The Importance of Morphological Characterization of Recient Pollen Grains for the Comparative Study in Fossil Pollen Grains and their Implications in Ephedra L. (Gnetales).

MOGLIA M.; GOMEZ, MARIA ANGELICA; ARCUCCI A. ; DAGUERRE A

Mendoza

Encuentro; XXXVII Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2019

Sociedad Anual de Biologia de Cuyo

Many authors agreed that the study of recent pollen grains contribute to the taxonomy of some vegetal groups. By other side the comparative studies with fossil pollen grains had allowed to reconstruct paleoflora and paleoclimates. The primary objective of this work was to analyze pollen grains of recent South American species of Ephedra and compare them with fossil pollen grains recovered from La Cantera Formation in San Luis province (Early Cretaceous) that were assigned previously to this group .The pollen grains were removed of specimens deposited in a herbarium and stained with basic fuchsin. A minimum of 20 pollen grains were studied per sample, measured using a light binocular microscopy (1000 x) and were compared with the fossil palynomorphs. Fossil palynological samples used are located in the paleopalynological collection from IANIGLA CCT from Mendoza. The analysis showed that both morphological and morphometric characters of the grains are uniform in each of the recent species and do not correspond to individual differences. The main shared characters between species were: ellipsoidal to fusiform shape and polyplicate sculpture. These results support the previous idea that the great diversity in morphology and size of pollen grains assigned to Ephedra and recorded in La Cantera Formation indicate the presence of several species or even several genera in this association. This example shows a case where the study of recent species gives an important support to infer the diversity of species that lived in the past.