Deep-sea fish diversity surprises scientists

Hime Perhistion - Male
A male specimen of the newly described Hime Perhistion species of deep-sea aulopis
Image: Carl Struthers
Source: National Museum of New Zealand Te Papa Tongarewa

Media contact: Alex Dook

The closer you look at any group of like objects, the more differences can appear. Researchers from Museum Victoria and the Museum of New Zealand Te Papa Tongarewa have formally described a new genus and two new species of fish belonging to the family Aulopidae – small deep-sea fishes variously known around the world as Flagfins, Threadfins, Sergeant Bakers, or just Aulopus.

The researchers used DNA tools to separate specimens found in Australasian waters from what was previously considered a single worldwide genus.

"It was thought that these fishes were widely distributed throughout much of the Pacific Ocean," said Martin Gomon, Senior Curator of Ichthyology with Museum Victoria. "But actually, there are different species inhabiting different areas."

Aulopids are found at sea depths of between 200m and 500m. Dr Gomon and Te Papa colleagues Carl Struthers and Andrew Stewart were able to isolate what they describe as the New Australasian Aulopidae in waters surrounding New Zealand and along the east coast of Australia. The researchers found one of the two species to be so different, that they recommended it be placed in a totally different genus, which they named Leptaulopus, or "slender Aulopus".

Dr Gomon says the latest research was based on DNA analysis of specimen samples collected in Australia, New Zealand, and Japanese waters. The Australasian Aulopus has a taller and more colourful dorsal fin in males than specimens from Japan and other regions, but it was the DNA testing that confirmed the local version was distinct from those occurring in other regions.

"The morphological (form and structure) factors were identified by Japanese researchers in 1989. We are pleased to have found the DNA evidence to justify the reassignment of one to a new genus, as proposed by Shimizu and Yamakawa in 1989 and Thompson and Stewart in 2006."

Species is the most specific of major taxonomic ranks used to classify living organisms, with a genus being the next broadest rank in the hierarchy.

The research findings, entitled "A New Genus and Two New Species of the Family Aulopidae (Aulopiformes), Commonly Referred to as Aulopus, Flagfins, Sergeant Bakers or Threadsails in Australasian Waters", were published by the Japanese Society of Systematic Zoology at the end of last year.

Museum Victoria Public Relations contact:
Alex Dook, 8341 7141 / 0478 348 880,

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Image Gallery

Collection map Leptaulopus erythrozonatus