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New coral treasures from the deep-sea discovered off New Zealand

New coral treasures from the deep-sea discovered off New Zealand

Scientists have recently discovered two new species of bamboo corals from the Southern Pacific Region. These species are known to thrive in depths greater than a thousand meters and their colonies can grow to over a meter in height.
Molecular techniques such as DNA sequencing are important methods in helping to identify species, particularly those that are somewhat “cryptic” and difficult to distinguish visually. Molecular methods have been applied recently to two new bamboo octocorals Keratoisis magnifica and K. peara, two species recently discovered on undersea features such as seamounts, in New Zealand waters.
 

“There are many species of octocoral yet undescribed in the deep-sea but to make sure they are truly new requires a lot of research” said Phil Alderslade, co-author of the discovery and octocoral expert based in CSIRO Hobart, Tasmania, Australia. The taxonomy of octocorals is probably the most intricate and difficult among all corals. Octocorals, with over two thousand known species, have colonized all marine environments from shallow-water to depths greater than five thousand meters and from tropical reefs to Arctic and Antarctic waters.

 

Bamboo corals (family Isididae) are the most calcified octocorals. They owe their name to their resemblance to bamboo stems as they display alternating dark proteinaceous nodes and white calcareous internodes. The calcareous component has been the topic of several medical studies given a similar composition to human bone, and grafts from the corals have been proven to aid in bone healing. Their skeletons have been aged by counting and validating the growth zones that form like tree rings, with maximum ages  >100 years. Given their longevity the skeletons have also been used as proxies for studies on ocean chemistry and climate variation.

 

Skeleton of Keratoisis magnifica (NIWA Invertebrate Collection, Wellington, New Zealand)

“The two new species reported on in this study have visibly distinct morphological characters: one has curved branches and volcano-shaped polyps and the other has a remarkable pearly luster on the skeleton” confirms Luisa Dueñas first author of the paper and doctoral student at the joint program from the University of the Andes in Bogotá, Colombia and Justus-Liebig-Universität-Gießen, Germany. The unique pearl-like skeleton has not previously been observed in bamboo corals, hence the Maori name ‘peara’ for K. peara, to highlight ‘this beautiful feature’ says Luisa.

 

The authors have studied the morphology and DNA sequences for most of the large bamboo corals sampled in New Zealand waters and the description of the two new Keratoisis species was recently published in the journal Molecular Phylogenetics and Evolution.  “We had evidence on the uniqueness of the bamboo corals in the region and our first surprise after the results of the molecular analysis was how many more species might there be as most South Pacific bamboo corals remain undescribed” revealed Juan Sánchez, coauthor of the study and professor at University of the Andes. The authors recognize that this is a first step towards describing this diverse group. It is very difficult to obtain coral specimens from the deep-sea and it is ideal to have several specimens to obtain a clear picture of their biodiversity and interrelationships.

 

The National Institute of Water and Atmospheric Research Ltd. (NIWA), Wellington, New Zealand Invertebrate Collection holds one the largest deep-sea samples specimens of corals  - and invertebrates in general. This unique collection is a treasure of deep-sea biodiversity that regularly attracts many coral experts from around the world.  “We have been gathering deep-sea coral specimens around New Zealand and in Antarctic waters as part of our ongoing exploration and research programs often on behalf of various New Zealand government agencies and we are committed to support molecular and morphological studies on our regional fauna” said Di Tracey, deepsea biologist (NIWA).

 

Dueñas, L., Alderslade P. & J. A. Sánchez (2014) Molecular systematics of the deep-sea bamboo corals (Octocorallia: Isididae: Keratoisidinae) from New Zealand with descriptions of two new species of Keratoisis. Molecular Phylogenetics and Evolution http://dx.doi.org/10.1016/j.ympev.2014.01.031
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