RENNER, SUSANNE S.* AND DONALD B. FOREMAN. Department of Biology, University of Missouri - St. Louis, St. Louis, MO 63121, and Royal Botanic Gardens Melbourne. - Molecular phylogenetics and biogeography of Atherospermataceae -- two Chile - Australia/New Zealand disjunctions.
The Atherospermataceae consist of 14 species in 7 genera of which
Laurelia is probably the best known because of its disjunct
range, with one species occurring in Chile and Argentina, the other in
New Zealand. A second Chilean species of atherosperm, Laureliopsis
philippiana, was excluded from Laurelia in a monograph of
the family by R. Schodde (1969). To test Schodde's hypotheses on
affinities of and within atherosperms, we sequenced three chloroplast
DNA regions, the rbcL gene, the rpl16 intron, and the
trnL-trnF spacer (together comprising 2614 bp), for most
species and all genera, as well as all potential outgroups. In
agreement with Schodde's phenetic analysis, the molecular data show
that the Chilean Gomortega keule, the sole species of
Gomortegaceae, is the closest relative of atherosperms (with >90%
bootstrap support in a larger parsimony analysis of 24 sequences of
Laurales). Also in agreement with Schodde, the two Chilean species,
Laureliopsis philippiana and Laurelia sempervirens group
with different eastern Australian and New Zealand species. Together
with the distribution of other related species in New Caledonia,
Tasmania, and New Guinea this attests to the importance of
trans-oceanic dispersal of atherosperms during the Tertiary.
Key words: Atherospermataceae, Australia, Chile, disjunctions, molecular phylogenetics