Featured Research

from universities, journals, and other organizations

For Horned Lizard, Horns Alone Do Not Make The Species

Date:
July 27, 2009
Source:
University of California - Berkeley
Summary:
Counting the horns of California's horned lizard, or coast horned lizard, is one way to try to distinguish separate species, but a new study shows that to be unreliable. Biologists considered genetic, morphological and ecological data to separate the species into three, ranging from Baja to Northern California.

This coast horned lizard from Torrey Pines State Park is distinctly different from populations in central and southern Baja California, and has been designated a new species, Phrynosoma blainvillii.
Credit: Chris Brown/USGS

How do you recognize a new species? A thorough study of the million-year evolution of California's horned lizards, sometimes referred to as "horny toads," shows that when it comes to distinguishing such recently diverged species, the most powerful method integrates genetic, anatomical and ecological information.

In the study, published in the journal Proceedings of the National Academy of Sciences, researchers from the University of California, Berkeley, and the U.S. Geological Survey consider all these criteria to show that when the coast horned lizard (Phrynosoma coronatum) moved north from Baja California and spread throughout the state, it diverged into at least two new species.

"When you stack up all the data sets, they all support three species," said lead author Adam Leachι, a recent UC Berkeley Ph.D. recipient who is now a National Science Foundation bioinformatics postdoctoral fellow at UC 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."

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. Among these are loss of lowland habitat from agriculture and urbanization and the introduction of Argentine ants, which displace the more nutritious harvester ants, the favored diet of the lizards. The lizard is on the International Union for Conservation of Nature's Red List of Threatened Species, as are California's two other horned lizards, the desert and flat-tailed horned lizards.

"For decades, it has not been clear what might be useful conservation units within the declining horned lizards in coastal California. Our study finally gives some clarity and direction for conservation actions to follow," said co-author Robert Fisher, a research biologist at the U.S. Geological Survey in San Diego, Calif.

For over 100 years, scientists have been trying to distinguish species among coast horned lizards, with the number of recognized species ranging from 1 to 6 depending on the author. These prior studies were reliant almost entirely on morphology. But when it comes to recently diverged species like the coast horned lizard, where morphological differences are subtle, it can be difficult to distinguish species, according to co-author Jimmy McGuire, UC Berkeley associate professor of integrative biology.

"This sort of analysis is going to be necessary in order to tackle questions of recent speciation," McGuire said. "Lineages that have been separated for a long time are not controversial – we have no trouble distinguishing chimps from humans, for example – but it is trickier with species that are younger and thus less morphologically heterogeneous."

"This could have an impact on the number of species that we recognize on the planet, because many species are young like this," he added.

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, McGuire said. 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," Leachι 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.

Leachι and McGuire, as well as the other UC Berkeley coauthors of the paper – Michelle S. Koo, Carol L. Spencer and Theodore J. Papenfuss – are affiliated with the campus's Museum of Vertebrate Zoology.

The study was funded by the National Science Foundation, The Nature Conservancy, California Department of Fish and Game, California Department of Parks and Recreation, Metropolitan Water District, U.S. Fish and Wildlife Service and U.S. Department of Defense.


Story Source:

The above story is based on materials provided by University of California - Berkeley. Note: Materials may be edited for content and length.


Cite This Page:

University of California - Berkeley. "For Horned Lizard, Horns Alone Do Not Make The Species." ScienceDaily. ScienceDaily, 27 July 2009. <www.sciencedaily.com/releases/2009/07/090721163115.htm>.
University of California - Berkeley. (2009, July 27). For Horned Lizard, Horns Alone Do Not Make The Species. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2009/07/090721163115.htm
University of California - Berkeley. "For Horned Lizard, Horns Alone Do Not Make The Species." ScienceDaily. www.sciencedaily.com/releases/2009/07/090721163115.htm (accessed July 28, 2014).

Share This




More Plants & Animals News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Sea Turtle Hatchlings Emerge from Nest

Raw: Sea Turtle Hatchlings Emerge from Nest

AP (July 27, 2014) — A live-streaming webcam catches loggerhead sea turtle hatchlings emerging from a nest in the Florida Keys. (July 27) Video provided by AP
Powered by NewsLook.com
Trees Could Save More Than 850 Lives Each Year

Trees Could Save More Than 850 Lives Each Year

Newsy (July 27, 2014) — A national study conducted by the USDA Forest Service found that trees collectively save more than 850 lives on an annual basis. Video provided by Newsy
Powered by NewsLook.com
What's To Blame For Worst Ebola Outbreak In History?

What's To Blame For Worst Ebola Outbreak In History?

Newsy (July 27, 2014) — A U.S. doctor has tested positive for the deadly Ebola virus, as the worst-ever outbreak continues to grow. Video provided by Newsy
Powered by NewsLook.com
The New York Times Backs Pot Legalization

The New York Times Backs Pot Legalization

Newsy (July 27, 2014) — The New York Times has officially endorsed the legalization of marijuana, but why now, and to what end? Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins