About 13 different species of finches inhabit the Galápagos Islands today, all descendants of a common ancestor from the South American mainland that arrived a few million years ago. Genetically, there are four distinct lineages, but the 13 species are currently classified among three genera. The first lineage to diverge from the ancestral lineage was the warbler finch (genus Certhidea). Next to diverge was the vegetarian finch (genus Camarhynchus), followed by five tree finch species (also in genus Camarhynchus) and six ground finch species (genus Geospiza). Molecular analysis in 1999 shows, the vegetarian finch is genetically no more similar to the tree finches than it is to the ground finches, despite the fact that it is placed in the same genus as the tree finches. Based on this finding, it is reasonable to conclude that the vegetarian finch
a. should be re-classified as a warbler finch.
b. is not truly a descendent of the original ancestral finch.
c. is no more closely related to the tree finches than it is to the ground finches, despite its classification.
d. is a hybrid species, resulting from a cross between a ground finch and a tree finch.