TitleNew amber deposit provides evidence of Early Paleogene extinctions, paleoclimates, and past distributions
Publication TypeJournal Article
Year of Publication1999
AuthorsPoinar, GO, Archibald, B, Brown, A
JournalCanadian Entomologist
Volume131
Pagination171-177
Type of ArticleJournal Article
ISSN0008-347X
Abstract

A large, previously unstudied amber deposit in British Columbia dating from the Early to Middle Eocene (50-55 Ma) provides a noteworthy new source of terrestrial invertebrates and other life forms. This deposit contains what are likely the earliest unequivocal ants (members of the family Formicidae), including extinct representatives of Technomyrmex Mayr 1872, Leptothorax Mayr 1855, and Dolichoderus Lund 1831. Discovering Technomyrmex and a corydiinid cockroach, both of which are currently restricted to tropical regions, confirms earlier evidence of warm paleoclimates and past biogeographic distributions in the early Paleogene. Chemical analysis of the amber indicates that the source tree was an araucarian belonging to or near the genus Agathis Salisbury 1807, and demonstrates that this genus survived into the Tertiary in the Northern Hemisphere, since previous records revealed Agathis as a component only of the Cretaceous forests in North America. Comparing the Hat Creek fossil assemblages in this deposit with those from the well-studied western Canadian Late Cretaceous amber deposits offers a unique opportunity to study extinction and speciation events on both sides of the Cretaceous-Tertiary boundary.

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