Psammogorgia arbuscula var. dowii Verrill, 1868

Breedy, Odalisca & Guzman, Hector M., 2020, A revision of the genus Psammogorgia Verrill, 1868 (Cnidaria, Anthozoa, Octocorallia) in the tropical eastern Pacific Ocean, ZooKeys 961, pp. 1-30 : 1

Psammogorgia arbuscula var. dowii Verrill, 1868 Figures 5 , 6

Psammogorgia arbuscula var. dowii Verrill, 1868b: 415; Kükenthal 1919: 237; Harden 1979: 117.

Psammogorgia arbuscula dowii Kükenthal, 1924: 107.

Type material.

Syntypes: YPM 1787, dry, Pearl Islands, Panamá, F.H. Bradley, 1866-1867, no additional data. YPM 8684 (fragments, mixture of species), not P. arbuscula var. dowii , dry, Pearl Islands, Panamá, F.H. Bradley, 1866-1867, no additional data.

Description.

The syntype YPM 1787 is a small, 5.8 cm long dark red colony of two dichotomous branches. A 1.1 cm long stem arises from an oval holdfast ~ 1 cm in diameter (Fig. 5A ). The holdfast is covered by a thin layer of coenenchyme without polyps. The stem is 2.0 mm in diameter and bifurcates, subdividing in two branchlets up to 3.5 cm long. The branchlets are of the same diameter as the stem, with rounded tips. The branchlets bifurcate at angles of 45°, ascending parallel and are slightly curved. Terminal branchlets are 6-35 mm long (Fig. 5A ). The coenenchyme is granulose and brittle. Coenenchymal sclerites are of different forms: irregular spindles with acute or bifurcated ends, some are slightly curved (Fig. 6A ), 0.14-0.21 mm long and 0.05-0.09 mm wide. Warty radiates and crosses are 0.13-0.15 mm long and 0.10-0.11 mm wide (Fig. 6B ). Wart-clubs are 0.11-0.18 mm long and 0.05-0.085 mm wide at the expanded head being variable in form with a larger end expanded and covered with thorny warts and leaf-like projections (Fig. 6C ). Coenenchymal sclerites are of various colours: orange, red, and darker (Fig. 5C ).

The calyces are arranged all around the branches, not very close, slightly raised up to 0.5 mm tall as small mounds composed of eight marginal lobes with small polyp apertures at the summits (Fig. 5B ). Thorny, irregular spindles and some wart-clubs appear often, around the calyx aperture. The anthocodial armature is well developed and composed of spiny spindles arranged in a collaret and points, 0.12-0.20 mm long and 0.032-0.056 mm wide (Fig. 6D ); its flat rods are with small tubercles and scattered warts. Anthocodial sclerites are red and orange (Fig. 5C ).

Remarks and comparison.

The calyces in this specimen are more separated and do not have swollen polyp apertures as in P. arbuscula typica . Verrill (1868b) mentioned a more flabellate colony but YPM 1787 is not flabellate having only a few branches. Verrill (1868b) did not provide data approximately the size of sclerites of this variety, uniquely pointing out that the sclerites resemble the ones of P. arbuscula typica . We found that the sclerites of the only specimen of this variety are smaller and similar to, the ones of P. arbuscula typica . Specimen YPM 8684 corresponds to several colony fragments belonging to P. teres , P. arbuscula and an undetermined species.

Distribution.

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

Figures

Figure 5. Psammogorgia arbuscula var. dowii Verrill, 1868. YPM 1787 A colony B detail of branches C coenenchymal and anthocodial sclerites.

Figure 6. Psammogorgia arbuscula var. dowii Verrill, 1868. YPM 1787 A spindles B radiate and cross C wart clubs D anthocodial spindles.