CONICET | Buscador de Institutos y Recursos Humanos

The Oligocene-Miocene interval is considered as one of the most important times in the early evolution of the sunflower family. Worldwide fossil records of Asteraceae indicate that Mutisiinae (Mutisieae) is the oldest tribe recorded so far (Africa, Australia, New Zealand, South America). In this contribution we present a chronological scheme of fossil Asteracean records from Patagonia, based on previous reports of Mutisiinae and Gochnatiinae subtribes and a new record of pollen type comparable to those of Cardueae. Four pollen types were identified on the basis of their exine features (sculpture, structure, and thickness). Morphotype 1 -Mutisiapollis sp.- (Late Oligocene), have spines with swollen bases, internal cavities and endosexine three times thicker than ectosexine; it appears to be closely allied to Serratula type (Cardueae) and, to Gongylolepis type (Mutisiinae from the Guayana group). Morphotype 2 -Mutisiapollis viteauensis (Barreda) Barreda- (latest Oligocene-Early Miocene), characterized by having microspines, with microperforated tectum, ecto- and endosexine equally thickened. This morphotype is close to Cnicothamnus type (Gochnatiinae). Morphotype 3 -Mutisiapollis sp.- (Late Miocene), with conspicuous microspines, comparable to Quelchia type (Gochnatiinae from the Guyana Group). Morphotype 4 Mutisiapollis patersonii Macphail and Hill- (Late Miocene), with miscrospines hardly distinguishable and exine very thickened at the equatorial level; it is close to some species of Chaetanthera and Mutisia (Mutisiinae). Some of extant members of Mutisieae (the Guayana group) are palynologically linked. The nearest living relatives of the fossil morphotypes here presented are no longer recorded in southeastern Patagonia. Most of them occur in northern South America (Guyana) or in the high altitudes of the Andes.