The Oligocene fossil caudates of Oregon: Classification, analysis, and insights on the paleoecology and conservation biology of Pacific newts

Abstract

Newts, abundant worldwide, have unclear pre-Pliocene evolution and phylogenetic relationships. North America has a sporadic pre-Pliocene newt record. Several undescribed fossils can address this lack of information. I built a character matrix of >70 morphological characters for extant newts and two fossil species, Taricha oligocenica and Taricha lindoei. Phylogenetic analyses were used to investigate the relationships of the fossil taxa within newts. The morphology of the fossil taxa was compared with extant North American newts to redescribe the fossil specimens. The past ecology and biogeography of North American fossil newts was compared with their current ecologies and distribution to better understand their evolution and dispersal and to predict possible changes for newts in the face of environmental change. Results indicate that T. oligocenica and T. lindoei are closely-related species nested within Taricha, but their relationships with extant species are unresolved; the genus itself is rooted at least 32 Ma.