Abstract Detail

Pteridological Section/AFS

Schneider, Harald [5], Ranker, Tom A. [6], Russell, Stephen J. [7], Cranfill, Ray [1], Geiger, Jennifer M. O. [3], Aguraiuja, Ruth [4], Wood, Ken R. [2], Grundmann, Michael [7], Vogel, Johannes C. [7].

Origin of the endemic fern genus Diellia (Aspleniaceae) coincides with the renewal of Hawaiian terrestrial life in the early Miocene.

The enigmatic fern genus Diellia, endemic to the Hawaiian archipelago, consists of five extant and one recently extinct species. Diellia is morphologically highly variable, and a unique combination of characters has led to several contrasting hypotheses regarding the relationship of Diellia to other ferns. A phylogenetic analysis of four chloroplast loci places Diellia within “black-stemmed” rock spleenworts of the species-rich genus Asplenium, as previously suggested by W. H. Wagner, Jr. Using an external calibration point, we estimate the divergence of the Diellia lineage from its nearest relatives to have occurred in the early Miocene matching an independent estimate for the renewal of Hawaiian terrestrial life in the Miocene. We therefore suggest that the ancestor of the Diellia lineage may have been among the first successful colonists of the newly emerging islands in the archipelago. Disparity between morphological and nucleotide sequence variation within Diellia is consistent with a recent rapid radiation. Our estimated time of the Diellia radiation is younger than the oldest island of Kaua’i but older than the younger major islands of Maui, Lana’i, and Hawai’i.

1 - University of California, Berkeley, Integrative Biology, University and Jepson Herbaria, 1001 Valley Life Sciences Building, Berkeley, California, 94720-2465, USA
2 - National Tropcial Botanical Garden, Department of Conservation, Kalaheo, Kaua'i, Hawaii, 96741, USA
3 - Caroll College, Department of Natural Science, 1601 North Benton Ave., Helena, Montana, 59625, USA
4 - University of Tartu, Institute of Botany and Ecology, Tallinn Botanic Garden, Tallinn, 11913, Estonia
5 - University of Goettingen, Department of Systematic Botany, Albrecht von Haller Institute for Plant Sciences, Untere Karspuele 2, Goettingen, D-37073, Germany
6 - University of Colorado, University Museum & Department of Ecology and Evolutionary Biology, 265 UCB, Boulder, Colorado, 80309-0265, USA
7 - Natural History Museum, Department of Botany, Cromwell Road, London, SW7 5BD, United Kingdom

Keywords:
adaptive radiation
ferns
Hawai'i
historical biogeography
phylogeny
island biogeography
Miocene
divergence times estimates
Asplenium
morphological diversity
molecular diversity
Hawaii.

Presentation Type: Paper
Session: 10-1
Location: Superior B (Cliff Lodge)
Date: Monday, August 2nd, 2004
Time: 9:30 AM
Abstract ID:79