A revision of the genus Psammogorgia Verrill, 1868 (Cnidaria, Anthozoa, Octocorallia) in the tropical eastern Pacific Ocean Author Breedy, Odalisca Centro de Investigacion en Estructuras Microscopicas, Centro de Investigacion en Ciencias del Mar y Limnologia, Escuela de Biologia, Universidad de Costa Rica. P. O. Box 11501 - 2060, Universidad de Costa Rica, San Jose, Costa Rica & Smithsonian Tropical Research Institute, P. O. Box 0843 - 03092, Panama, Republic of Panama odaliscab@gmail.com Author Guzman, Hector M. Smithsonian Tropical Research Institute, P. O. Box 0843 - 03092, Panama, Republic of Panama text ZooKeys 2020 961 1 30 http://dx.doi.org/10.3897/zookeys.961.54846 journal article http://dx.doi.org/10.3897/zookeys.961.54846 1313-2970-961-1 C5E8BED7F08549A999C60C3AA8492D09 634A9CDA65075FEE8D7C196F5E37F6FC Psammogorgia arbuscula var. dowii Verrill, 1868 Figures 5 , 6 Psammogorgia arbuscula var. dowii Verrill, 1868b: 415; Kuekenthal 1919 : 237; Harden 1979 : 117. Psammogorgia arbuscula dowii Kuekenthal , 1924: 107. Type material. Syntypes : YPM 1787, dry, Pearl Islands, Panama , F.H. Bradley, 1866-1867, no additional data. YPM 8684 (fragments, mixture of species), not P. arbuscula var. dowii , dry, Pearl Islands, Panama , 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 ). Figure 5. Psammogorgia arbuscula var. dowii Verrill, 1868. YPM 1787 A colony B detail of branches C coenenchymal and anthocodial sclerites. 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 ). Figure 6. Psammogorgia arbuscula var. dowii Verrill, 1868. YPM 1787 A spindles B radiate and cross C wart clubs D anthocodial spindles. 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, Panama .