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Papuacedrus (Cupressaceae) in Eocene Patagonia: A new fossil link to Australasian rainforests
Author(s) -
Wilf Peter,
Little Stefan A.,
Iglesias Ari,
Carmen Zamaloa María,
Gandolfo María A.,
Cúneo N. Rubén,
Johnson Kirk R.
Publication year - 2009
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.3732/ajb.0900085
Subject(s) - rainforest , temperate rainforest , biology , ecology , biome , subtropics , cupressaceae , cloud forest , montane ecology , ecosystem , pollen
The 51.9 Ma Laguna del Hunco (LH) and 47.5 Ma Río Pichileufú (RP) floras from Patagonia, Argentina are unusually rich, angiosperm‐dominated assemblages with living relatives in the low‐latitude West Pacific, neotropics, and temperate southern latitudes. The diverse gymnosperms in these floras are important for Gondwanan biogeographic history and paleoclimatic interpretations. “ Libocedrus ” prechilensis Berry 1938 (Cupressaceae), previously known only from the holotype (RP), a vegetative branch, is revised here based on new material from both localities, including a seed cone attached to a shoot with cuticle (LH). Characters of these fossils are diagnostic of monotypic Papuacedrus (highlands of New Guinea and Moluccas). Living P. papuana is most abundant in cloud forests receiving up to 4 m rainfall annually, whereas Austrocedrus ( Libocedrus ) chilensis , the basis of comparison when the fossil species was named, inhabits dry, cold steppe margins to mediterranean climates in southern South America. We establish Papuacedrus prechilensis comb. nov., which simultaneously invalidates a southern South American connection for the fossil floras and reveals a link to West Pacific montane rainforests. Combined evidence indicates a biome similar to extant subtropical, or tropical montane, rainforests that persisted for at least 4.4 Myr, linking elevated floral richness to abundant rainfall.