Dr Andrew Baird (James Cook University), Dr Tom Bridge (Queensland Museum Tropics), Dr Peter Cowman (Queensland Museum Tropics) and Assoc. Prof Joshua Madin (University of Hawai’i) were awarded a Lizard Island Reef Research Foundation Critical Grant in 2022 to apply an integrated taxonomic approach to document the diversity of stony corals at Lizard Island. Almost 400 samples have been deposited at the Australian Museum and molecular sequencing has been carried out on many of these. The post below describes their findings.
This Critical Research Grant was supported by generous donations from Ian and Min Darling, and Sally White.
The strikingly beautiful corals on the reefs around Lizard Island are changing names.
Coral taxonomy has traditionally been based on the morphology of coral skeletons but adding molecular data to the taxonomists’ tool kit has changed our understanding of species.
Why does this matter?
Taxonomy is the science of naming species and understanding evolutionary relationships. The name of a species is a handle for our knowledge about animals and plants. The name tells us about evolutionary relationships, feeding and reproductive biology, distribution and the roles and place of the species in the reef community. Taxonomists revise the names of species as new information changes our understanding of a species.
The Lizard Island Reef Research Foundation funded a Critical Grants project to investigate the taxonomy of stony corals using molecular analysis, morphology and other data such as reproductive biology and habitat preferences. This is called an ‘integrated approach’ to solving taxonomic questions.
The aim of the project is to establish a curated collection of all scleractinian coral species from Lizard Island, including field and skeleton images plus tissue samples. From this collection, which has been deposited at the Australian Museum, a morpho-species guide to the corals of Lizard Island will be produced and made freely available via the Lizard Island Field Guide. This will allow for consistency in identification of corals among studies.
The team envisages that this will involve the description of numerous new species, and new recognition of species names established in the past. The naming of species follows international rules of nomenclature governed by a code used by all taxonomists. Naming new species and resurrecting old names is the day to day work of taxonomists as new data becomes available and species concepts change.
The research indicates that the species richness in many groups of stony coral is considerably higher than previously recognised, largely due to an extraordinary number of undescribed species that are coming to light with the use of modern integrated approaches, in particular, the use of molecular markers. It is likely that many species have narrower distribution ranges than previously thought.
For example, of the 64 species hypotheses developed from the preliminary analysis of Acropora collected from Lizard Island, it is estimated that 32 are undescribed and a further 16 are species names that have slipped out of use. That means only 16 are names that are found on previous species lists. Therefore, 75 % of the Acropora diversity on Lizard Island is what we call “dark diversity”. Many of the species names commonly used in experiments at Lizard Island Research Station may be incorrect. The species previously identified as A. hyacinthus at Trimodal Reef, Lizard Island is a species complex of at least four species (Figure 1).
Figure 1. Four different species previously identified as Acropora hyacinthus on the reefs of Lizard Island. Only one of these species is likely to be A. hyacinthus (LI-AC019). The other species are either undescribed (LI-AC021; LI-0886) or in synonym (LI-AC018) = A. pectinata
This research suggests that species boundaries, distributions and abundances of species and the biogeographical affinities of the coral fauna of the Great Barrier Reef will need to be revaluated. Previous species lists will be unreliable indicators of historical distributions and the results of research based on earlier taxonomic frameworks will need to be reevaluated.
By Dr Penny Berents, Senior Fellow, Australian Museum Research Institute
Trustee, Lizard Island Reef Research Foundation
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https://lirrf.org/2022-critical-research-grant-awarded/
https://lirrf.org/how-many-coral-species-exist-at-lizard-island/