Heterogorgia papillosa Verrill, 1870

(Figs. 4, 5)

Heterogorgia papillosa Verrill, 1870: 557; Kükenthal 1924: 232; Harden 1979: 113.

Material examined. Holotype: YPM 8609, dry, La Paz, Baja California Sur, Mexico, 11–15 m, J. Pedersen, date unknown.

Description of the holotype. The colony is 10.5 cm tall and 8 cm wide (Fig. 4 A), consists of two main branches that arise from a naked, 1 cm long stem without holdfast. The branching is sparse and irregular; the branches subdivide up to four times, and are 3–4 mm in diameter. The calyces are prominent, about 0.5–1 mm tall and up to 0.5 mm diameter (Fig. 4 A–B); they are distributed all around the branches, not very close together (20– 25 calyces/cm); some are separated by up to 4 mm, and are even more distant at the base of branches. The anthocodial armature consists of collaret and points arrangements. The collaret is composed of one row of long, curved, acute spindles, 0.26–0.43 mm long and 0.03–0.05 mm wide (Fig. 5 A); the points have two pair of spiny spindles arranged en chevron, 0.2–0.35 mm long and 0.02–0.04 mm wide (Fig. 5 B). The calicular rim has two whorls of thorns, 0.24–0.25 mm long and 0.04–0.06 mm wide, some of which are poorly developed and look like spindles (Fig. 5 C). Tentacles have small, irregular rods 0.10–0.16 mm long and 0.015–0.02 mm wide (Fig. 4 C). Coenenchymal sclerites include: small, tuberculate radiates, 0.07–0.09 mm long and 0.05–0.055 mm wide (Fig. 5 E); spindles 0.15–0.4 mm long and 0.04–0.1 mm wide, including many different spindle-derived and branched forms with very irregular tuberculation (Fig. 5 D); and crosses 0.08–0.14 mm diameter with tuberculate arms or tuberculate all over (Fig. 5 F).

Colour of the colony is pale yellowish to white.

Remarks. The only known specimen of this species is the holotype. There is other material in the YPM from Mexico that includes specimens labelled as H. papillosa, but our examination has shown the species is not actually present. This species differs from the other three eastern Pacific species in its long, thinner branches and weaker collaret and points, and although it has similar colony form and collaret and points arrangement to H. uatumani, it differs in sclerite form and size (Table 2, Fig. 9).

This species is only known from the type locality.