In 2015, researcher Greg Rouse at the Scripps Institution of Oceanography and colleagues described a new species, the ruby seadragon, using dead specimens found in museums and later pulled up from trawls.
The researchers predict that the Ruby Seadragon may have lost its appendages owing to evolution.
The footage was published Thursday in a study featured in Marine Biodiversity Records. While common and leafy seadragons tend to live in shallow kelp beds, the ruby seadragon's coloration suggested that scientists would have to dive a bit deeper to catch a glimpse, Eva Botkin-Kowacki reports for the Christian Science Monitor.
"It was really quite an awesome moment", Josefin Stiller, a marine biologist with Scripps Oceanography and co-author of the new study, said in a statement.
Video footage of the ruby seadragon was captured using a remotely operated vehicle with a low-light video camera, because it lives at depths of more than 164 feet (50 metres). Instead of living amongst seaweed and kelp, the ruby seadragon prefers the company of sea sponges.
Using the preserved specimens, the researchers were able to assemble a rotating 3-D model of the new seadragon using a CT (computer tomography) scan of 5,000 X-ray slices.
"Until then, no one suspected a third species of seadragon existed", says Greg Rouse, who first described the dragon from a preserved specimen collected almost a hundred years ago. It differs from the other two, weedy and leafy seadragons, in its colour and lack of "leaves" - appendages that grow off the dragons for camouflage.
Scripps Institution of Oceanography partnered with the Western Australian Museum and launched a scientific expedition off the coast of Western Australia to find Ruby Seadragons in the wild.
"It was really quite an unbelievable moment when we discovered that the ruby seadragon lacks appendages". Its closest relatives, the leafy and common seadragon, inhabit much shallower depths of 3-25 meters.
This fortunate run, all undertaken during a single day, revealed some never before known details about the lives of ruby seadragons. Its ruby color is probably an evolutionary trait, as camouflage in the deeper, dimly lit waters, they added.
Rouse says learning more about this species shows that, "We've still got so much more to do in terms of documenting biodiversity".
Seadragons are marine fish in the same taxonomic family as pipefish and seahorses.
The ruby seadragon also has a curled tail, similar to a seahorse, which researchers think could help this fish hold on to objects in high-surge waters.
This latest discovery confirms that ruby seadragons lack ornate leaf-like appendages, a feature that scientists had considered to be distinguishing characteristics based upon the two known species, the common and leafy seadragons. "Western Australia has such a diverse range of habitats, and each one is deserving of attention".