 Isabela is the most recently formed island tortoises inhabit, so its populations have had less time to evolve independently than populations on other islands, but according to some researchers, they are all genetically different and should each be considered as separate species.Phylogenetic analysis may help to "resurrect" the extinct species of Floreana ("C. nigra") – a species known only from subfossil remains.Some tortoises from Isabela were found to be a partial match for the genetic profile of Floreana specimens from museum collections, possibly indicating the presence of hybrids from a population transported by humans from Floreana to Isabela, resulting either from individuals deliberately transported between the islands, or from individuals thrown overboard from ships to lighten the load.