Early Cretaceous palm pollen tetrads from Patagonia, Argentina

LEANDRO C.A. MARTÍNEZ ; ARCHANGELSKY, A.; MERCEDES B. PRÁMPARO; SERGIO ARCHANGELSKY

CRETACEOUS RESEARCH (PRINT)

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2016 vol. 59 p. 129 - 139

0195-6671

Pollen tetrads and monads of spiny pollen grains with close affinities to palms have been found in severallocalities from the Lower Cretaceous (Barremian-Albian) of the Austral Basin (Magallanes), Patagonia(Argentina). When found dispersed, spiny and zonasulcate pollen grains, are commonly referred to thefossil genus Spinizonocolpites Muller, with close affinities to the extant palm Nypa. The Patagonianspecimens were compared with fossil and extant members of the Arecaceae, showing close similaritiesin shape and sculpture with the primitive members of the subfamily Calamoideae. Nypa producestetragonal tetrads different from the tetrahedral tetrads of the Spinizonocolpites-type recovered fromPatagonia. The specimens were studied with LM and SEM. The polarity, aperture orientation and tetradtype allow segregating the Patagonian grains from the Nypoideae and relating it to the Calamoideaesubfamily. These records suggest an antique origin of monocots and a probably initial diversification ofcalamoid palms during the Early Cretaceous in high latitudes of Gondwana. The presence of palmaeduring the Early Cretaceous in southern South America suggests a warm and humid climate, similar tothat found in present days at tropics.