Tag: Anthozoa

Three new species of zoantharians described from coral reefs across the Indo-Pacific

One of them was named after the president of Palau, Tommy Remengesau, in honour of his and the nation’s support to the authors and marine conservation

Three new species of zoantharians were discovered by researchers from the University of the Ryukyus and Kagoshima University, Japan, and the Palau International Coral Reef Center. Despite not being previously known, all three species were found widely across the Indo-Pacific, with at least two species found in the Red Sea, the Maldives, Palau, and southern Japan.

Zoantharians, or colonial anemones, include species popular in the pet trade such as Zoanthus or Palythoa, but the new species are all much more cryptic, living in marine caves, cracks, or at depths below most recreational SCUBA diving (>20 m). The research was published December 29, 2017, in the open-access journal ZooKeys.

The three new species belong to the genus Antipathozoanthus, which contains species that only live on top of black coral colonies. However, surprisingly, one of the new species does not live on black corals, but instead in narrow cracks in coral reefs.

“We think that the new species, Antipathozoanthus obscurus, has evolved away from needing to be on top of black corals to take advantage of the available space in coral reef cracks”, said lead researcher Hiroki Kise.

“This is yet another example of how much diversity is right underneath our noses, but we still know nothing about it.”

Coral reefs, which are widely threatened by rising temperatures from global warming, are generally believed to harbour very high numbers of species, including yet many undescribed or unknown species.

Amongst the other two new species is Antipathozoanthus remengesaui, named after the current president of Palau, Tommy Remengesau.

“Much of our work was based in Palau”, said senior author Dr. James Reimer, “and we wished to acknowledge the fantastic support we have received from the nation. Palau is considered at the forefront of marine conservation, and much of this is thanks to President Remengesau’s vision.”

While the new discoveries shed more light on our understanding of coral reef biodiversity, this work is far from done. In fact, the researchers themselves estimate they still have up to ten more zoantharian species to describe from the waters of Palau and Okinawa.

“Marine diversity of coral reefs is amazing, with new surprises all the time”, said Kise, “and biodiversity scientists still have a lot more work to do.”

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Original source:

Kise H, Fujii T, Masucci GD, Biondi P, Reimer JD (2017) Three new species and the molecular phylogeny of Antipathozoanthus from the Indo-Pacific Ocean (Anthozoa, Hexacorallia, Zoantharia). ZooKeys 725: 97-122. https://doi.org/10.3897/zookeys.725.21006

Unusual new zoantharian species is the first described solitary species in over 100 years

A very unusual new species of zoantharian surprised Drs Takuma Fujii and James Davis Reimer, affiliated with Kagoshima University and University of the Ryukyus.

The scientists stumbled upon a solitary individual polyp while conducting SCUBA surveys around the southern Japanese island of Okinawa. They noticed that the creatures were buried almost completely in the soft sediment of the seafloor. It was only their oral disks and tentacles that were protruding above the surface.

Generally, most known zoantharians are colonial (hence their common name of ‘colonial anemones’), and many dwell in shallow waters of subtropical and tropical regions, where their large colonies can be found on coral reefs.

However, these newly discovered polyps were not only leading solitary lives. They were also found to lack zooxanthellae, single-celled organisms that coexist in symbiosis with certain marine invertebrates, also typical for the majority of zoantharians.

The discovery of this unusual new species is reported in the open access journal ZooKeys.

Solitary zoantharian species, such as this one, are known from scant few reports, and only three species are described, all reported more than 100 years ago from the Indo-Pacific region. Overall, very little is known about the hereby studied genus Sphenopus.

The new species, named Sphenopus exilis, is much smaller than the other three Sphenopus species, with its polyps measuring approximately 3 cm in length. It is currently only known from two bays on the east coast of Okinawa Island.

Both of the bays where Sphenopus exilis is found are threatened by development, with one of the bays currently the center of controversy over a proposed American military base expansion and landfill.

“This report demonstrates how much more research is needed on these understudied ecosystems”, stated lead author Dr. Takuma Fujii.

“The only reason this species was discovered was that the right person was in the right place at the right time”, added co-author Dr. James Reimer.

“Such research also shows how important it is to have specialist researchers participate in surveys — otherwise, we might be missing a lot of the biodiversity present in the marine realm simply because we don’t know what we are looking at,” he concluded.

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Original source:

Fujii T, Reimer JD (2016) A new solitary free-living species of the genus Sphenopus (Cnidaria, Anthozoa, Zoantharia, Sphenopidae) from Okinawa-jima Island, Japan. ZooKeys 606: 11-24. doi: 10.3897/zookeys.606.9310

Two new zoantharian species found on eunicid worms in the dark in the Indo-Pacific ocean

While studying the abundant, yet poorly known fauna of the zoantharian Epizoanthus genus in the Indo-Pacific Ocean, Japanese graduate student Hiroki Kise and Dr. James Davis Reimer, both affiliated with University of the Ryukyus, Japan, focused on examining the species living on eunicid worm tubes. These Epizoanthus species form colonies and are only found living on the outside surfaces of tubes in which the eunicid worms live. Although these zoantharians often live in areas that are deeper than the range of SCUBA divers and tend to be indistinguishable on the outside, the present research, published in the open-access journal ZooKeys, reports the discovery of two new species.

Both new species have been found in low-light environments. While one of the species, scientifically named Epizoanthus inazuma, showed preference for coral reef slopes, reef floors, or the sides of their overhangs in Okinawa, the other one, E. beriber was seen to tolerate cave environments exclusively, and is found in Palau and Papua New Guinea. To recognise them as new species, the researchers turned to molecular analyses combined and compared to morphological data. Thus, this discovery presents yet another example of the utility of molecular methods as an effective tool in taxonomic and biodiversity research.

Forming colonies resembling a classic lightning-bolt shape, the new species Epizoanthus inazuma has reasonably been given a name meaning ‘lightning’ in Japanese. The second new species is also named in a reference to its lifestyle as it bears the name of the local Palauan folklore character Beriber, who lived in a cave.

The researchers believe that it is highly likely that there are other undescribed species in coral reefs. There is even greater likelihood that such are currently hidden in underwater cave habitats. The authors do not exclude the possibility that these new zoantharian species may be distributed across other locations in the Pacific, where they could easily be mistaken for other closely related species.

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Original source:

Kise H, Reimer JD (2016) Unexpected diversity and a new species of Epizoanthus (Anthozoa, Hexacorallia) attached to eunicid worm tubes from the Pacific Ocean. ZooKeys 562: 49-71. doi: 10.3897/zookeys.562.6181