On Sunfish

On 11 July 2020 Gabby Bowran reported a Sunfish washed up on Quarry Beach.  I didn't visit that specimen as we were in Canberra at that time.  I included a reference to that post in the iNaturalist.org discussion which is the main focus of this post and was advised that it was the same species but a different fish.

The substantive element of this post was catalysed by a post to the Mallacoota Community News on 18 July by Shanna McMahon about another Sunfish washed up on Tip Beach.  The two sites are shown in this image.

I went to check it out at about 12 noon (misjudging which end of the beach it was so trekked from Bastion Breakwater).

I posted that photograph to iNaturalist.org to get it into the scientific record.  The first response was from @rfoster (an ichthyologist at the South Australian Museum) explaining that the image didn't show enough detail to identify the fish to species (he rated it as Mola sp.

The key details needed to get it to species were :

1. a close-up of the tail;
2. profile shot of the head; and
3. close up of the scales behind the pectoral fin.

I had a photo showing the tail area ...

.. which was good enough for rfoster to name it as a Hoodwinker Sunfish Mola tecta.  The crucial element is a gap in the fins.  I was also able to confirm this with tail shots from Shanna's post ..

.. and a photo sent later by Judy Mays.

I went back on the morning of 19 July to get some samples for DNA analysis but the fish had been washed out to sea by the high tide.  Fortunately another observer had taken some samples on the 18th and they will be analysed by the Museum of Victoria to thoroughly resolve the identity etc of the specimen.  Hopefully I will be  able to update this post with the results of that analysis.

The reason this is exciting is that the species was only described to science in 2014.  This is described in a Conversation article by the scientist concerned.  Interestingly she comments that "We've found them all around New Zealand (mostly around the South Island), off Tasmania, South Australia, Victoria and New South Wales (Australia), South Africa and southern Chile."  There are only 2 records for Molo tecta in iNaturalist for Australia (this one and one other from Kangaroo Island in 1991 submitted by @rfoster in 2018).  Of the other 24 iNaturalist records most come from NZ or California.

I originally said "There are no records for Molo tecta in the Atlas of Living Australia.. " but in correspondence with ALA have found that there are a few records of Museum specimens there: see this summary.  The problem is that the taxonomy used by ALA doesn't include Molo tecta (showing these records with the Genus name (Molo) but there is text indicating "Hoodwinker Sunfish" as the originally provided common name.  One of the records is from 1873!!!!  I hate taxonomy!

There are also lags in getting iNaturalist records in to the Atlas and hopefully that is the explanation for the listing in iNaturalist from Kangaroo Island not being there.  The Museum specimens come from a range of sites close(ish) to Melbourne.