaredensis, Cicatricosisporites spp. and Crassipollis chaloneri. In contrast, Inaperturopollenites dubius, Eucommiidites troedsonii, Peromonolites allenensis, Monosulcites spp., Cyathidites/Deltoidospora, Gleicheniaceae, Clavatipollenites spp., Pennipollis spp., Tucanopollis spp. and the dinocysts presented positive coordinates in the PCA plot. The scattering of samples from AP and SJ along the first axis of the plot suggests the exis- tence of an ecological gradient defining two vegetation types at the extremes. The second axis

(14.3% of variance) discriminates spores in the negative extreme, from wind-transported gym- nosperm pollen grains plus marine protists, in the positive one. While samples from AP and Fig 10. Principal Component Analysis (PCA) performed with the most relevant identified taxa and levels. (A) Classopollis spp. (B) Exesipollenites tumulus. (C) Araucariaceae. (D) Patellasporites tavaredensis. (E) Cicatricosisporites spp. (F) Crassipollis chaloneri. (G) Clavatipollenites spp. (H) Plicifera spp. (I) Cyathidites/Deltoidospora. (J) Gleicheniidites senonicus. (K) Monosulcites spp. (L) Eucommiidites sp. (M) Pennipollis spp. (N) Peromonolites allenensis. (O) Tucanopollis spp. (P) Marine protists. (Q) Inaperturopollenites dubius. https://doi.org/10.1371/journal.pone.0282178.g010 PLOS ONE Late Albian desert biota from Iberia PLOS ONE | https://doi.org/10.1371/journal.pone.0282178 March 2, 2023 25 / 51