Australian Museum’s 130-year-old black coral collection reveals hidden Australian biodiversity

Black corals in the Australian Museum represent a treasure trove of biodiversity information – including undescribed species and new species records for Australian waters!

Black corals can be found at great depths, making their collection costly and logistically challenging. For over 130 years, black corals have been collected and deposited in the Australian Museum, resulting in over 200 predominantly unexamined black corals – therefore providing an amazing opportunity to extract biodiversity information about this understudied coral group in Australian waters.

Funded by the 2020-21 AMF/AMRI Visiting Collections Fellowship, Kristina Pahang and I examined the entire black coral collection in the Australian Museum. Some of these specimens have been untouched since they were collected and preserved in ethanol-filled jars for over 100 years!

Examining these specimens over a two-week period has led to significant scientific discoveries including species that have yet to be formally described. For example, Dr Penny Berents from the Australian Museum collected a few colonies in 2003 that have alternating pinnules (branches), suggesting it belongs to the genus Alternatipathes (first noticed by Dr Tina Molodtsova). However, the colonies have relatively short stems for the genus and were collected from shallower depths than expected, suggesting that it is likely a new species and a range expansion for the genus.

This collection demonstrates that there are more black coral species in Australian waters than previously thought. Hiding in this collection are the first Australian records of numerous black coral species. Additionally, Australian waters are home to the most ancient black coral family, the Leiopathidae, individuals of which can live for ~4,000 years and which have been on earth for over 400 million years, surviving through two global mass extinction events!

In terms of future research, many of these specimens will be subject to closer examination including electron microscope scanning of skeletal spines; although microscopic, these are informative features on the skeleton for most species. In addition to SEM images, we will also extract DNA from samples and sequence portions across the genome known as Ultraconserved Elements, which show promise for reconstructing evolutionary relationships and histories.

The Australian Museum collection represents a sample of which species have lived and continue to live in Australian waters. This information (geographic ranges of species, and diversity of species in specific regions) underpins marine conservation decisions, which is why identifying species in museum collections is so important. Continued efforts, including surveying and collecting species from unexplored locations, will allow us to understand and preserve overall biodiversity in Australia.

Jeremy Horowitz, PhD student at the Centre of Excellence for Coral Reef Studies, James Cook University and 2020-21 AMF/AMRI Visiting Collections Fellowship recipient.