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New Marine Species Discovered in the Philippines' "Twilight Zone"

October 08, 2015

Story at-a-glance

  • Scientists from the California Academy of Sciences spent seven weeks collecting new marine species in the Philippines
  • Among the discoveries were 40 new varieties of vibrant sea slugs, or nudibranchs, and a “living fossil” heart urchin
  • New species discovered in the “twilight zone” were 15 species of fish along with multi-colored “comb jellies” from 280 feet deep

By Dr. Becker

"More humans have visited the moon than have dived to the twilight zone," Steinhart Aquarium Director Bart Shepherd told Phys.org.1 The “twilight zone” he’s referring to is “in a narrow band of mesophotic reefs, located between 150 and 500 feet deep.” There, the animals live in partial darkness and are rarely seen by human eyes.

The area is part of the Philippines’ Verde Island Passage, known as the Coral Triangle, one of the most biologically diverse marine areas on the planet. There, scientists from the California Academy of Sciences spent seven weeks collecting new marine species, including sea slugs, barnacles, and heart urchins.

The new species were discovered not only in the “twilight zone” but also shallows and clear-water reefs. Terry Gosliner, PhD, Senior Curator of Invertebrate Zoology at the California Academy of Sciences and a principle investigator of the expedition told Phys.org.2

"The Philippines is jam-packed with diverse and threatened species — it's one of the most astounding regions of biodiversity on Earth… Despite this richness, the region's biodiversity has been relatively unknown.

The species lists and distribution maps that we've created during our years surveying the country's land and sea will help to inform future conservation decisions and ensure that this incredible biodiversity is afforded the best possible chance of survival."

Sea Slugs, Heart Urchins, and More

Among the discoveries were 40 new varieties of vibrant sea slugs, or nudibranchs, with Gosliner noting:

“This remarkable stretch of coral rubble was carpeted in colorful nudibranchs… It was like an underwater Easter egg hunt. It was one of the most exciting scientific dives of my 50-year career."

Then there was the new heart urchin, which is described as a “living fossil” possibly related to the Prenaster genus, which is a fossil species that lived about 50 million years ago. Exploration in the twilight zone is slightly more challenging, as researchers only have about 30 minutes to explore before an hour’s long period of decompression on the way back to the surface begins.

Although new species may be discovered at a rate of 10 per hour or more, in the rarely visited depths, time is short when exploring the deep. Among the new species discovered in the twilight zone were 15 species of fish along with multi-colored ctenophores, or “comb jellies,” from 280 feet deep.

According to Phys.org:3

“When hungry, the animal deploys long, sticky, and hair-like tentacles into the surrounding waters to reel-in plankton, turning mealtime into an impressive display.”

The researchers will use DNA sequencing and other tools to analyze all specimens collected, and the new species will be available for further study in the future. The hope is that the discoveries, along with a related aquarium exhibit, will promote awareness and conservation efforts to protect the ocean.

Is It Ethical to Collect New Species?

The California Academy of Sciences hopes to use some of the “twilight zone” species for a new exhibit at the Academy's Steinhart Aquarium, expected to open in the summer of 2016. There are ethical considerations to exploring new depths in the ocean and, certainly, to collecting its inhabitants.

The researchers involved in this exploration were not out to collect more than they needed or to simply fill their bags, “which is why the result of seven weeks of collecting in the richest marine ecosystem on the planet could fit on a large dining room table if it were arranged neatly enough,” Scientific American reported. They continued:4

“… [T]hey’re seeking scientific value, data that furthers their understanding of a place or process. What most often determines whether a specimen is collected or not is how novel or unusual the collector thinks that organism is.

New species are the holy grail, but a new record of a species in a particular region or habitat, or a unique coloration or morphology, or a noteworthy association with some other organism, or features that make a specimen a particularly good representative of a species are all considered scientifically valuable.”

Each species will be carefully identified with its location and habitat recorded. It will have its DNA analyzed and be carefully recorded into the Academy’s scientific collections. Scientific American explained:5

“Once this work is complete, scientists from anywhere in the world will be able to search that database, gather information, and request to borrow a specimen or acquire a tissue sample that might provide key information for their research.

In addition to being used for species identification and to document the biodiversity of an area, scientific specimens like these can be used to document species distribution and evolution or to study the spread of disease or the impacts of climate change.

While the Philippines will retain ownership of the collection, the Academy has pledged to maintain it and ensure its availability to scientists for the long haul.”

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Sources and References

  • 1, 2, 3 Phys.org June 8, 2015
  • 4, 5 Scientific American June 26, 2015
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