Research Article |
Corresponding author: Yehuda Benayahu ( yehudab@tauex.tau.ac.il ) Academic editor: James Reimer
© 2017 Yehuda Benayahu, Catherine S. McFadden, Erez Shoham, Leen P. van Ofwegen.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Benayahu Y, McFadden CS, Shoham E, van Ofwegen LP (2017) Search for mesophotic octocorals (Cnidaria, Anthozoa) and their phylogeny. II. A new zooxanthellate species from Eilat, northern Red Sea. ZooKeys 676: 1-12. https://doi.org/10.3897/zookeys.676.12751
|
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.
Octocorallia , taxonomy, new species, mesophotic coral ecosystem, Eilat, Red Sea
The taxonomy of the northern Red Sea octocorals has been quite extensively studied, albeit mostly confined to the reefs above 30 m (references in
Samples were collected by ROV (ECA H800) operated by the Sam Rothberg R/V of the Interuniversity Institute for Marine Sciences in Eilat. In-situ photography was carried out using a low light black and white camera VS300 (Eca Robotics) and 1CAM Alpha HD camera (SubCimaging). Samples were obtained using the ROV arm. Colony fragments were removed and preserved in 100% ethanol for molecular work. The original samples were placed in 70% ethanol for taxonomic identification, for which sclerites from different parts of the colonies (polyp, polypary surface and interior, base surface and interior) were obtained by dissolving the tissues in 10% sodium hypochlorite, followed by rinsing in fresh water. Sclerites were then prepared for scanning electron microscopy as follows: rinsed with double-distilled water; dried at room temperature, coated with gold-palladium; and examined with a SEM Jeol 6480LV electron microscope and at high vacuum under an environmental scanning electron microscope (ESEM, JSM-6700 Field Emission Scanning Electron Microscope, operated at 10 kV). Wet preparations of tissue smears were examined under a light microscope (X 200) in order to verify presence of symbiotic algae (zooxanthellae). Material studied is deposited at the Steinhardt Museum of Natural History, National Center for Biodiversity Studies, Tel Aviv University, Israel (
DNA was extracted from the EtOH-preserved samples, and two mitochondrial gene regions (mtMutS, igr1 + COI) were sequenced using previously published primers and protocols (
Holotype:
The holotype is part of an encrusting colony with a thin, funnel-shaped polypary, also featuring a curly margin (Fig.
The ethanol-preserved holotype is beige.
The new species name reflects its mesophotic habitat.
Colonies grow as dense patches over reefal-calcareous substrate. Their polypary is flat and horizontally oriented (Fig.
Phylogenetic analyses of mtMutS, igr1 + COI (not shown) and the concatenated sequence (Fig.
Maximum likelihood tree of concatenated mtMutS and igr1+COI mitochondrial gene sequences. Clade numbering system follows
Prior to the present study two Sinularia species have been described as possessing a distinct funnel-shaped polypary. Certain morphologies of S. brassica May, 1898, originally assigned to S. dura (
The holotype of Sinularia lamellata Verseveldt and Tursch, 1979 features a “thin, plate-like funnel-wall” (see p. 143, plate 6), thus also resembling the colonies of S. mesophotica (this study: Figs
The interior of the polypary has almost straight spindles or slightly bent ones, up to 4.8 mm long (Fig.
A comparison of Sinularia lamellata with S. mesophotica reveals that the club heads of the two species are quite different, as the former feature terminal prominences consisting of closely-packed, pointed, thin spikes (see also
Sinularia frondosa Verseveldt, 1978 also has somewhat similar sclerites, but this species does not have the funnel-shaped polypary. Moreover,
The phylogenetic analyses also support the genetic distinction of Sinularia mesophotica sp. n. from S. brassica, S. lamellata, and all other species of Sinularia for which molecular data are available (Fig.
The five previously recognized clades of Sinularia, as well as distinct subclades within the two large clades 4 and 5, can be distinguished morphologically based on a suite of four primary morphological characters. These include the presence of sclerites in the (a) tentacles, (b) collaret, and (c) points regions of the polyp, as well as (d) the shape of the club sclerites in the colony surface tissues (
We thank the Interuniversity Institute for Marine Sciences in Eilat (IUI) for the use of the Sam Rothberg R/V and the professional assistance of its crew members. We are indebted to EcoOcean staff members for operating the ROV. We acknowledge M. Weis and R. Liberman for help in the field, A. Gonzalez for laboratory assistance, A. Shlagman for curatorial skills, V. Wexler for digital editing and N. Paz for editorial assistance. This research was supported by the TASCMAR project (Tools and Strategies to access original bioactive compounds from cultivated marine invertebrates and associated symbionts) which received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 634674; and by the Israel Cohen Chair in Environmental Zoology to YB. Collection of animals complied with a permit issued by the Israel Nature and National Parks Protection Authority.