Metzgar, Jordan , Ickert-Bond, Stefanie .
From eastern Asia to North America: historical biogeography of the parsley ferns (Cryptogramma).
We examined the biogeographic history of the circumboreal parsley ferns (Cryptogramma) and calculated the ages of key nodes within the cryptogrammoid clade to better understand the climatic and geological settings for its diversification in Western North America. The broadly distributed cryptogrammoid clade (Llavea-Coniogramme-Cryptogramma) is basal within Pteridaceae. Llavea is known only from central America, Coniogramme is distributed mainly in eastern Asia, and most Cryptogramma species have boreal distributions, with a single disjunct taxon restricted to southern South America. This study builds upon previous research on the phylogenetic history and polyploidization events within the cryptogrammoid ferns. Utilizing a six locus plastid data set representing eight Cryptogramma species and 32 accessions from throughout the distributional range, six outgroup taxa and a relaxed-clock model with two secondary constraints, ancestral ranges were inferred using both likelihood (Lagrange) and Bayesian (BayArea) methods. The obtained chronogram and ancestral area reconstruction support an east Asian origin for the cryptogrammoid ferns and for crown group Cryptogramma in the mid-Oligocene. Most speciation events in crown group Cryptogramma occurred in the Pliocene after a subsequent dispersal to western North America. The youngest stem age estimate for the Beringian allotetraploid taxon C. sitchensis is inferred in the Pleistocene at 0.2 Ma. The only South American species, C. fumariifolia, results from a single long-distance dispersal event from east Asia. We also test the hypothesis that climate fluctuations at the onset of the Pleistocene spurred simultaneous divergence and dispersal events in section Cryptogramma. Well-established phylogenetic relationships and a reliance on boreal habitats and ranges with strong glacial influence make Cryptogramma an excellent test case for examining the impact of glaciation on range shifts and diversification.
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1 - University Of Alaska Fairbanks, Museum Of The North, 907 Yukon Drive, Fairbanks, AK, 99775, USA
2 - University Of Alaska Museum Of The North, Herbarium (ALA) And Dept. Of Biology And Wildlife, University Of Alaska Fairbanks, 907 Yukon Dr., Fairbanks, AK, 99775, USA
divergence time estimation.
Presentation Type: Oral Paper:Papers for Sections
Location: Pines North/Boise Centre
Date: Monday, July 28th, 2014
Time: 2:00 PM
Candidate for Awards:Edgar T. Wherry award