Nanalcyon sagamiense Ima 2013, n. gen.
Creators: name: Ima, Yukimitsu
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Cnidaria
Anthozoa
Alcyonacea
Paralcyoniidae
Nanalcyon
Nanalcyon sagamiense

description: <i>Nanalcyon sagamiense</i> n. gen. n. sp. (Japanese name: Mametsubutosaka) (Figs. 1E–K, 6–8) <b>Holotype.</b> NSMT-CoS 119, one colony attached to fragment of dead bivalve shell, collected by R / V <i>Rinkai-Maru</i>, St. 2, about 4.5 km west of Jogashima light, Kanagawa Pref. Japan, 35°07.4'N, 139°33.6'E – 35°07.8'N, 139°33.2'E, 121–156 m deep, on 20 June 2002. <b>Paratypes.</b> NSMT-CoS 120, one colony, collection data same as for holotype. NSMT-CoS 121-1 to 3, three colonies (including a young colony) attached to same small rock, collected by T / V <i>Shin'yo-Maru</i>, St. 2, about 5 km west of Aburatsubo, Kanagawa Pref. Japan, 35°08.3'N, 139°32.9'E – 35°08.3'N, 139°32.7'E, 177– 148 m deep, on 20 Oct., 2002. NSMT-CoS 122, one colony, collection data same as for NSMT-CoS 121. NSMT-CoS 123-1 to 13, 13 colonies, collection data same as for NSMT-CoS 121. NSMT-CoS 124, one colony attached to living brachiopod (Terebratulida), collected by T / V <i>Shin'yo-Maru</i>, St. 10, about 13 km west of Mera, Chiba Pref. Japan, 34°54.8'N, 139°39.7'E – 34°54.8'N, 139°39.9'E, 348– 312 m deep, on 18 Oct., 2003. NSMT-CoS 125-1 &amp; 2, two colonies attached to two small rocks, collected by T / V <i>Shin'yo-Maru</i>, St. 9, about 12 km WNW of Mera, Chiba Pref. Japan, 34°55.5'N, 139°40.2'E – 34°55.4'N, 139°40.5'E, 375– 275 m deep, on 18 Oct., 2003. NSMT-CoS 126-1 &amp; 2, two colonies, collection data same as for NSMT-CoS 125. <b>Etymology.</b> Named for Sagami Bay, where the holotype was collected. <b>Description of holotype.</b> <i>Colony form</i>: Colony small and independent, not connected to other colonies, with polyps almost fully expanded. Colony 11 mm in total height excluding polyps, consisting of upper soft polyparium 2.5 mm long and 2.2 mm wide, and lower slightly tough, cylindrical pedicel, 8.5 mm long and 3.8 mm wide in its lower swollen part and covered with very thin film (Figs. 1E, F). Seven large polyps arising directly from whole surface of dome-shaped common trunk, seven other small polyps surrounding proximal part of trunk. One or two of larger polyps bearing small secondary polyps near proximal part of anthostele (Fig. 1E). Many large spindles visible through thin film of pedicel. Cortex of trunk very thin, and inner layer of both trunk and pedicel provided with only a few very thin canal walls. Many spherical gonads of about 0.5 mm in diameter present in gastric cavities. <i>Polyps</i>: Monomorphic, about 3 mm long excluding tentacles, and 1 mm wide in their swollen anthocodial part (Figs. 1G, 6A). Tentacles about 1 mm long with bilateral rows of six to eight short pinnules each. No sclerites in tentacles except for five to seven somewhat elongated subtentacular platelets, up to 0.140 x 0.025 mm in size, gathered proximally (Figs. 1G, 6A, B, 7A). Below these platelets, 12–14 elongated rods (Figs. 6C, 7C) up to 0.320 x 0.038 mm in size and arranged in chevrons, plus 6–11 transversely arranged rods of same kind (Figs. 1G, 6A). All sclerites consisting of closely set, non-branching, rod-like crystals arranged in oblong parallel rows toward both ends of sclerite (Figs. 7B, 7D). Anthostele entirely devoid of sclerites. <i>Other sclerites</i>: Although most of trunk entirely devoid of sclerites, a few short rods (Figs. 6D, 8A) up to 0.175 x 0.045 mm in size present in cortex of circumference of only some polyps. Cortex of pedicel with long spindles (Fig. 8C) up to 1.500 x 0.216 mm, arranged in almost longitudinal rows; these spindles often curved and sometimes furcate, and covered with many small, complex warts (Fig. 8D). All sclerites consisting of crystals very similar to those of anthocodial elongated rods (Figs. 8B, D). Sclerites absent from inner layer of trunk and pedicel. <i>Color</i>: Trunk and polyps of live colonies are translucent pink with reddish pharynx, and the pedicel is somewhat translucent pale orange. Sclerites almost transparent. In alcohol, the polyparium is pale ivory and the pedicel is dark yellowish-orange, all sclerites are translucent to some degree. <b>Remarks.</b> NSMT-CoS 120, a paratype, is a distinctly contracted cylindrical colony (Fig. 1H), 6.7 mm high and 4.3 m wide at its somewhat swollen middle part. The polyparium is completely withdrawn into the pedicel. The spindles of the cortex of the pedicel are arranged almost in eight chevrons in the upper to middle part of the pedicel, in addition to a few spindles arranged transversely in the middle and proximal parts. NSMT-CoS 121, a paratype, consists of three extremely contracted colonies attached within a space of about one centimeter square on a small stone (Fig. 1I). Two of them are of almost the same size, about 6 mm high and 3.5 mm wide, but the third one is very small, about 0.8 mm high and wide (circled in Fig. 1I). These three colonies each have a more or less expanded basal membrane, but they are not connected to each together by either a basal membrane or stolon. NSMT-CoS 122, a paratype, is a partially expanded colony (Fig. 1J), 8.20 mm in total height, with a polyparium about 0.6 mm high and 4.2 mm wide, and a pedicel about 7.6 mm high and 3.3 mm wide in its upper part and 2.5 mm wide in its lower part, and with a basal membrane about 5.0 mm wide. Several of the primary polyps bear one small proximal secondary polyp each.
description: Published as part of <i>Ima, Yukimitsu, 2013, Two new paralcyoniid octocorals from Japan (Anthozoa: Alcyonacea), pp. 424-436 in Zootaxa 3652 (4)</i> on pages 430-431, DOI: 10.11646/zootaxa.3652.4.2, http://zenodo.org/record/5265248