DNA can unite species that were thought to be different. Scientists believed these Sea Stars to be two different species when first discovered. Further studies of their DNA revealed that they were actually different life stages of the same animal.
Summary
Cryptic Sea Stars
Adult Sea Star (Choriaster granulatus,)
From Bokissa Island, Southern Pacific, 2005
Juvenile Sea Star (Choriaster granulatus)
From Guam Island, Western Pacific, 200
Collection
Story
Sequencing the DNA of organisms often allows you to tell them apart and has led to many discoveries when people thought single species were present in a particular place, but DNA told them there were multiple. You probably have heard of the fact that people now think there are several species of giraffe and things like that.
Well, sometimes the opposite happens. These two sea stars you see in front of you here were thought to be two different genera. These are much higher levels in the taxonomic hierarchy than species are. They’re so different that people really classify them in different groups. But you never see small ones of the big guy, or big ones of the small guy, and if you are really observant you can look into the small guy and you never find gonads in it, meaning that they are all juveniles. So some people decided that maybe there’s something else going on here and these could be stages in the growth of a single animal. We tested that with DNA and found that they are indeed the same animal and as a result these two species now have become one.
Gustav Paulay
Curator, Invertebrate Zoology*
Florida Museum of Natural History
Exhibit
On display Sept. 23, 2017-Jan. 7, 2018, Rare, Beautiful & Fascinating: 100 Years @FloridaMuseum celebrated the Museum’s rich history. Each Museum collection was asked to contribute its most interesting items and share the stories that make them special. Though the physical exhibit is closed, this companion website remains online, providing an opportunity to experience the Florida Museum’s most treasured specimens.
Exhibit Area: Looking Ahead
Theme: DNA Discoveries
Want to see more? Explore more than 300 breathtaking color photos of plants, animals, fossils and cultural heritage materials from the Florida Museum of Natural History’s collections in the award-winning book All Things Beautiful available from the University Press of Florida.
*This title was accurate at the time the exhibit was on display in 2017. Please visit the collection website to verify current staff and student information.