WASHINGTON - In a new study, scientists have shown that when the coast horned lizard moved north from Baja California and spread throughout the state, it diverged into at least two new species, making it a total of three species.
“When you stack up all the data sets, they all support three species,” said lead author Adam Leache, a National Science Foundation bioinformatics postdoctoral fellow at UC (University of California) Davis.
“If you were to pick only one data set, you would get a different number of species. One lesson we learned about the speciation process is that you can’t rely on one type of data to accurately track a species’ history,” he added.
Aside from the oldest and original species, P. coronatum, found only in southern Baja California, the researchers identified a new species, P. cerroense, in central Baja and a third, P. blainvillii, whose range extends from northern Baja to Northern California.
Within the third, wide-ranging species, the study’s authors found enough genetic and ecological differences to suggest there are at least three distinct populations of P. blainvillii, each requiring separate management and protection.
The findings have implications for conservation efforts, because coast horned lizard populations are in decline from southern Baja California to Northern California due to several factors.
“This could have an impact on the number of species that we recognize on the planet, because many species are young like this,” said Jimmy McGuire, UC Berkeley associate professor of integrative biology.
In particular, the number of species in California could be substantially underestimated because even well studied groups like horned lizards are likely to be comprised of multiple cryptic species, according to McGuire.
Studies integrating diverse data sets and focusing on the question of gene flow between lineages will almost certainly result in the discovery of many new species, he added.
Over the course of millions of years, populations of horned lizards migrating northward have separated and diverged from one another, producing an array of genetic lineages all along the western coast of North America that are adapted to unique ecological niches, according to the study.
“The genetic differences between the populations of horned lizards in California are striking - nobody could have predicted this high degree of differentiation simply by looking at the physical differences between the lizards,” Leache said.
Given enough time and continued environmental protection for the lizards to persist for the long-term, it’s likely that the California horned lizards, like those in Baja California, will also evolve more dramatic physical differences through natural selection. (ANI)