LOWREY, TIMOTHY K.*, CHRISTOPHER J. QUINN, RACHAEL K TAYLOR, RAYMUND CHAN, REBECCA KIMBALL, AND JAN C. DE NARDI. Department of Biology, University of New Mexico, Albuquerque, NM 87131, School of Biological Science, University of New South Wales, Sydney, NSW 2052, Australia, Jepson Herbarium and Department of Integrative Biology, University of California, Berkeley, CA 94720, USA. - Molecular, morphological and biogeographical reassessment of relationships within the Vittadinia group of Astereae (Asteraceae).
VittadiniaRich. and TetramolopiumCass. (Asteraceae;
Astereae) are two Austral-Pacific genera that have long been
recognized as being closely related, having been variously merged and
segregated by different authors. The two genera encompass diverse
morphologies as well as broad and unusual distributional patterns. A
number of other genera in the region have also been implicated as
being related. We present the results of a reassessment of the
phylogenetic relationships within the Pacific taxa of
Tetramolopiumand among the Austral-Pacific
Vittadinia-Tetramolopiumgroup of genera using molecular and
morphological data. Morphological and ITS (internal transcribe spacer)
sequence data for 40 species of Camptacra, Kippistia, Minuria,
Peripleura, Tetramolopium, and Vittadinia, as well as one
semi-herbaceous species of Australian Olearia, were subjected
to cladistic analysis, separately and together. Results show both
datasets exhibit marked homoplasy indicating why generic delimitation
in the group has been historically problematic. This homoplasy may be
the result of past intergeneric hybridization and/or
convergence/parallelism among the taxa in similar arid environments in
Australia. Minuria, Peripleuraand Tetramolopiumare
paraphyletic as currently defined. Tetramolopium vagansfrom
Australia appears to represent an undescribed genus. Kippistia
suadefoliaand Peripleura diffusafall within the affinity
group of Minuriaspecies. Vittadiniaand the remaining
species of Tetramolopiumand Peripleuraform a strong
affinity group. The distribution of indels and the combined analysis
each provide evidence that the Hawaiian and Cook Island species of
Tetramolopiumare descended from New Guinea species. The
combined analysis also suggests that the Cook Island species is sister
to the Hawaiian clade. Olearia argutashows no close affinity
with either of the arborescent species of Oleariaused to root
these analyses. Further studies are needed to clarify the
relationships of other taxa (particularly in New Guinea) not included
in this study that have been linked to the
Vittadinia-Tetramolopiumgroup.
Key words: Asteraceae, ITS, morphology, phylogeny, Tetramolopium, Vittadinia