In the children's story, the ugly duckling turns out not to be a duck at all, but a swan. Now, fish are telling a similar tale. Researchers have identified an unusual larva (inset) that grows up to be a newly described species, the yellow-spotted golden bass (above). Scientists first took notice of the young fish when they saw its picture in a publication. It seemed like it might be the larva of a sea bass, but it was unique in having seven elongated spines sticking out from its back. These flexible spines may cause potential predators to mistake the 1.4-centimeter animal for a jellyfish, or may simply make it look too big to eat. The larva was collected from shallow water between Florida and Cuba. But a DNA sample didn't match any known fish, so its identity was a mystery. Until now. A survey of biodiversity down to 300 meters off the Caribbean island Curaçao netted a new species, Liopropoma olneyi, the yellow-spotted golden bass. When researchers entered a piece of the bass's DNA sequence known as a bar code  into their database, the bar code matched that of the larva , researchers report this week in PLOS ONE. Generally, fish eggs float toward the sea surface and the young drift in the surface currents until they mature and swim to the depths where they live out their lives. So, often, the larvae and adults are not found in the same place, and because they look very different, researchers have a hard time figuring out what larvae will grow up to be. However, DNA barcoding is helping solve those mysteries, the researchers say.
ScienceShot: Unusual Larva Becomes New Species of Fish