Occurrence of the genus Galeacornea (elaterate pollen) at the Cretaceous of central-western Argentina

NARVÁEZ PAULA LILIANA; PRÁMPARO MERCEDES; MEGO NATALIA

Salvador

Congreso; XIV International Palynological Congress - X International Organisation of Palaeobotany Conference; 2016

IFPS ? International Federation of Palynological Societies, IOS ? International Organisation of Palaeobotany and ALPP ? Asociación Latinoamericana de Palaeobotánica y Palinología

Elater-bearingtaxa are characteristic of the Albian-Cenomanian Elaterate Province correspondingto northern South America, Central and North Africa and the Arabian Peninsula.Species of the elaterate complex occur in high abundances and diversity only inthe circum-Atlantic basins. A new elaterate species named Galeacornea guayaguensis Prámparo, Narváez and Mego, has beenrecently described from sediments of the Lagarcito Formation (San Luis Basin)at the ?La Yesera Sur? section, Sierra de Guayaguás ranges, San Juan Province,central-western Argentina.The psamopelitic-evaporitic sequence with gypsum and anhydrite intercalationsyields a rich palynoflora of continental origin (fluvio-lacustrine). G. guayaguensis shares with other Galeacorneaspecies the shape of the grain, the presence of an annular rim and the distalappendages. The ridge-like appendages are similar to those of G. stoveri and G. tarimensis, although they never fuse with the annular rim orwith each other at their ends as it respectively occursin other species. The new species from Argentina provides further evidence onthe morphological variation of elaterate grains and extends the geographicaldistribution of the genus Galeacorneato South America midlatitudes, far beyond the palaeophytogeographicAlbian?Cenomanian Elaterates Province of the equatorial region.  However, it is important to note, that elaterates inArgentina are less diverse and abundant than at lower latitudes. Severalstudies suggest that elaterates and polyplicate pollen are botanically related. At the Lagarcito Formation Galeacornea guayaguensis was found within an association dominated bygymnospermous elements, mainly represented by polyplicate (diverse and abundantEphedripites, Gnetaceaepollenites, Steevesipollenites)and rimulate grains (Classopollis). AnAptian-Albian range was estimated for the palynologic association recovered inthe studied area, based on the occurrence and biostratigraphical value ofdifferent verrucate spores. It is remarkable the presence of Reyrea polymorphus Herngreen, a significant marker taxon from the early?middle Albian of Brazil,associated with the new elaterate species in central-western Argentina