Two live ruby seadragons have been captured on video for the first time since the species was identified in 2015.
Sea dragons of the leafy (Phycodurus eques) and common (Phyllopteryx taeniolatus) varieties have long been recognised in southern Australian waters, but the new species (Phyllopteryx dewysea) was known only from preserved museum specimens that until recently had been confused with common seadragons.
As the ruby seadragon was believed to live considerably deeper than the other species, beyond recreational scuba-diving limits, the Scripps Institution of Oceanography researchers deployed a mini-ROV with low-light video camera in the Recherche Archipelago in Western Australia last April.
Despite adverse weather conditions, they succeeded in obtaining the first images of two ruby seadragons at around 54m, and were able to observe their habitat and behaviour.
P dewysea lacks the dermal appendages that the other species use for camouflage. The researchers, led by Greg W Rouse, believe this is because its habitat is sparser and the appendages could cause unnecessary drag, and think the species relies on its coloration for camouflage in the lower-light conditions found at depth.
Like its relative the pipe horse, but unlike the other two species of seadragons, the ruby version has a prehensile tail. This was not observed in use but it was thought possible that the seadragon could use it to get a grip on the reef in strong surge conditions.
The team recommends that the ruby seadragon should join the other two species in being declared protected as soon as possible.
Their report is published by Marine Bioversity Records and can be read here
