August 2022 Shikoku and Kyushu

Author: Andrew Baird

In August I had the pleasure and privilege of diving with Dr. Takuma Mezaki of the Kuroshio Biological Research Institute on the rocky reefs of Misaki, Japan. The area is the type location for a number of nominal coral species, including Lobophyllia robusta Veron 1990 and Cyphastrea japonica Yabe & Sugiyama, 1932 but the area is also home to many other sub-tropical and temperate coral species that I was looking for as part of my JSPS fellowship, such as Acropora tanegashimensis Veron 1990, A. japonica Veron 2000 and Micromussa amakusensis (Veron 1990).

Dr. Mezaki is a legend of Japanese coral reef science. He is justly famous for his hundreds of hours diving at night to document the time of spawning for most of the 80 odd species found in Misaki. Dr. Mezaki has been diving these reefs for 20 years and knows them like the back of his hand. Within 2 hours, he had directed me to all the species I was after and much more. The corals in Misaki grow directly on the rocky substratum – there is no coral reef here. Underwater, it looks a lot like the Solitary Islands in northern New South Wales, Australia. Indeed, some of the corals look remarkably similar and that is how they have been interpreted, with some species that are rare in the tropics, such as Acropora solitaryensis Veron & Wallace 1984 and A. glauca (Brook 1893) thought to be common at both sites on opposite side of the equator. I am not so sure. For example, if colonies of A. solitaryensis in the Solitary Islands were placed beside colonies of A. solitaryensis from Misaki, I doubt anyone would think they were the same species; while they do share a similar gross morphology that we call anastomosing-tabular, the colour is very different, the branches have a different shape and seem more widely spaced in the Misaki morph. However, the shape of the radials in the bleached skeletons is very similar (Fig. 1). This is one example of where we definitely need more lines of evidence to decide whether these are one or two species. Time, and the molecules, will tell. 

Figure 1. Acropora solitaryensis. (a-c) our topotype from the Solitary Islands and (d-f) a colony from Misaki, Shukoku, Japan.
Photo credit: Andrew Baird

Dr. Mezaki and his colleagues recognise that many of these species have been misinterpreted and also that many of the species here are new to science. For example, Dr. Mezaki and colleagues believe that there are at least seven new Montipora species to be described from the area. An interesting aspect of Japanese coral reef science is that there are common names for most species, whereas in Australia we have common names for only a handful of species. For example, Figure 2 is a species commonly called Acropora ‘TAIHAI’ which is almost certainly new to science. This means researchers can communicate about these species now rather than waiting for formal taxonomic descriptions which can take time. This is a practise I recommend we adopt in Australia.

Project Phoenix thanks Dr. Mezaki and the Kuroshio Biological Research Institute for hosting Prof. Baird’s visit and helping to collect the corals, and Dr. Yuji Ise for his great company. 

Figure 2Acropora ‘TAIHAI’, common in Misaki and almost certainly new to science.
Photo credit: Andrew Baird

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