A Fish Tale
A curator discovers that whalefishes, bignose fishes and tapetails are all really the same kind of fish at different life stages
- By Joseph Caputo
- Smithsonian magazine, April 2009, Subscribe
A juvenile tapetail in the process of becoming an adult grows a huge liver. G. David Johnson / NMNH, SI
Appearances can be deceiving. For decades, scientists thought that whalefishes, bignose fishes and tapetails came from three different families of fish. But G. David Johnson, a curator at the National Museum of Natural History, recently proved that all three are the same kind of fish at different life stages—a finding comparable to finding out that a baby gerbil will grow up to become either a squirrel or a chipmunk. (It won't.)
The transformation of a juvenile tapetail into an adult bignose fish or whalefish demonstrates one of the most extreme examples of metamorphosis in vertebrates. To become a bignose, a tapetail's upper jawbones fuse to its nasal bone, it loses its stomach and esophagus and lives off its liver.
Johnson's research relied on the capture of a female in the midst of metamorphosis, comparative anatomical studies and DNA analyses. The discovery also explains why past researchers had found only female whalefishes and male bignose fishes. The "missing" males and females were not missing at all. They were two very different-looking sexes of the same fish. The answer was right there all along—or, as Johnson puts it, "Well, duh!"
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Related topics: Fish Theories and Discovery
Additional Sources
"Deep-sea mystery solved: astonishing larval transformations and extreme sexual dimorphism unite three fish families," by G.D. Johnson et al. Biology Letters. (Jan. 20, 2009)
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Comments (2)
Whalefishes, which are not whale-like in size ( females grow up to 16 inches and mature males are no larger than 2.5 inches ) are named for the shape of their body. The approximately 20 known species of whalefishes are found throughout the world’s open oceans. - from Underwatertimes.com News Service
Posted by s. spann on May 10,2009 | 11:45 PM
I went to the Smithsonian website to look at more images of tapetail fishes various transformations. However, I was disappointed not to find a scale to determine their size. No where can I determine if these fish are two inches or two feet long.
Posted by E. K. Bacon on March 26,2009 | 07:47 PM