Every day in labs, museums, out on fieldwork, taxonomists are busy collecting, cataloguing, identifying, comparing, describing and naming species new to science. Some 500 experts globally also contribute their valuable time to keeping the World Register of Marine Species (WoRMS
), and its sub-registers (e.g. WoRCS
), up to date.
All editors of WoRMS and editors of major taxonomy journals were given the opportunity to nominate their favourite marine species in order to create an annual list of the top-ten marine species
described by researchers during the year 2019. Nominated species must have been described between January 1st and December 31st, 2019, and have come from the marine environment (including fossil taxa). A small committee (including both taxonomists and data managers) was brought together to decide upon the final candidates. The list is in no hierarchical order.
The final decisions reflect the immense diversity of animal groups in the marine environment (including fish, crustaceans, molluscs, corals, sponges, jellies, worms) and highlight some of the challenges facing the marine environment today. The final candidates also feature particularly astonishing marine creatures, notable for their interest to both science and the public.
This top-ten list
is just a small highlight of almost 2,000 fascinating new marine species discovered every year and was released on 19 March 2020 to coincide with World Taxonomist Appreciation day.
One cave-dwelling species
, the bioluminescent brittle star Ophiopsila xmasilluminans
Okanishi, Oba & Fujita, 2019 that was recently discovered living in a marine cave on Christmas Island, NW Australia, was included in the 2019 list of the top-ten marine species.
The Christmas-Light Brittle Star
Okanishi, Oba & Fujita, 2019
This unusual new species of brittle star was recently discovered living in a cave ecosystem on Christmas Island, in northwestern Australia. The animal survives in complete darkness and is believed to be endemic to this habitat. The species name ‘xmasilluminans
’ means ‘Christmas lighting’, in reference both to its origin, Christmas Island, and to the flashing light emitted from the arms. The specimens were collected by divers who noted that the arms start flashing as a response to being touched. This response to mechanical stimulation is likely to be a defensive response to predation. Some brittle stars are capable of ‘losing’ an arm to save the rest of the animal and in the case of this species, these severed arms were seen to produce green flashes of light and even to wriggle, which would certainly be an effective distraction to the would-be predator.
Bioluminescence is found in several ophiuroid species, but this is the first, and so far only, cave-living species to show this behavioural adaptation. Cave-dwelling brittle stars are rare and have only recently been studied in detail. We know very little about how they came to live in caves and what their adaptations are to this unusual environment.
- Okanishi, M.; Oba, Y.; Fujita, Y. (2019). Brittle stars from a submarine cave of Christmas Island, northwestern Australia, with description of a new bioluminescent species Ophiopsila xmasilluminans (Echinodermata: Ophiuroidea) and notes on its behaviour. Raffles Bulletin of Zoology 67: 421-439. https://doi.org/10.26107/RBZ-2019-0034