Two hundred and sixty-six invertebrate species collected in 2012 as part of a Marine Biodiversity Hub survey at Oceanic Shoals Commonwealth Marine Reserve are taking a varied and cosmopolitan route to recognition. The crab species alone have picked up ‘taxonomy miles’ from Melbourne, Brazil, Singapore and New Caledonia, and benefited from an international internship, and a full revision of the genus Maja.

Xanthid crabs from the collection were identified by University of Melbourne Brazilian exchange student Tammy Iwasa-Arai, supervised by Anna McCallum and Joanne Taylor at Museum Victoria. Xanthid crabs are diverse and abundant in tropical shallow water environments, and Tammy identified nine different species, two previously unrecorded in Australia. One may be a new species due its unusual carapace, but only one juvenile male crab was collected, so it’s difficult to be sure. Tammy has carefully described its morphology in the hope that future surveys may recover further samples.

‘I received a scholarship from the Brazilian government to study abroad, and as I was already working with crustaceans in Brazil, I asked for an internship to work on invertebrates at Museum Victoria,’ Tammy says. ‘The family Xanthidae is very complex and none of the samples that I worked on had previously been identified, so we did not know if there were new species or new range extensions for existing species. It was my first taxonomic work with crabs, and it took me six months. I was very excited to describe a potential new species of xanthid.'

Tammy is now doing her Masters research at the National Museum in Rio de Janeiro on the systematics of cyamid whale-lice from the Southern Ocean.

New spider crab named after Hub founding member

A new species of spider crab from Oceanic Shoals, Holthuija poorei, emerged from a three-year revision of the spider crab genus Maja. The revision was led by Peter Ng of Lee Kong Chian Natural History Museum, National University of Singapore, and new Caledonia-based Bertrand Richer de Forges, a research affiliate with Muséum National d'Histoire Naturelle.

Peter and Bertrand borrowed the samples after noticing some ‘odd’ crabs on a voyage collection checklist published by Marine Biodiversity Hub founding member and former Biocurator of Crustacea at Museum Victoria, Gary Poore (after whom the new species is named). Peter says the ‘crab people’ have an outstanding international network.

‘We collaborate effectively across many fronts through exchange of information, sharing of data and specimens etc,’ he says. ‘There are an awful lot of crabs out there – more than 7000 living species – and we are still discovering them at some 50–60 a year on average so there remains much to do.’

Peter says the whole project to revise the Maja genus started innocuously, but looking back they agreed in was one of the nicest papers they had done in their 25-year collaborative career. ‘Bertrand and I were identifying Maja crabs sent to us from the Indian Ocean,’ he says. We began comparing them with extensive collections in my museum (The Lee Kong Chian Natural History Museum, formerly Raffles Museum) from Philippines and Japan. Before we knew it, we were on the road to a full revision to the genus.

‘We initially thought this was a stupid decision as the genus was large with many species stretching from the Atlantic to the Pacific, and complexities that have confused many of our predecessors. There were many old names to check and many historical messes. But with extensive material on hand, help from loans by many colleagues (such as Gary Poore), we cracked the problem in about three years.

‘We found that once we had cleared the ‘debris’ associated with history, the answers were relatively obvious! As a result of these discoveries, we separated Maja into 10 genera (seven of which are new) and recognised 36 species (17 species new). This included two further new species from the Museum Victoria collection: Sakaija longispinosa and Holthuija aussie.’

Further reading

Tammy Iwasa-arai, Anna W Mccallum, and Joanne Taylor (2015) Oceanic Shoals Commonwealth Marine Reserve survey reveals new records of xanthid crabs (Crustacea: Brachyura: Xanthidae) from northern Australia. http://www.nespmarine.edu.au/node/2557

Peter K L Ng and Bertrand Richer De Forges (2015) Revision of the spider crab genus Maja Lamarck, 1801 (Crustacea: Brachyura: Majoidea: Majidae), with descriptions of seven new genera and 17 new species from the Atlantic and Indo-West Pacific. http://lkcnhm.nus.edu.sg/nus/images/data/raffles_bulletin_of_zoology/vol...

Captions

Taxonomist Tammy Iwasa Arai at the National Museum in Rio.

The xanthid crab C. Euxanthus sp., a probable new species from Oceanic Shoals Commonwealth Marine Reserve. Image: Museum Victoria

C. Euxanthus sp (C) among other xanthid species. Images: T. Iwasa-Arai.