New publication: Molecular and morphological data reveal a new ocean sunfish species

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While clearly not a marine mammal, we are very pleased to highlight the work by Murdoch University’s PhD candidate Marianne Nyegaard and colleagues who have just described a new species of ocean sunfish. Incredible that we are still discovering new large animals!

Title of the publication is:

Hiding in broad daylight: molecular and morphological data reveal a new ocean sunfish species (Tetraodontiformes: Molidae) that has eluded recognition

FULL CITATION

Nyegaard, M., Sawai, E., Gemmell, N., Gillum, J., Loneragan, N., Yamanoue, Y., Stewart, S.L. (2017). Hiding in broad daylight: molecular and morphological data reveal a new ocean sunfish species (Tetraodontiformes: Molidae) that has eluded recognition. Zoological Journal of the Linnean Society. https://doi.org/10.1093/zoolinnean/zlx040

ABSTRACT

The taxonomy of the ocean sunfishes (Molidae) has a complicated history. Currently, three genera and four species are recognized, including two in the genus Mola (M. mola and M. ramsayi). In 2009, a genetic study revealed a potential third species, Mola species C, in Southeast Australian waters. Concentrating on this region, we obtained samples and morphological data from 27 Mola sp. C specimens, genetically confirmed the existence of this species (mtDNA D-loop and cytochrome c oxidase 1), and established its morphology across a size spectrum of 50–242 cm total length. Mola sp. C is diagnosed by clavus meristics [15–17 fin rays (13–15 principal, 2 minor), 5–7 ossicles, paraxial ossicles separate], clavus morphology (prominent smooth band back-fold, rounded clavus edge with an indent), and body scale morphology (raised conical midpoints, non-branching). This species does not develop a protruding snout, or swollen dorso- or ventrolateral ridges. Body proportions remain similar with growth. A review of the historic literature revealed that Mola sp. C is a new, hitherto undescribed species, M. tecta, which we describe and diagnose, and that it is the first proposed addition to the genus Mola in 125 years. Its core distribution is likely in the temperate waters of the Southern Hemisphere.

ADDITIONAL TEXT

Incredibly, the cold-temperate marine regions off southeast Australia, New Zealand, South Africa and Chile are home to an – until now – unrecognised and undescribed species of ocean sunfish, reaching at least 2.4 meters in total length. Despite this large adult size, it nevertheless managed to evade scientific recognition by ‘hiding’ in a confusing taxonomic history of the ocean sunfishes, dating as far back as 16th century European ichthyology. Because of this, we named it Mola tecta from the Latin tectus, meaning disguised or hidden.

At smaller sizes, the new sunfish superficially resembles the other two known species, Ocean sunfish (Mola mola) and the Short sunfish (Mola ramsayi), however with growth each of the three species develop characteristic traits. As large specimens are relatively difficult to come by, handle, store and study, Mola tecta have been overlooked and its characteristics interpreted as intra-specific variation. It took genetic tools, social media and international collaboration between Australian, New Zealand and Japanese scientists to finally unlock the mystery, by bringing together information on all three species of sunfish, from the north- and southwest Pacific, for comparison.

The discovery and description of Mola tecta, the Hoodwinker ocean sunfish, was a collaboration between Murdoch University, Wellington Museum Te Papa Tongarewa, the Gemmell Lab at Otago University, Hiroshima University and the University of Tokyo.

Video footage of a small Mola tecta recorded off Chile by César Villarroel from ExploraSub, can be viewed at https://vimeo.com/129499857

PROJECT FUNDING

The project was supported by the Systematics Research Fund (Linnean Society of London and the Systematics Association), the Home for Innovative Researchers and Academic Knowledge Users “HIRAKU” (Hiroshima University), and the NZ National Institute of Water and Atmospheric Research Ltd. Core Funded Coasts & Oceans Programme 2. But mostly, the project relied on in-kind support from a large number of organisations and people, including Australian Fisheries Management Authority, New Zealand Marine Ministry of Primary Industries, New Zealand Department of Conservation, Sanford Limited (New Zealand), University of Otago, New Zealand, National Institute of Water and Atmospheric Research (New Zealand), all natural history museums across New Zealand and Australia, Museo Nacional de Historia Natural, Chile, Naturalis Biodiversity Center (The Netherlands) as well as help from members of the public, including Dr. Joana Browne, Ian Robertson (†), Roscoe Le Compte, Ken and Grace Logan, Melanie Hiller, James McKibbin and many others.

Preparation of the holotype was done by Wellington Museum Te Papa Tongarewa, where it is now housed as the official representative of its species.

You can read further information on this exciting discovery in The Conversationhttps://theconversation.com/the-four-year-treasure-hunt-for-the-hoodwinker-sunfish-81265

For further information on ocean sunfish research at Murdoch University, visit http://thebalisunfish.wixsite.com, or follow us on www.facebook.com/SunfishResearch.

Lars Bejder PhD
Lars Bejder PhD
Professor Lars Bejder PhD is the Research Leader of the Murdoch University Cetacean Research Unit.
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