Calyptrophora agassizii Studer, 1894

Cairns, Stephen D., 2018, Deep-Water Octocorals (Cnidaria, Anthozoa) from the Galapagos and Cocos Islands. Part 1: Suborder Calcaxonia, ZooKeys 729, pp. 1-46 : 8-11

Calyptrophora agassizii Studer, 1894 Figures 2c, 7

Calyptrophora agassizii Studer 1894: 63; Menneking 1905: 253-255, pl. 8, figs 5-6, pl. 9, figs 15-16; Versluys 1906: 112; Kükenthal 1919: 475; 1924: 317; Cairns 2009: 422-424 (key and phylogenetic analysis); Cairns and Bayer 2009: 31 (listed).

Material examined.

JSL-I-1922, 1 colony, USNM 1297148. JSL-I-1931, 3 branches, USNM 1161747; JSL-I-1935, 1 branch, USNM 1161749; JSL-II-3108, 1 colony, USNM 1093041; JSL-I-3907, 1 colony, USNM 1297151; syntypes.

Types.

Syntypes: several branches from which 99% of the polyps are detached, MCZ 4815, and SEM 1357-1358, NMNH. Mixed in with the type lot of C. agassizii were several branches of Narella ambigua , a species collected from the previous Albatross station (3403). These specimens were separated by me in 2008.

Type locality.

Alb-3404: 1°03'S, 89°28'W (south of San Cristóbal, Galápagos), 704 m depth.

Distribution.

Galápagos: west of Isabela, off Marchena and San Cristóbal, 509-1545 m deep.

Description.

The colony is uniplanar, equally and dichotomously branched; the largest colony (JSL-I-3108, Figure 2c) is 13 cm tall and 10 cm in width, with a basal axis diameter of 1.1 mm. The colonies are quite flexible and weak; the polyps are poorly attached and often detached after collection. Polyps are directed downward, and occur in whorls of four to six, the whorl diameter measuring 3.5-4.5 mm; the whorls are closely spaced, 4-4.5 whorls occurring per cm branch length. The horizontal length of the polyp is 1.8-2.2 mm. The pale yellow axis is slender, contributing to the flexibility of the colony.

The fused basal scale (Figures 7 d–f) stands perpendicular to the branch and is up to 2.1 mm in height, the distalmost 0.9-1.1 mm consisting of two elongate spines (Figure 7 d, f). These spines are broad basally but attenuate to projections that are circular in cross section and bear low longitudinal ridges on all their surfaces (Figure 7f). The outer surface of the basal scale is smooth (Figure 7d); the articulating ridge (Figure 7e) is well developed, about 0.7 mm in length. The fused buccal scale (Figure 7g) is up to 2.2 mm in length and is oriented parallel to the branch. The distal edge of the buccal scale consists of several broad lobes (not spines or teeth), which form a translucent cowl (Figure 7b, c) up to 0.8 mm in length, which encircles and protects most of the operculum. Like the basal scales, the outer surface of the buccal scales is smooth, the inner face covered with low granules arranged in longitudinal rows near the distal edges. The paired, strongly curved infrabasals (Figure 7i) are about 1 mm in width and only 0.3 mm in height. The opercular scales (Figure 7h) range in length from 0.45-0.90 mm, decreasing in length from ab- to adaxial polyp side, forming a relatively small operculum that is encircled by the buccal cowl; their L:W ranges from 1.9-3.3. The operculars are thin, flat, and triangular, with a blunt apex; their outer surface is smooth to slightly granular, their inner surface covered by a longitudinal keel. The coenenchymal scales (Figure 7j) are thin, flat, and elongate, with blunt ends, and up to 0.8 mm in length. Their outer surface is covered with small, low granules.

Comparisons. Only four of the 23 species of Calyptrophora have polyps oriented in the downward direction ( Cairns 2009). Calyptrophora agassizii easily differentiated from the others by having equal, dichotomous branching and keeled opercular scales.

Remarks. Several monographers have redescribed this species, but apparently based only on the type material. This is the first subsequent report of the species based on new material. The latitude reported by Studer (1894) for the type specimens is incorrect, it being 1°03'S, not north latitude.