Narella calamus,

Cairns, Stephen D., 2018, Primnoidae (Cnidaria: Octocorallia: Calcaxonia) of the Okeanos Explorer expeditions (CAPSTONE) to the central Pacific, Zootaxa 4532 (1), pp. 1-43: 29

publication ID

publication LSID

persistent identifier

treatment provided by


scientific name

Narella calamus

n. sp.

Narella calamus  , n. sp.

Figs. 1PView FIGURE 1, 14View FIGURE 14 A –H

Etymology. Named calamus  (Greek for a fishing rod), in that the unbranched colony of this species resembles a small fishing rod and is used for the purpose of catching prey.

Types and Type Locality. Holotype, and SEM stubs 2419-2422,2479-2481, USNM 1424208View Materials  . Paratypes: EX 1706-10-04, 15.04˚N, 170.87˚W ( Wetmore Seamount , off Johnston Atoll), 1994 m, one colony, USNM 1457388View Materials, 25 July 2017  ; Pisces  4-2672, 21˚30’51”N, 167˚56’22” W ( Necker Ridge ), 1793 m, 15 October 2011  , 1 colony, USNM 1170790View Materials; Pisces  4-2638, 21˚37’52”N, 167˚49’02”W ( Necker Ridge ), 1746 m, 14 October 2011  , 1 branch, USNM 1171059View Materials. Type Locality: EX 1606-6-03  : 19.4447˚N, 165.79899˚E ( Unnamed Seamount , northwest of Wake Island), 2073 m, 6 August 2016  .

Material Examined. Types.

Description. Only the distal 14.5 cm (27 whorls) of the holotype colony was collected, but in situ photographs of the type show it to be an unbranched colony approximately 77 cm in length ( Fig. 1PView FIGURE 1). The color of the colony is white. The whorls are arranged in relatively closely spaced (1.8–2.0 polyps/cm) whorls of four polyps each; the whorl diameter is about 5 mm. The horizontal length of contracted polyps is 4.4–5.0 mm. Polychaete commensalism was not noted.

The basal body wall scales are 1.8–1.9 mm in height, the distal margin serrate (but with rounded apices) and extend only slightly past the proximal portion of the medial scales ( Figs. 14A, CView FIGURE 14). The dorsolateral edge of the basal scales are rounded; none of the body wall scales are ridged, all having a smooth to slightly granular outer face. The adaxial edges of the basal scales do not meet (open position, Fig. 14BView FIGURE 14). The medial body wall scales ( Fig. 14DView FIGURE 14) are much smaller, only 1.1–1.3 mm in length. The buccal scales ( Fig. 14EView FIGURE 14) are the largest of the body wall scales, up to 2.4 mm in length and also having a slightly wavy distal edge. The ratio of major body wall scales is: 1: 0.65: 1.2, the buccal scales being larger than the basals. There is one pair of square adaxial body wall scales ( Fig. 14FView FIGURE 14), each measuring about 0.5 mm to a side, below which the polyp is naked. All body wall scales are quite thin and thus fragile and often were often broken in collection.

The abaxial opercular scales are symmetrical, up to 2.0 mm in length, with an L:W of about 1.4, often having a bifid tip. The lateral opercular scales are asymmetrical, 1.5–2.3 mm in length, having an L:W of 2.1–2.3; some of the lateral operculars also have a bifid tip. The adaxial operculars are the smallest and most slender, being symmetrical, only 1.5–1.8 mm in length, and having an L:W of 2.5–3.5. All opercular scales ( Fig. 14GView FIGURE 14) have a highly concave outer surface.

The coenenchymal scales ( Fig. 14HView FIGURE 14) are elongate (up to 1.5 mm in length, with an L:W ranging from 3.5–6.0), thin and imbricate. Most coenenchymals bear one tall longitudinal ridge on their outer surface.

Comparisons. Only two of the 27 known species of Narella  that lack a dorsolateral ridge have unbranched colonies, the other species being N. versluysi (Hickson, 1909)  (Amphi-Atlantic, 550–3100 m). Narella calamus  differs from N. versluysi  in having a serrate edge to their basal scales and much longer polyps. Narella calamus  and N. macrocalyx  have the longest polyps in the genus.

Remarks. The fragility of the corallum may be associated with the depth of capture, deep-living primnoid taxa often having thin scales and thus brittle polyps, which are prone to damage when collected.

Distribution. Off Wake Island, Johnston Atoll, and Necker Ridge, 1746-2073 m.