Tuesday, 16 December 2014

A new species of Soft Coral from the Republic of Congo.


Soft Corals (Octocorals) of the genus Alcyonium form encrusting, lobed colonies on shallow rocky surfaces in tropical waters. These Corals typically have brightly coloured polyps, and have supporting skeletons made up of calcareous spindles.

In a paper published in the journal ZooKeys on 10 December 2014, Leen Van Ofwegen of the Naturalis Biodiversity Center in Leiden, Didier Aurelle of Aix Marseille Université and Avignon Université and Stéphane Sartoretto of the French Research Institute for Exploitation of the Sea describe a new species of Soft Coral from offshore waters of the Republic of Congo.

The new species was initially thought to be a member of the genus Alcyonium, but a genetic study revealed it to be separate from the majority of species in the genus, though it is closely related to a group of other species from the west coast of Africa. For this reason a new genus is erected, Complexum, for this and other species from West Africa formerly assigned to Alcyonium. The name Complexum means complex, a reference to the complex tubercles on the spindle elements of the skeletons of this genus. The species is given the specific name pusillum, meaning ‘tiny’ in reference to the size of its colonies.

Complexum pusillum. (A) Point spindles; (B) collaret spindles (C–D) clubs of surface layer (E) spindles of interior. Van Ofwegen et al. (2014).

Complexum pusillum forms tiny lobe-like colonies on rocks 5-20 m deep between the outflow of the Congo River and that of the Kouilou River. This is an area of high turbidity, with a high input of sediment and other material from the river – not an environment usually favoured by Corals. The polyps of the Coral are completely withdrawn, possibly as an adaptation to this high sediment input environment, so that is superficially resembles a Sponge more than a Coral.

General view of a small patch of colonies of Complexum pusillumon rocky bottom at Banc du Conflit, depth 10 m. Van Ofwegen et al. (2014).

See also…

The Abrolhos Bank is an area of the Brazilian continental shelf to the south of Bahia State, noted for its large and rich coral reef fauna and unique...

Zoanthids are unusual Corals with similarities to both the reef-forming calcareous skeleton excreting Scleractinian Corals and the larger, free living Sea Anemones. Most species are colonial, with...
 
Scleractinian Corals first appeared in the fossil record in the Middle Triassic; they are distinct from, but  believed to be related to the Rugose and Tabulate Corals of the Palaeozoic. All modern Corals...

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