Melithaea davidi, Samimi-Namin, Kaveh, van Ofwegen, Leen P. & McFadden, Catherine S., 2016

Samimi-Namin, Kaveh, van Ofwegen, Leen P. & McFadden, Catherine S., 2016, A new species of Melithaea (Anthozoa, Octocorallia, Melithaeidae) from the Oman Sea, off Oman, ZooKeys 623, pp. 15-29 : 20-21

Taxon classification Animalia Alcyonacea Melithaeidae

Melithaea davidi sp. n. Figures 3, 4, 5, 6, 7

Material examined.

Holotype: RMNH Coel. 42122, Oman, Oman Sea, 23.654267°N 58.629567°E, 79 m deep on a ship wreck, Robert’s barge, coll. David Mothershaw and Robin Norman, 19 July 2013. Paratypes: RMNH Coel. 42123, RMNH Coel. 42124, same data as holotype.

Description.

The holotype is branching dichotomously in several parallel planes, forming a network with many anastomoses. It is 12 cm high and 9 cm wide (Figure 3). The nodes are larger and more swollen in the basal parts of the colony. Many branches are covered with tiny white ophiuroids.

Polyp mounds and calyces are up to 1 mm in diameter. Calyces are projecting above the coenenchyme and are mostly situated along the sides of the branches. Polyps are situated 1-1.5 mm apart from each other (Figure 3).The coenenchyme has spindles, up to 0.35 mm long, with irregular simple tuberculation (Figure 4A). Additionally, the calyces have clubs, also up to 0.35 mm long, with simple tubercles and leaf-like projections at the distal end (Figure 4B). The calyx sclerites are mostly arranged en chevron. Some of the coenenchymal spindles have leaf-like or spinose side projections (Figure 5). In addition, there are some irregularly shaped sclerites present, up to 0.15 mm long, with or without leaf-like and spinose projections. Capstans are not present in the coenenchyme.

Polyps have two rows of collaret spindles and four spindles per point. The collaret spindles are up to 0.40 mm long, with more tuberculation on the middle of the convex side, and less tuberculation at the distal ends (Figure 6A).

The point sclerites are up to 0.25 mm long, with simple tubercles and projecting spines at the distal end (Figure 6B).

The tentacles contain flattened, dragon-wing shaped sclerites up to 0.15 mm long (Figure 6C).

The pharynx and introvert have small spiny sclerites that are up to 0.05 mm long (Figure 6D).

The nodes and internodes have internal rods and cigar-shaped sclerites up to 0.12 mm long, with or without median whorl of projections (Figure 6E).

Etymology.

The species is named after David Mothershaw who collected the specimens.

Colour.

The holotype is orange-red (Figure 3A). The colour of the nodes in younger parts of the colony is the same as the colony colour but in the older basal parts of the colony, they are brownish. All sclerites are reddish. The live colony had the same colour as the preserved one, with whitish translucent polyps (Figure 7).

Morphological variation.

One paratype (RMNH Coel. 42124) is light pink (Figures 3C, 7B).

Remarks.

The species resembles Melithaea biserialis ( Kükenthal, 1908) and Melithaea sinaica Grasshoff, 2000, both described from the nearby Red Sea. Melithaea biserialis and Melithaea sinaica both have more tuberculate sclerites and, additionally, capstans that are not present at all in Melithaea davidi . The species also resembles Acabaria spec. indet. 2 Ofwegen (1987) from West India. However, that species also has capstans that are absent in Melithaea davidi .

Acabaria indet. 2 Ofwegen (1987) might represent a new species, however, the material is not sufficient for describing a new species.

Acabaria mabahissi Hickson, 1940, off Cape Guardafui, Gulf of Aden, and the Arabian Sea is the same as Acabaria spec. indet. 1 ( Ofwegen 1987) from Somalia and Kenya.

Distribution.

Known only from the type locality.