Scientists discover new living fossil. What is a living fossil?

A living fossil is not Russell Johnson (the professor from Gilligan’s Island) or dear Zsa Zsa Gabor (God bless you for holding on!).

I’ll chop it down to say that a living fossil is an organism that more closely resembles a fossil than anything living. For instance, the Atlantic horseshoe crab resembles the fossil record of trilobites more so than anything living. You can also think of living fossils as animals that have gone unchanged after millions of years therefore resembling the fossil record of their ancestors very closely. For instance, alligators and crocodiles haven’t evolved much in the past 230 million years. Horseshoe crabs have gone unchanged in the past 450 million years.

Most recently, a team led by Smithsonian scientists discovered a new living fossil, a primitive eel (Protoanguilla palau), from 10 specimens gathered from a cave in Palau. Palau is an island located in the Pacific 500 miles east of the Philippines and 2,000 miles south of Tokyo. What the scientists noticed was unique to this species (setting it apart from the 800 species of living eels) was the presence of a second upper jaw bone, fewer than the standard 90 vertebrae, and a full set of bony toothed gill rakers. Also, according to the press release from the Smithsonian, “The team’s analyses of total mitochondrial DNA indicate that P. palau represents an ancient, independent lineage with an evolutionary history comparable to that of the entire order of living and fossil eel species.”

8 reasons to kick your heels about eels

American eel (Anguilla rostrata)

Image by Charles & Clint via Flickr

In no particular order here are some interesting (and exciting) facts about eels. In college I built some eels ladders for a stream in southern New Jersey so these little critters do have a special place in my professional heart.

  1. Moray eels have the ability to tie their bodies in knots and use this to gain leverage when tearing food.
  2. Electric eels are not true eels at all. They are knifefish. There are about 800 species of true eels.
  3. Eels can swim forward, as well as backward.
  4. Some eels travel up to 4,000 miles to breed, a trip taking up to seven months. It is believed that eels do not eat during this long journey. Instead, they use their body fat and muscle tissue for nutrients. The Sargasso Sea is the mating area that eels from all over Europe and North America swim to to mate and lay eggs. After the eel larvae hatch, they then make the long swim back to North America and Europe. The eel is termed catadromous because of its journey from freshwater to the depths of the ocean to spawn.
  5. Eels start life as transparent larva (leptocephal) and remain in that state for 6 to 12 months. During this time they can float thousands of miles through the open seas. After the larval phase, they become elvers and although not sexually mature, they look more like an adult eel.
  6. Eels resemble snakes but actually do have fins. The dorsal and anal fins are fused together that form a single ridge along their elongated body.
  7. Eel blood is toxic to humans and other mammals, but the cooking procedure and human digestive process destroy its toxic protein which is good since they are a popular food in Japan and China.
  8. You can fish for eels with any kind of cut bait. American eels (pictured) are a popular bait for crabbing and fishing.