Euplexaura yayoii, Matsumoto, Asako K. & van Ofwegen, Leen P., 2016

Matsumoto, Asako K. & van Ofwegen, Leen P., 2016, Species of Elasmogorgia and Euplexaura (Cnidaria, Octocorallia) from Japan with a discussion about the genus Filigella, ZooKeys 589, pp. 1-21 : 8-9

Taxon classification Animalia Alcyonacea Plexauridae

Euplexaura yayoii sp. n. Figures 1, 2e, 10, 11

Material examined.

Holotype RMNH 42104 (AKM1551), Off Ohako-zaki cape, Otsuchi Bay, Iwate Prefecture, Japan. 142°00.640'E 39°31.400'N, depth 77.0 m, RV Yayoi, st. 4-1, coll. A.K. Matsumoto, 27 April 2010; paratypes RMNH 42105 (AKM592), entrance of Otsuchi Bay, Iwate Prefecture, Japan, 39°21.858'N, 141°59.972'E, depth 65.6 m, RV Yayoi, st. 1, coll. A.K. Matsumoto, 12 September 2005; RMNH 42106 (AKM597), same data as AKM 592; RMNH 42107 (AKM623), off Ohako-zaki cape, Otsuchi Bay, Iwate Prefecture, Japan, 142°00.556'E 39°21.452'N, depth 63 m, RV Yayoi, st. 2, coll. A.K. Matsumoto, 12 September 2005.

Description.

The holotype is 2.5 cm high and 5.5 cm wide (Figure 2e). The colony is branched only once, 1 cm above the base. The two branches are very slender, only 1 mm thick; the calyces are low, dome-shaped, arranged spirally around the branches.

The polyps have points with slightly bent, flattened spindles, up to 0.30 mm long, with a few tubercles and a slightly spiny distal end (Figure 10b). The collaret has bent, flattened spindles, up to 0.30 mm long, with simple tubercles, the largest tubercles present in the middle (Figure 10c). The tentacles have flattened rods, up to 0.15 mm long, with hardly any tubercles (Figure 10a). The surface layer of the branches has spindles and blunt ellipsoids, up to 0.15 mm long, with complex tubercles (Figure 11). The deeper layer has short spindles, up to 0.10 mm long, and a few crosses (Figure 10d-e); all with simple tubercles.

Etymology.

Named after the research vessel that was used to collect the specimens.

Remarks.

The live colony has blue-coloured polyps. Euplexaura yayoii differs from the two other Japanese Euplexaura species with thread-like branches, Euplexaura boninensis and Elasmogorgia mitsukurii , by its very small sclerites.

Distribution.

Otsuchi Bay, Iwate Prefecture, Japan.