Discovering the mola tecta, a new species of sunfish

Read the story about how a sunfish washing up on our beaches and lying in our store rooms, has become the first new species of sunfish to be described in 100 years.

In 2008, Japanese scientists published a paper in which tissue samples from a large number of sunfish were analysed. At the time, only two species of Mola were known, Mola mola and Mola ramsayi, but to everyone’s surprise, three distinct species emerged.

This started a worldwide search through early literature and collections to try and determine what this third species might look like – and if it had already been previously described.

Close examination of the material held at Te Papa revealed that around half the specimens preserved in tanks were the new species! However, these were too small to give a clear idea of the changes in body shape proportions with growth and for tissues to ground the analysis.

They are also preserved, and preserved material cannot be sampled for DNA analysis, which is needed to help validate the taxonomy.

A call went out to the Ministry of Primary Industries Scientific Observers to collect a larg(ish) specimen, should one be taken as by-catch.

In 2015, a 52kg specimen was acquired. This will be designated as the holotype or name-bearing specimen.

In May 2016, scientists from Japan and Australia came to Te Papa to spend time examining all our material and preparing the paper to formally describe this new species.

Te Papa scientists examine the new Mola tecta sunfish, 2016. Te Papa

Mola tecta

In Jul 2017, the new species of sunfish was formally described as Mola tecta. 'Tectus' is latin for hidden, we wanted to show that this sunfish was in front of us all this time, but it was hidden from view as we hadn't looked at enough material to pick up on subtle differences between species.

This discovery shows that new things can be found right in front of us. This sunfish was literally washing up on beaches in good numbers, and yet we hadn't recognised it.

It's the first new species of sunfish to be described in 100 years.

Hear fish expert Andrew Stuart talk about the new discovery on Radio NZ

Marianne Nyegaard with the ‘Hoodwinker’ sunfish. Photograph courtesy of Murdoch University