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Deserts are stressful environments where the living beings must acquire different strategies to survive due to the water stress conditions. From the late Albian to the early Cenomanian, the northern and eastern parts of Iberia were the location of the desert system represented by deposits assigned to the Utrillas Group, which bear abundant amber with numerous bioinclusions, including diverse arthropods and vertebrate remains. In the Maestrazgo Basin (E Spain), the late Albian to early Cenomanian sedimentary succession represents the most distal part of the desert system (fore-erg) that was characterised by an alternation of aeolian and shallow marine sedimentary environments in the proximity of the Western Tethys palaeo-coast, with rare to frequent dinoflagellate cysts. The terrestrial ecosystems from this area were biodiverse, and comprised plant communities whose fossils are associated with sedimentological indicators of aridity. The palynoflora dominated by wind-transported conifer pollen is interpreted to reflect various types of xerophytic woodlands from the hinterlands and the coastal settings. Therefore, fern and angiosperm communities abundantly grew in wet interdunes and coastal wetlands (temporary to semi-permanent freshwater/salt marshes and water bodies). In addition, the occurrence of low-diversity megafloral assemblages reflects the existence of coastal salt-influenced settings. The palaeobotanical study carried out in this paper which is an integrative work on palynology and palaeobotany, does not only allow the reconstruction of the vegetation that developed in the mid-Cretaceous fore-erg from the eastern Iberia, in addition, provides new biostratigraphic and palaeogeographic data considering the context of angiosperm radiation as well as the biota inferred in the amber-bearing outcrops of San Just, Arroyo de la Pascueta and La Hoya (within Cortes de Arenoso succesion). Importantly, the studied assemblages include Afropollis, Dichastopollenites, Cretacaeiporites together with pollen produced by Ephedraceae (known for its tolerance to arid conditions). The presence of these pollen grains, typical for northern Gondwana, associates the Iberian ecosystems with those characterising the mentioned region. [ABSTRACT FROM AUTHOR]

The fossil plant Montsechia vidalii is well known from the Barremian of Spain and was identified as an early angiosperm. It is interpreted as an aquatic plant that thrived in freshwater wetlands, with very limited or no connection with the marine realm, and under a seasonal semi-arid tropical climate. This research paper reports the youngest known occurrence of the genus Montsechia , in upper Albian amber-bearing strata from the Maestrazgo Basin (NE Spain), demonstrating the broad adaptation and evolutionary stability of the genus during the Early Cretaceous. The studied upper Albian material is identified as M. aff. vidalii since it differs from the Barremian Montsechia vidalii in having a medium-thick cuticle and paracytic stomata on the abaxial leaf cuticle. In addition, associated seeds, fruit and pollen grains have been found. The fruit is indehiscent and ascidiate in shape with a single seed inside. The seeds are orthotropous and have been identified as Spermatites sp. The pollen grains were found adhering to a sterile twig. They are monocolpate and assigned to Transitoripollis sp., reinforcing the early angiosperm hypothesis. Unlike its Barremian relative, the late Albian M. aff. vidalii developed under predominantly arid conditions in a fore-erg setting characterised by an interaction of aeolian dune and tide-dominated coastal deposits that reflected general eustatic rise conditions of the mid-Cretaceous. In this regard, the studied remains were found as a minor component of a supratidal coastal plant association largely dominated by conifers of the genera Frenelopsis and Dammarites. • Montsechia cf. vidalii from upper Albian strata of the Maestrazgo Basin, Spain. • Mid-Cretaceous supratidal plant communities of the Western Tethys coast. • Early angiosperm expansion into coastal environments during the mid-Cretaceous. [ABSTRACT FROM AUTHOR]