Review Article |
Corresponding author: Odalisca Breedy ( odaliscab@gmail.com ) Academic editor: Bert W. Hoeksema
© 2020 Odalisca Breedy, Hector M. Guzman.
This is an open access article distributed under the terms of the CC0 Public Domain Dedication.
Citation:
Breedy O, Guzman HM (2020) A revision of the genus Psammogorgia Verrill, 1868 (Cnidaria, Anthozoa, Octocorallia) in the tropical eastern Pacific Ocean. ZooKeys 961: 1-30. https://doi.org/10.3897/zookeys.961.54846
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The species of the genus Psammogorgia Verrill, 1868 from the shallow waters of the tropical eastern Pacific were mainly described from 1846 to 1870. Very few contributions were published subsequently. Recently, the genus was revisited with the addition of two new species. However, a comprehensive generic study is still missing for the eastern Pacific. Psammogorgia is characterised by having axes cores without mineralisation, mainly coarse irregular spindles and thorny, leafy or tuberculate clubs coenenchymal sclerites and the anthocodial armature with distinct collaret and points arrangements. Herein a taxonomic revision of the genus is presented based on type material which was morphologically analysed and illustrated using optical and scanning electron microscopy. Comparative character tables are provided for comparison among species in the genus, along with a taxonomic key. Moreover, the taxonomic status of each species was analysed. The genus Psammogorgia comprises six valid species and two varieties, and three lectotypes and a new combination are proposed to establish the taxonomic status of these species.
Biodiversity, gorgonians, key to plexaurid genera, octocoral, Plexauridae, taxonomic review, taxonomy
Seven genera in the family Plexauridae have been reported for the tropical eastern Pacific: Muricea, Lamouroux, 1821; Thesea Duchassaing & Michelotti, 1860; Swiftia Duchassaing & Michelotti, 1864; Heterogorgia Verrill, 1868a; Psammogorgia Verrill, 1868a; Adelogorgia Bayer, 1958 and Chromoplexaura Williams, 2013. Previous taxonomic reviews of Plexauridae for the region dealt with Heterogorgia Verrill, 1868a and Muricea Lamouroux, 1821 (
The genus Psammogorgia Verrill, 1868a was established by Verrill to place a species previously assigned to the genus Echinogorgia Kölliker, 1865 (E. arbuscula Verrill, 1866), which was subsequently named Psammogorgia arbuscula (Verrill, 1868a). Later,
From 1868 to 1951 more species were described within the genus Psammogorgia from different regions and bathymetric ranges (
The status of most species of the genus Psammogorgia is uncertain because the previous authors did not designate holotypes and the illustrations of specimens and sclerites in old publications are mostly insufficient for proper species identification. Additionally, some species have been described from one to few specimens or fragments, while their type material is lost to science or their location unknown. According to
Acronyms
MCZMuseum of Comparative Zoology, Harvard University, Boston, USA.
MNHN Muséum national d’Histoire naturelle, Paris, France.
NMNM /
YPM Yale Peabody Museum of Natural History, New Haven, USA.
The type specimens used in this study were analysed during visits to museums or acquired on loan from the MCZ, MNHN, NMNM, and YPM. For the species Psammogorgia fucosa (Valenciennes, 1846), the only type material available is a sclerite slide found in the MCZ. Depth of collection of the type specimens was not recorded; however, most of the types collected by F.M. Bradley were obtained by pearl divers between 8 and 12 m in depth (
The taxonomic identification and description of the octocorals was based on external morphology: shape, size and colour of the colonies, and calyx structures, as well as on internal morphology: sclerites content, dominance, shape, size and arrangement. Terminology used in this study mostly follows
In order to prepare the sclerome for imaging and measurements, different microscope preparations were made. For optic microscopy, sclerites were mounted in water or glycerine and photographed with an Olympus LX 51 inverted microscope. For SEM, sclerites were mounted on SEM stubs by double stick carbon tape and silver paint bridges between the tape and the stubs were made to increase the electronic conduction. The samples were then sputter-coated with gold, 30–60 nm layer, in an Eiko IB-5 Ion Coater and the pictures were obtained using a Hitachi SEM S-3700N. Unsorted optic microscope micrographs reveal colour details and sclerites composition while the SEM illustrations show details and sculpture of the sclerites. Not all sclerite types of a species are presented in the SEM figures. Measurements of the sclerites were obtained from the SEM images, and for P. fucosa from the optical micrographs the length of the sclerites was measured from one tip to the other and the width was taken from the most distant points across the sclerites, reporting the largest sizes found in the samples. Because type material was generally in bad condition, the anthocodial sclerite arrangement at the base of the polyps was not described in some cases. The diameter of the branches, branchlets, and stems was noted, taking the length of the calyces into account.
