Tuesday, May 30, 2017

[Cnidaria • 2017] Sinularia mesophotica • Search for Mesophotic Octocorals (Cnidaria, Anthozoa) and Their Phylogeny. II. A New Zooxanthellate Species from Eilat, northern Red Sea


Sinularia mesophotica 
Benayahu, McFadden, Shoham & van Ofwegen, 2017   


Abstract
An octocoral survey conducted in the mesophotic coral ecosystem (MCE) of Eilat (Gulf of Aqaba, northern Red Sea) yielded a new species of the speciose reef-dwelling genus Sinularia. It features encrusting colony morphology with a thin, funnel-shaped polypary. Sinularia mesophotica sp. n. (family Alcyoniidae) is described and compared to the other congeners with similar morphology. Both the morphological and molecular examination justified the establishment of the new species, also assigning it to a new genetic clade within Sinularia. The results highlight its unique phylogenetic position within the genus, and this is the first described species of a mesophotic zooxanthellate octocoral.

Keywords: Octocorallia, taxonomy, new species, mesophotic coral ecosystem, Eilat, Red Sea

Figure 4. Underwater photographs of Sinularia mesophotica sp. n. A patch of colonies 

Systematic description

Order Alcyonacea Lamouroux, 1912
Family Alcyoniidae Lamouroux, 1912

Genus Sinularia May, 1898

Sinularia mesophotica sp. n.

Figure 1. Sinularia mesophotica sp. n.; A Holotype ZMTAU Co 37425 B paratypes ZMTAU Co 37492.
Scale bar: 1 cm (A also applies to B). 

Diagnosis: The holotype is part of an encrusting colony with a thin, funnel-shaped polypary, also featuring a curly margin (Fig. 1A). In a side-view its maximum dimensions are 5 × 2.5 cm. Polyps with tentacle rods and collaret sclerites (Fig. 2A–C). Tentacle rods up to 0.10 mm long (Fig. 2A). Collaret consists of almost straight spindles, up to 0.20 mm long (Fig. 2B), and shorter bent ones, up to 0.14 mm long (Fig. 2C). Surface layer of the polypary with clubs (Fig. 2D), some featuring a central wart, while in others it is less discernible, or even absent. Clubs vary from 0.10 mm long to 0.25 mm long, and a few with poorly developed heads attain 0.27 mm (Fig. 2E). Surface layer of the colony base contains clubs up to 0.22 mm; some similar to those of polypary, and others have wide heads (Fig. 3A). Polypary and base interior bear spindles, some branched, up to 3.2 mm long (Fig. 3B), with well-spaced simple tubercles (Fig. 3C).

Etymology: The new species name reflects its mesophotic habitat.

Figure 4. Underwater photographs of Sinularia mesophotica sp. n.  B funnel-shaped morphology of colonies. 




Yehuda Benayahu, Catherine S. McFadden, Erez Shoham and Leen P. van Ofwegen. 2017. Search for Mesophotic Octocorals (Cnidaria, Anthozoa) and Their Phylogeny. II. A New Zooxanthellate Species from Eilat, northern Red Sea. ZooKeys. 676: 1-12.  DOI:  10.3897/zookeys.676.12751
  

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