%0 Journal Article
%A Diéguez, Carmen
%A Rodríguez López, Juan Pedro
%A Meléndez Hevia, María Nieves
%T Marchantiopsid colonization mats from the Upper Aptian–Lower Albian of the Escucha Formation (Oliete Sub-Basin, Iberian Ranges, eastern Spain)
%D 2007
%@ 1631-0683
%U https://hdl.handle.net/20.500.14352/87945
%X In the Oliete Sub-Basin, the Escucha Formation has been divided into three different lithologic intervals, from base to top:E1 (heterolithic with coal), E2 (mainly sandstones), and E3 (claystones). At the upper part of the interval E2, a grey-siltylithosome has been recognized, corresponding to a low-energy sedimentary environment related to a sandy shoal. In this lithosome,marchantiopsid-rich beds extending up to tens of square metres have been preserved. The plant association consists ofwell-developed mature gametophytes of complex thallose liverworts with thalli radial, dichotomous branched, rosette forming,prostrate and, in most cases, with gemmae cups located on their dorsal surface. The occurrence of scattered individuals formingdistinct rosettes that, in many cases, are interlocked or interwoven and the loose arrangement of the association, alongwith sedimentological characteristics, allows us to interpret these liverworts-rich beds as monospecific colonization mats atearly stages of colonization, in which marchantiopsids played the role of pioneers. In addition, the high proportion of gemmiferousindividuals provides significant information on the environmental conditions and the effectiveness of colonization byasexual diaspores. Specimens have been assigned to family Marchantiaceae owing to their morphological features. Althoughliverworts colonization mats have been mentioned from the Albian of Antarctica, no fossil record of these existed at lowerpalaeolatitudes or in the Upper Aptian–Lower Albian. In addition, no previous record of clonal communities of plants derivedfrom gemmae exists. Due to the latter, the occurrence of the studied colonization mats becomes of prime importance
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