Eleutherobia imaharai, Bryce, Monika, Poliseno, Angelo, Alderslade, Philip & Vargas, Sergio, 2015

Bryce, Monika, Poliseno, Angelo, Alderslade, Philip & Vargas, Sergio, 2015, Digitate and capitate soft corals (Cnidaria: Octocorallia: Alcyoniidae) from Western Australia with reports on new species and new Australian geographical records, Zootaxa 3963 (2), pp. 160-200 : 171-175

publication ID	https://doi.org/ 10.11646/zootaxa.3963.2.2
publication LSID	lsid:zoobank.org:pub:86A305B7-2B9C-403E-8FC0-3420EFB13F52
DOI	https://doi.org/10.5281/zenodo.5680254
persistent identifier	https://treatment.plazi.org/id/03B687F9-A454-FFE9-17DB-50C04EB0FAFA
treatment provided by	Plazi
scientific name	Eleutherobia imaharai
status	sp. nov.

Treatment

Eleutherobia imaharai View in CoL sp. nov.

( Figs. 7 View FIGURE 7. A – C D; 10, 11; Tabs. 1, 2)

Material examined. WAM Z13252 View Materials , one whole specimen, Station 1031302, North West Cape, 190 km north west of Dampier, NW Australia, 21.2802° S, 114.0606° E, epibenthic sled, depth 200–250 m, coll. AIMS NW Cape survey, 13 March 2001.

Description. The colony is essentially two digitiform lobes with an irregular surface, arising from a common base, each slightly tapering to a rounded summit ( Fig 7 View FIGURE 7. A – C D). The largest lobe is about 4 mm wide at its base and projects 16 mm above the holdfast, and the smaller lobe extends 3 mm from the base of the larger lobe before it bends upwards and extends a further 9 mm. The aspect of the holdfast seen in Fig. 7 View FIGURE 7. A – C D is about 15 mm wide. Apart from the holdfast, the numerous monomorphic polyps are evenly distributed over most of the colony, and they are all retracted within low to moderate coenenchymal mounds.

In the surface of the polyparium the sclerites include spindles, up to 0.29 mm long, with acute ends, and ovals 0.08–0.16 mm long; some of latter may have very large, complex warts and one or two sharply tapering ends ( Fig. 10 View FIGURE 10 A). The sclerites of the interior of the polyparium are markedly narrow, acute spindles 0.20–0.40 mm long ( Fig. 10 View FIGURE 10 B).

The polyp armature is formed of slightly curved spindles 0.20–0.55 mm long ( Fig. 10 View FIGURE 10 C). The collaret is about eight to ten rows deep and the points contain five to six pairs of obliquely arranged sclerites. The tentacles contain densely packed rods with a curved end ( Fig. 10 View FIGURE 10 D). They are up to 0.30 mm long, their length becoming smaller towards the tentacle tip, and they are obliquely arranged in two rows covering the aboral and lateral faces of the tentacles ( Fig. 10 View FIGURE 10 F). The pinnules contain a few small spindles, up to 0.12 mm long, with relatively simple tubercles ( Figs. 10 View FIGURE 10 E, F(arrowed)). A few introvert spindles of a similar size and shape as the pinnule sclerites are also present.

The surface of the common base is densely spiculated, mainly with warty ovals, 0.10–0.20 mm long ( Fig. 11 View FIGURE 11 A). Short, plump spindle-like forms, up to 0.25 mm in length, with sharply tapering ends are also present at the surface of the base, as are a few crosses and capstans (see Fig. 11 View FIGURE 11 Aa). The majority of the sclerites in the interior of the common base are spindles up to 0.30 mm long, which commonly have one or both ends acute ( Fig. 11 View FIGURE 11 B). Ovals and a few irregular forms of similar size, that may have pointed processes, also occur.

Colour. The preserved colony has a cream interior and exterior and the sclerites are colourless.

Habitat. The specimens were sampled from a muddy-rubble environment between 200–250 m depth along the continental slope utilising an epibenthic sled.

Remarks. The sclerites of the surface and interior of the new species are of the same form as those of Eleutherobia dofleini as described and illustrated by Verseveldt & Bayer (1988: 29, Figs. 19 View FIGURE 19 , 20 View FIGURE 20 ), by Imahara et al. (2014: 89, Figs. 24, 25) in their new book on the octocorals of Sagami Bay, and to a lesser extent by Utinomi (1954: 45, Fig. 2 View FIGURE 2. A, B ) when describing colonies collected off Minabe. However, the colony form of E. dofleini , which is only known from Sagami Bay to Tosa Bay, Japan, is quite different to that of the new species, having a narrow, commonly branched polypary that generally has pronounced polyp mounds of sufficient size to be termed “Kelche” or “Polypenkelche” by Kükenthal and “calyces” by Imahara et al. and Verseveldt & Bayer. There is also a difference in the polyp body armature of the new species. The latter lacks any intermediate sclerites between the points while E. dofleini has two ( Verseveldt & Bayer 1988: Fig. 20 View FIGURE 20 A1).

In order to check the exact nature of the sclerites from the tentacles and the interior of the polypary in E. dofleini , neither of which were figured by Verseveldt & Bayer, we approached Dr Leen van Ofwegen, the Naturalis Biodiversity Center, Leiden and Dr Yukimitsu Imahara, Biological Institute of Kuroshio, for assistance. Dr van Ofwegen kindly examined the microscope slides used by Verseveldt and Bayer (1988) but found that there were no preparations present of either character. Dr Imahara examined Utinomi’s specimen of E.dofleini from Tanabe Bay, Kii Pininsula, Japan ( Utinomi 1960) and found that the tentacles contain small, somewhat scale-like, curved, flattened spindles with scalloped edges and not curved bars as in the tentacles of the new species, and that the sclerites of the interior of the polypary are not at all long and thin but are shorter and somewhat stouter, like those illustrated in Fig. 25C of the new book on Sagami Bay ( Imahara et al. 2014). He also confirmed the difference in colony form by sending an image of colony ZMB 6524 labelled “ Nidalia dofleini Kük. Type ” (see Fig. 7 View FIGURE 7. A – C E) and added the information that the pinnule sclerites of a colony from Tanabe Bay used by Utinomi (1960) are slender rods that are quite unlike those of the new species.

Etymology. It is with pleasure that we name this new species after our colleague, Dr Yukimitsu Imahara, in recognition of his assistance with our enquiries regarding E. dofleini , his continuing work on Japanese octocorals, and especially the publication (with Drs Fumihito Iwase & Hiroshi Namikawa) of the extremely valuable book on the Sagami Bay representatives of this faunal group.