Melithaea boninensis, Matsumoto, Asako K. & van Ofwegen, Leen P., 2015

Matsumoto, Asako K. & van Ofwegen, Leen P., 2015, Melithaeidae of Japan (Octocorallia, Alcyonacea) re-examined with descriptions of 11 new species, ZooKeys 522, pp. 1-127 : 7

Taxon classification Animalia Alcyonacea Melithaeidae

Melithaea boninensis sp. n. Figures 8, 9 b–c, 12, 13

Material examined.

Holotype UMUTZ-CnidG-205, Ogasawara Isls. (= Bonin Isls.), Japan, coll. S. Hirota and Sekiguchi, 11 April 1894; paratype UMUTZ-CnidG-255, same data as holotype.

Description.

The holotype is 8 cm long and 4.5 cm wide, branching is in two parallel planes, and with a holdfast (Fig. 9b). The stem is 5 mm wide, the end branches only 1 mm wide. The colony has many anastomoses. The polyps are situated all around the branches, the calyces are dome-shaped, and the polyps are retracted. Points with slightly bent spindles up to 0.15 mm long, distal end with leaves (Fig. 12a). Collaret with bent spindles up to 0.20 mm long, middle part with more tubercles or side branches (Fig. 12b). Tentacles with platelets, the larger ones crescent-shaped with irregular projections (Fig. 12c). These platelets are up to 0.10 mm long. Pharynx with straight spiny rods, up to 0.05 mm long (Fig. 12d). Coenenchyme with capstans (Fig. 12e), unilaterally foliate spheroids (Fig. 12f), 0.05-0.10 mm long and small clubs of similar length (Fig. 12g); spindles (Fig. 13b) and unilaterally foliate spindles (Fig. 13a) are 0.10-0.20 mm long. The calyces with longer clubs, up to 0.15 mm long (Fig. 12h). Most coenenchymal sclerites have complex tubercles.

Color.

The colony and sclerites are orange.

Distribution.

The species is only known from the Ogasawara Islands (= Bonin Islands) (Fig. 8).

Etymology. The species is named after the type locality, the Bonin Islands.

Remarks.

This is the first record of Melithaea from this island group. The colony shape of paratype UMUTZ-CnidG-255, collected at the same time with G205, looks similar toZ-CnidG-205, but it has disintegrated sclerites. The colony is slightly smaller and brighter orange-colored (Fig. 9c). Its sclerites are similar to those of the holotype. This is the only species that looks like Melithaea habereri ( Kükenthal, 1908), having many anastomoses, but its sclerites are quite different, many with leaves, while Kükenthal described spiny sclerites for Melithaea habereri .