Adinisis thresheri, Lapointe & Watling, 2022

Lapointe, Abby & Watling, Les, 2022, Towards a revision of the bamboo corals (Octocorallia): Part 5, new genera and species of Keratoisididae from the Tasmanian deep sea, Zootaxa 5168 (2), pp. 137-157 : 150

Adinisis thresheri new species

Figure 12

Material Examined. Holotype: The Knob, Tasman Fracture Zone, Tasmanian Seamounts , TMAG K3843 , collected on 12 January 2009, -45.1428, 145.9840, 1645 m, 2.56° C bottom temp . Paratypes: TMAG K3853 , The Knob, Tasmanian Seamounts, collected on 12 January 2009, -45.1368, 145.9776, 1813 m . TMAG K3839 , Cascade Plateau, Tasmanian Seamounts, collected on 04 January 2009, -44.0771, 150.3334, 2009 m , 2.34° C bottom temp.

Diagnosis. Colony unbranched, with bends and curves in the axis. Polyps are tall, with numerous scales and long septal sclerites in the form of sharp needles. Scales are more abundant in the basal part of the polyp body, where needles are absent.

Description of Holotype. Colony unbranched, with bends and curves in the axis ( Fig. 12A, B ). The axis is approximately 5 mm in diameter, smooth, with a hollow core occupying roughly 80% of the diameter of the axis. Internodes range from 20 to 80 mm in length.

Polyps are located on all sides of the axis, densely arranged, with small amounts of coenenchyme between polyps. Polyps are tall, columnar, up to 10 mm in height and approximately three times as long as wide, and may be divided into two sections approximately halfway along the length ( Fig. 12C ). The basal section of the polyp body is wider than the distal part, and bears sclerites in the form of numerous small scales and some small rods, arranged randomly.

Large needles are found only between the tentacles. These septally-arranged large individual protruding needles ( Fig. 12D ) may flare outward slightly when the tentacles are contracted ( Fig. 12C ). Smaller needles are arranged between the eight intertentacular sclerites. Sclerites of the coenenchyme, in the form of small scales, similar to the scales found at the base of the polyp body ( Fig. 12E ) are loosely and irregularly arranged. Coenenchyme scales were observed ranging in length from 0.12 to 0.27 mm.

When contracted, tentacles fold slightly inward with tips touching. Sclerites of the tentacles are flat rods, with a heavily textured surface ( Fig. 12F ), ranging in length from 0.059 to 0.225 mm, and may frequently be fused. Sclerites are densely packed throughout the tentacles and are randomly arranged horizontally, diagonally, and longitudinally.

Sclerites of the pharynx are “hedgehogs”, with a heavily textured surface composed of irregular teeth and numerous protuberances ( Fig. 12G ). They are approximately 0.06 mm in length and 0.02 mm in width at their center.

Variation of Paratypes. Needle sclerites in the distal portion of the polyp body, surrounding the tentacles, may frequently be forked or fused. In addition to the numerous scales found in the coenenchyme, small rods, up to approximately 0.3 mm, may also be present. Scales may be irregularly shaped, but usually taper midway along their length. Sclerites in the pharynx may be as large as 0.075 mm.

Etymology. This species is named in honor of Dr. Ronald E. Thresher, the co-chief scientist of the cruise in recognition of his many contributions to our understanding of seamount communities.

Remarks. Adinisis thresheri is characterized by the long polyps and the presence of numerous small scales and needles at the base of the polyp and throughout the coenenchyme. Large needles are only present surrounding the tentacles.

Figures

FIGURE 12. Adinisis thresheri n. sp., holotype, K3843, A, all collected and preserved colony pieces, B, in situ view of colony, C, view of individual polyp, and sclerites of, D, upper part of polyp body, E, lower part of polyp body and coenenchyme, F, tentacles, G, pharynx.