Nanalcyon sagamiense, Ima, 2013

Ima, Yukimitsu, 2013, Two new paralcyoniid octocorals from Japan (Anthozoa: Alcyonacea), Zootaxa 3652 (4), pp. 424-436 : 430-431

publication ID	https://doi.org/ 10.11646/zootaxa.3652.4.2
publication LSID	lsid:zoobank.org:pub:DE01C38B-C11D-4BB2-8A58-2F25F370F2F6
DOI	https://doi.org/10.5281/zenodo.5266694
persistent identifier	https://treatment.plazi.org/id/F317878F-7556-FFAC-A892-04094547C9CD
treatment provided by	Felipe
scientific name	Nanalcyon sagamiense
status	gen. nov.

Treatment

Nanalcyon sagamiense View in CoL n. gen. n. sp. (Japanese name: Mametsubutosaka)

( Figs. 1E–K View FIGURE 1 , 6–8 View FIGURE 6 View FIGURE 7 View FIGURE 8 )

Holotype. NSMT-CoS 119, one colony attached to fragment of dead bivalve shell, collected by R / V Rinkai-Maru , 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. GoogleMaps

Paratypes. 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 Shin'yo-Maru , 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 Shin'yo-Maru , 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 & 2, two colonies attached to two small rocks, collected by T / V Shin'yo-Maru, 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 & 2, two colonies, collection data same as for NSMT-CoS 125 GoogleMaps .

Etymology. Named for Sagami Bay, where the holotype was collected.

Description of holotype. Colony form: 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 View FIGURE 1 ). 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 View FIGURE 1 ). 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.

Polyps: Monomorphic, about 3 mm long excluding tentacles, and 1 mm wide in their swollen anthocodial part ( Figs. 1G View FIGURE 1 , 6A View FIGURE 6 ). 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 View FIGURE 1 , 6A, B View FIGURE 6 , 7A View FIGURE 7 ). Below these platelets, 12–14 elongated rods ( Figs. 6C View FIGURE 6 , 7C View FIGURE 7 ) 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 View FIGURE 1 , 6A View FIGURE 6 ). All sclerites consisting of closely set, non-branching, rod-like crystals arranged in oblong parallel rows toward both ends of sclerite ( Figs. 7B, 7D View FIGURE 7 ). Anthostele entirely devoid of sclerites.

Other sclerites: Although most of trunk entirely devoid of sclerites, a few short rods ( Figs. 6D View FIGURE 6 , 8A View FIGURE 8 ) 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 View FIGURE 8 ) 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 View FIGURE 8 ). All sclerites consisting of crystals very similar to those of anthocodial elongated rods ( Figs. 8B, D View FIGURE 8 ). Sclerites absent from inner layer of trunk and pedicel.

Color: 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.

Remarks. NSMT-CoS 120, a paratype, is a distinctly contracted cylindrical colony ( Fig. 1H View FIGURE 1 ), 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 View FIGURE 1 ). 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 View FIGURE 1 ). 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 View FIGURE 1 ), 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.