Abstract Detail

Systematics Section / ASPT

Lowrey, Tim [3], Whitkus, Richard [1], Sykes, William [2].

Biogeography and phylogenetic relationships of Tetramolopium mitiaroense from the Cook Islands, South Pacific.

Tetramolopium mitiaroense, is a new species endemic to Mitiaro, Cook Islands. The species grows only on makatea outcrops, limestone derived from fossilized fringing coral reefs. The Cook Islands Archipelago comprises 15 islands and is situated 3200 kilometers to the south of the Hawaiian Islands and 1100 kilometers to the west of Tahiti. The archipelago comprises a widely spread northern group of 7 atolls (total land area 18 sq. km.) and more compact southern group of 8 islands (Southern Cooks) (total land area 132 sq. km.). Tetramolopium occurs only on the small, flat, island of Mitiaro, which is approximately 30 square kilometers in area in the Ngaputoru Group (Atiu, Mau’ke, and Mitiaro) of the Southern Cooks. Published morphological, molecular, and geological data is reviewed to assess relationships amongst Tetramolopium taxa in the eastern Pacific and elucidate the biogeographic pattern of dispersal. The species is most closely related to Hawaiian Tetramolopium species in section Tetramolopium. Available evidence supports the hypothesis that Tetramolopium was first dispersed to the Hawaiian Archipelago from New Guinea with a secondary dispersal event from Hawaii to the Cook Islands. The geologic history of the older Southern Cooks (including Mitiaro) has involved periods of complete island submergence after the initial emergence of the active volcanoes. This submergence allowed the fringing reefs to develop that later became the makatea when the island re-emerged. The oldest makatea on Mitiaro may have been exposed for close to a million years before present thus setting the upper time limit for plant colonization. Based on migration routes and feeding behavior, the Pacific Golden-Plover appears to be the probable agent of dispersal for the taxon.

1 - Sonoma State University, Dept. of Biology, 1801 East Cotati Avenue, Rohnert Park, California, 94928, USA
2 - Manaaki Whenua - Landcare Research, P.O. Box 69, Lincoln, 8152, New Zealand
3 - University of New Mexico, Department of Biology, 167 Castetter Hall, Albuquerque, New Mexico, 87131-0001, USA

Keywords:
Asteraceae
biogeography
Tetramolopium
bird dispersal
phylogeny
Eastern Pacific
Evolution
geologic dating.

Presentation Type: Paper
Session: 43-11
Location: Cottonwood A (Snowbird Center)
Date: Wednesday, August 4th, 2004
Time: 10:45 AM
Abstract ID:220