East Pacific Tracks

This account of the East Pacific tracks illustrations and information from the following article:

Grehan, J. R. 2001: Biogeography and evolution of the Galapagos: integration of the biological and geological evidence. Biological Journal of the Linnean Society, 74: 267-287

These distributions share Galapagos and exclude all or most of Central America while connecting to either or both North and South America. These tracks exemplify a common spatial pattern for organisms with passive (e.g. flightless weevils) and active (e.g. wasps) dispersal mechanisms. The American relatives of some groups comprise vicariant distributions over a geographic range that is similar to other taxa also comprising more than one vicariant taxon.

Flightless Galapaganus weevils Five Galapagos species and three species in Ecuador and Peru.
Wasp sister species Tachysphex galapagensis and T. peruanus
Galapagos snake Alsophis biserialis and its sister species A. elegans in Peru and southern Ecuador (Blue track and polygons). Galapagos snake Pilodrya hoodensis and its Chilean relative P. chamissonis (red track and polygons).
Global distribution of the plant family Nolanaceae with one Galapagos species and remaining 82 species in Peru and Chile  Lizard genus Microlophus with at least three Galapagos species and 14 mainland species with a combined range between Ecuador and northern Chile
Cotton sister species Gossypium klotzschianum and G. davidsoni linking the Galapagos with Baja California
Foxglove genus Gambelia in California and Mexico and Galvezia in Galapagos. The track for Galvezia comprises Galapagos, Ecuador and Peru
The staphylinid beetle genus Rothium connects Galapagos with both Mexico and Ecuador
Sorpion family Iuridae with an endemic genus on Galapagos and related genera distributed between western North America and Chile.
An extension of the East Pacific track into the Caribbean with the Phyllodactylus lizards of Galapagos and their relatives in Columbia, Venezuela and Puerto Rico This track bypasses Panamanian central America as do the other East Pacific tracks.
This Caribbean connection via North and South America is also found in the distribution of the plant genus Lycium where the Galapagos 'fills' a geographic gap west of Central America complementing the Caribbean distribution to the east.
A biogeographic interelationship between East Pacific and Caribbean distributions may also apply to the Galapagos finches. Designation of Tiaris obscura as the nearest mainland relative results in a Galapagos-South America track.
Both Tiaris and the Caribbean Melanospiza comprise the Galapagos finch sister group thus extending the East Pacific track to include the Caribbean basin