New cave creature is like a ‘swimming centipede’

Remipede Lasionectes, a species previously known from the Caicos Islands, uses its paddle-like appendages to gracefully glide in a tight turn through the cave water. (Credit: Jørgen Olesen/Natural History Museum of Denmark)

A recent research trip to the Caribbean may have hit the jackpot: the discovery of at least one new species of ocean life.

“We collected what we believe is a new remipede species, likely related to those found in the Yucatan Peninsula of Mexico,” says Tom Iliffe, professor at Texas A&M University at Galveston. “Other new species of cave and marine life will likely be found once further examination is complete.”

Iliffe has explored more than 1,500 underwater caves and has discovered more than 350 species of marine life. He notes that there is a sense of urgency surrounding his research.

“Time is critical and running out for this research,” Iliffe says. “Many of these caves are in danger of pollution or destruction. One cave, in which we found a rich assortment of marine animals on our last trip here, is now polluted and lifeless. If we don’t obtain this information now, it may be lost to us forever.”

Remipedes and scale worms

The team sought to dive and collect rare animals from anchialine caves in the Turks and Caicos Islands, a group of islands located at the southern end of the Bahamas Archipelago.

Anchialine caves are inland caves containing saltwater pools that rise and fall with the tides. In the depths of such caves, scientific cave divers have discovered an incomparable variety of eyeless and colorless animals. These remarkable species have close relatives from similar cave habitats on opposite sides of the Atlantic Ocean suggesting exceedingly ancient origins.

The team’s goal was to obtain biological specimens to investigate the genetic diversity of rare cave life in the area, especially concentrating on swimming scale worms, as well as unique cave dwelling crustaceans known as remipedes. One such scale worm, Pelagomacellicephala iliffei, was named after Iliffe when he discovered it in 1982.

Another research goal was to understand the molecular mechanisms of adaptation in these rare animals. Both remipedes and scale worms are top predators in saltwater caves, but their lifestyle and evolutionary history are quite different.

Unknown ancestor

Unlike scale worms, the ancestor of remipedes are unknown, but previous research by study leader Brett C. Gonzalez, a postdoctoral researcher at the Smithsonian–National Museum of Natural History, showed that deep-sea scale worms are closely related to those living in caves.

Gonzalez says the team sought to collect genetic material from the location where the worm was first discovered several decades ago.

“I plan to use DNA sequencing technology to investigate similarities between these specimens and those living in the deep sea. This will aid us to understand how animals can adapt and live in such lightless, food poor habitats,” says Gonzalez, who worked with Iliffe as a Texas A&M graduate student.

“Extreme environments like anchialine caves and the deep sea drive some scale worms into the water column, enabling them to survive as predatory swimmers. Now, our team is the first to capture this swimming behavior on film and use it for detailed video analysis.”

At first glance, remipedes might easily be mistaken for swimming centipedes rather than crustaceans. They have a head and long body with 15-42 similarly shaped segments, each with paddle-shaped limbs. All remipedes are eyeless and lack body pigmentation—typical adaptations to life in the depths of lightless saltwater caves. Four of the 29 known species of remipedes come from caves in the Caicos Islands.

The next step for the team is to carry out detailed molecular and morphological analyses of all the specimens collected. This research should provide intriguing insights into evolution and adaptation of animals from these uniquely fascinating cave environments. Later this year, Iliffe and his team will continue their exploration, investigating caves in Belize and the Yucatan Peninsula.

The team had funding from the Smithsonian’s Global Genome Initiative, whose mission is to gather genetic information on all forms of marine life, and an NSF Graduate Research Fellowship.

Additional members of the research team are from the University of Copenhagen; the Natural History Museum of Denmark; the Monterey Bay Aquarium Research Institute; and the National Research Council of Italy, Institute for Water Research.

Source: Texas A&M University