Reported by ScienceDaily
At first glance it looks exactly like a seahorse. It has the same horse-shaped head tilted down from the body, the same curled and grasping tail, and in the males a fully enclosed pouch for brooding the young.
But this little fish, no longer than your thumb, is not a seahorse, as we report in our new study published in the Journal of Lost Species . This is Australyichthys aegis , a newly described fish from the deep reefs off southern Australia. We have given it the common name helmethead sea muppet, after the domed, helmet-like crest on its head.
Its scientific name follows the same idea: in Greek mythology the aegis was a protective shield. Together with its two relatives, the bullneck sea muppet ( A. minotaur ) and the paradoxical sea muppet ( A. paradoxus ), it makes up a small group we nickname the sea muppets.
More from the original report
All three, we have now shown, belong on their own branch of the family tree. The seahorse look has arisen more than once, and these fish are a case of it evolving well away from the true seahorses. That evidence had been sitting in museum drawers, misfiled, for decades.
Every known specimen was brought up by accident, caught in trawl nets or dredges working the seafloor between about 50 and 125 meters down. The single specimen of A. aegis came up in 2006 near the Gambier Islands, at the mouth of South Australia's Spencer Gulf.
The dredge that caught it was sampling for small shelled animals known as brachiopods during a natural history expedition. Because that expedition was after invertebrates, the fish was mistakenly catalogued into the invertebrate collection of the South Australian Museum, where it sat unrecognized for years.
After each chance capture the fish were preserved, then largely forgotten. The rest are held in Australian museum collections, among them the Australian Museum, Museums Victoria and CSIRO.
The whole genus is known from just seven specimens gathered over about 65 years, scattered across more than 2,500 kilometers of coastline, and nothing has been collected in nearly two decades.
The specimens…