Calcigorgia lukini, Dautova, 2019

Dautova, Tatiana N., 2019, New species of deep-water Calcigorgia gorgonians (Anthozoa: Octocorallia) from the Sea of Okhotsk, with a re-diagnosis and a taxonomic review of the genus, European Journal of Taxonomy 549, pp. 1-27 : 14-21

Calcigorgia lukini sp. nov.

urn:lsid:zoobank.org:act:C2373F6E-0EA5-4E4B-804D-772AF1DB0738

Figs 8–12, Table 1

Diagnosis

Calcigorgia colonies scantly branched in several planes, with short smooth stem. Polyps remote from each other, arranged irregularly on surface of the branch, in alcohol-preserved material up to 1.8 mm high and up to 1.8 mm wide. Body walls of polyps with smooth surface; lower parts of polyps slightly widened. Polyp tentacles with warty spindles, poorly developed clubs with leafy processes on head, ovals and 8-radiate capstans. Polyp body walls with 8-radiate capstans and ovals. Both layers of coenenchyme with 8-radiate capstans; outer layer may contain ovals.

Etymology

The specific epithet is given in honor of Dr Vladimir Lukin, enthusiastic researcher of marine biodiversity in the National Scientific Centre of Marine Biology FEB RAS, who made a great collection of invertebrates in the Sea of Okhotsk in the 1980s.

Material examined

Holotype

SEA OF OKHOTSK – Kurile Islands • 95 × 59 mm; Iturup Is.; expedition of PFRC and ZIN RAS on RV Tikhookeansky; 44°38′ N, 146°55′ E; depth 100 m; 28 Sept. 1987; S. Grebelnyi leg.; dredged; MIMB 20710 .

Paratype

SEA OF OKHOTSK – Kurile Islands • 112 × 44 mm; Iturup Is.; expedition of PFRC and ZIN RAS on RV Tikhookeansky; 44°31′ N, 147°06′ E; depth 50 m; 15 Sept. 1987; S. Grebelnyi leg.; dredged; MIMB 20712 .

Additional material

SEA OF OKHOTSK • 1 specimen; Urup Is., Kurile Islands ; 45°54′ N, 149°59′ E; depth 60 m; 12 Oct. 1973; Artemov leg.; dredged; MIMB 20691 • 1 specimen; Shelikhov Bay ; cruise of RV Akademik Oparin; 60°02′ N, 158°24′ E; depth 60 m; 19 Aug. 2008; Nikolay Selin leg.; dredged; MIMB 20743 .

Description

Holotype

Holotype alcohol-preserved colony 95 mm high and 59 mm wide, scantily branched ( Fig. 8A). Side branches flexible, placed irregularly. Polyps up to 1.5 mm high and 2 mm wide, disposed irregularly at distances of 1–2 mm from each other. Tentacles folded over polyp and partly retracted to inside; polyp body smooth and cylindrical in shape ( Fig. 8D).

Coenenchyme 0.8 mm thick, in two layers; a 0.6 mm thick outer layer, with smooth surface; a very thin inner layer, semi-transparent and longitudinally ridged. Axis with concentric layers without any visible mineralization. The axial canal present, but very narrow and hardly visible in the tip of the branches.

Tentacles with warty spindles, poorly developed clubs with a warty handle and leafy processes on head, ovals and capstans. Warty spindles, of irregular shape, branched, mainly 0.17–0.19 mm long, covered by granulated warts ( Fig. 9A). Clubs mainly 0.12–0.19 mm long, sometimes up to 0.20 mm, with a plump head, consisting of several leafy processes ( Fig. 9B). Short handle straight, thick and blunt, densely ornamented with small warts. Some longer clubs, up to 0.2 mm, with poorly developed leafy processes on head and very thick handle, are transitional to asymmetrical warty ovals ( Fig. 9C). These ovals mainly up to 0.19 mm long, ornamented with small crowded warts tending to be conjunct ( Fig. 9C). Symmetrical ovals well calcified, usually up to 0.18–0.19 mm long ( Fig. 9D). Capstans mostly up to 0.18 mm long ( Fig. 9E). These are well-calcified 8-radiate sclerites with two girdles of warts and plump terminal processes.

Numerous capstans (8-radiate) in body wall of polyps, mainly 0.16–0.18 mm long, with plump terminal warts ( Fig. 10A). Well calcified capstans, up to 0.18 mm ( Fig. 10B), transitional to warty ovals. Ovals, mostly 0.16–0.19 mm long, ornamented with warts tending to be conjunct ( Fig. 10C).

Both layers of coenenchyme contain capstans, mostly 0.16–0.19 mm long ( Fig. 10D). These wellcalcified 8-radiate sclerites with two girdles of warts and plump terminal processes. Some capstans, up to 0.13 mm long, less calcified, but with well-formed and girdled warts.

Paratype and variations

Paratype MIMB 20712 colony shape and size similar to the holotype – 112 mm high and 44 mm wide ( Fig. 8B). Polyps up to 1.6 mm high and 2 mm wide, disposed irregularly at distances of 1–2 mm from each other. Sclerites composition ( Figs 11–12) coincides with that in the holotype ( Figs 9–10). The only difference is smaller size of ovals and capstans in the polyp body wall and the coenenchyme of the paratype. Paratype’s ovals shorter in polyp body wall – these mostly up to 0.16 mm long ( Fig. 11 C–D) vs up to 0.19 mm in the holotype ( Figs 9 C–D, 10C). Capstans in coenenchyme of the paratype mostly up to 0.15 mm long ( Fig. 11F) vs up to 0.19 mm in the holotype ( Fig. 10D).

Colour

In alcohol-preserved material: the polyps and coenenchyme creamy or light-brown; the colony axis black or deeply brown; sclerites colourless.

Remarks

Calcigorgia lukini sp. nov. presents a range of characters differing from other known species of the genus.

Polyps of С. lukini sp. nov. are somewhat smaller (with a low polyp body wall in fixed specimens, Fig. 8 D–F), than those of other representatives of the genus. A scant set of the sclerite types (spindles, clubs, 8-radiate capstans and ovals) clearly differentiate this species ( Table 1). Tentacles of С. lukini sp. nov. contain neither the warty clubs nor the flattened bodies that occur in other representatives of the genus ( Table 1).

Calcigorgia lukini sp. nov. coincides with C. herba sp. nov. in the presence of poorly developed leafy clubs ( Figs 2D, 3B, 5F, 6D, 9B, 11B) and spindles with tall and asymmetrically developed processes in polyp tentacles ( Figs 2E, 5C, 9A, 11A). However, С. lukini sp. nov. differs from C. herba sp. nov. in the absence of warty rods, scales and warty clubs in tentacles and, also, in the absence of clubs in the polyp body wall ( Table 1). Finally, С. lukini sp. nov. is the only species in the genus containing only capstans and ovals in the polyp body wall and a single sclerite type in the coenenchyme – 8-radiate capstans ( Table 1). C. gigantea Matsumoto, Ofwegen & Bayer, 2019 also contains a single sclerite type in the coenenchyme, but these are spindles ( Matsumoto et al. 2019).

Distribution

This species is known only from the Kurile Islands and Shelikhov Bay, Sea of Okhotsk, Northwestern Pacific, between 50 and 100 m depth.