Psammogorgia arbuscula var. pallida Verrill, 1868 Figures 7, 8, 9

Psammogorgia arbuscula var. pallida Verrill, 1868b: 415-416; Kükenthal 1919: 237; Harden 1979: 119.

Psammogorgia arbuscula pallida Kükenthal, 1924: 107.

Type material.

Syntypes: MCZ 729 (4916), YPM 1785a-b, dry, Pearl Islands, Panamá, F.H. Bradley, 1866-1867, no additional data.

Description.

The syntype MCZ 729 is a yellowish flabellate, 10.5 cm long and ~ 9 cm wide colony. Two main stems arise from a holdfast that is 1.6 cm in diameter nd devoid of polyps (Fig. 7A). The stems are less than 1 cm tall and 2.5 mm in diameter, subdividing irregularly in secondary branchlets of 2-3 mm diameter with rounded tips (Fig. 7A). The branchlets emerge at angles of 45-180° and spread irregularly in one plane. The colony branches up to 15 times. Terminal branchlets are up to 40 mm long (Fig. 7A). The polyps occur all around the branches, 1-1.5 mm apart on branchlets and 1.5-2.5 mm apart on the branches. The calyces are almost flat with a few being ~ 0.02 mm tall with oval or round polyp-apertures. Thorny, irregular spindles and wart-clubs occur around the calyx rim (Fig. 7B). The coenenchymal sclerites are mostly irregular tuberculate spindles (Figs 7B, 8A) with acute or bifurcated ends or combinations of both (Fig. 8A) with colours varying from pale pink to mostly colourless (Fig. 7B). These sclerites are 0.15-0.23 mm long and 0.04-0.09 mm wide. Wart clubs are 0.11-0.14 mm long and 0.05-0.06 mm wide with warts or with wide tubercles (Fig. 8B). Crosses various intermediate forms and radiates are 0.08-0.16 mm long and 0.07-0.12 mm wide with tubercles (Fig. 8C). The anthocodial armature is composed of slightly bent spiny orange-red sclerites arranged in a collaret and points, 0.11-0.23 mm long and 0.02-0.045 mm wide (Figs 7B, 8D).

The syntypes YPM 1785a, b are two fragments of a lighter colour than MCZ 729 (Fig. 9B). The largest fragment is 5.6 cm long and composed of four branchlets with 2-3 mm in diameter; flat calyces all around the branches (Fig. 9A). All sclerites, including the anthocodials, are pale yellow to colourless. Sclerites from the syntypes are more ornamented than in specimen MCZ 729 but mostly colourless (Fig. 9B). The coenenchymal sclerites are mostly irregular, tuberculate warty spindles with acute or bifurcated ends or combinations of both; being 0.13-0.18 mm long and 0.035-0.08 mm wide. Clubs have a few warts or with wide tubercles being 0.11-0.16 mm long and 0.05-0.60 mm wide. Radiates have tubercles appearing in various intermediate forms, being 0.07-0.10 mm long and 0.05-0.08 mm wide. The anthocodial armature is composed of slightly bent spiny spindles arranged in collaret and points, 0.12-0.22 mm long and 0.025-0.043 mm wide.

Remarks and comparison.

Verrill´s material at MCZ includes two specimens, MCZ 729 (4916) and YPM 1785, both with similar sclerites but different in external morphology. One is a small colony and the other is a small fragment in bad condition. According to Verrill´s description (Verrill 1868b) the type material has a "corallum more or less flabelliform, branching dichotomously, branchlets round, sometimes as large as the main stem, usually smaller. Cells a little raised forming low verrucae". However, Verrill did not measure the specimens. YPM 1785 is different from Verrill’s description while MCZ 729 (4916) matches some details of his description. Orange-red anthocodial sclerites are present in MCZ 729, as well as at the P. arbuscula var. pallida description by Verrill (1868b), in contrast with the colourless rods in specimen YPM 1785. Also, pale pink, colourless, and transparent coenenchymal sclerites match his description (Fig. 7B). In terms of sclerite sizes, Verrill’s description better matches MCZ 729 with larger sclerite sizes than the smaller YPM 1785 ones. As Verrill suggested, with this and dowii variety, we opt to keep P. arbuscula var. pallida as a variety.

Distribution.

Tropical eastern Pacific: only reported from the type locality at Pearl Islands, Panamá .