Designation of lectotypes was done for three species with unclear identity described by either Verrill or Valenciennes without type designation. Lastly, data on geographical distributions are based on our personal collections (Museo de Zoología, Universidad de Costa Rica, Naos Laboratory, Smithsonian Tropical Research Institut, Panamá,
1 | Coenenchyme contains massive unilateral spinous sclerites. Polyps retract into shelf-like or tubular calyces | Muricea |
– | Coenenchyme does not contain unilateral spinous sclerites. Polyps do not retract into shelf-like or tubular calyces | 2 |
2 | Calyces with lobed rims armed with strongly projecting thorns forming a bristling barricade around calycular apertures. Axis’s cores with organic fibres mineralised with carbonate hydroxylapatite | Heterogorgia |
– | Calyces without lobed rims armed with strongly projecting thorns forming a bristling barricade around calycular apertures. Axis’s cores with organic fibres non-mineralised with carbonate hydroxylapatite | 3 |
3 | External coenenchyme with characteristic large rugose plates having the inner side with low composite warts, and the outer side with wide lobes | Thesea |
– | External coenenchyme without characteristic large rugose plates having the inner side with low composite warts, and the outer side with wide lobes | 4 |
4 | External coenenchyme with conspicuous double disk sclerites with one side expanded in longitudinal crests with various degrees of ornamentation | Adelogorgia |
– | External coenenchyme without conspicuous double disk sclerites, with one side expanded in longitudinal crests with various degrees of ornamentation | 5 |
5 | Coenenchymal sclerites mainly thin, sharp spindles with or without fused tubercles in incomplete disks. Anthocodial armature with a few bar-like rods transversely arranged not forming distinct collaret and points | Swiftia |
– | Coenenchymal sclerites without thin, sharp spindles fused in incomplete disks. Anthocodial armature forming distinct collaret and points | 6 |
6 | Coenenchymal sclerites mainly coarse, irregular spindles and thorny, foliate or tuberculate clubs | Psammogorgia |
– | Coenenchymal sclerites mainly radiates and spindles, without foliate or tuberculate clubs | Chromoplexaura |
Subclass Octocorallia Haeckel, 1866
Order Alcyonacea Lamouroux, 1816
Family Plexauridae Gray, 1859
Psammogorgia
Verrill, 1868a: 414;
Echinogorgia arbuscula Verrill, 1866 by subsequent designation (
Colonies bushy to flabellate. Branching lateral, dichotomous, irregularly dichotomous, or subpinnate. Branches round or slightly flattened. Axis horny, chambered central core filled with organic non-mineralised fibres. Calyces on all sides of branches, flat, slightly raised or prominent. Polyp apertures slit-like or swollen. Anthocodial sclerites mostly large, elongated, warty, spinose or slender spindles, with or without median waist, in collaret and points arrangements at base of tentacles. Sclerites of coenenchyme thick, warty spindles; radiates, and crosses. Clubs warty or foliate-like with variation of those types mostly present at calyx rims and external coenenchyme. Colony colours dark red, red, orange, pink and white. Sclerites colours red, pink, orange, yellow, various hues of these, and/or colourless.
The genus has been reported from the eastern Pacific, Californian province, the Indian Ocean and the north Atlantic.
Axes analysis of the species of Psammogorgia show chambered central cores filled with organic non-mineralised fibres (e.g., Fig.
Echinogorgia arbuscula Verrill, 1866: 329.
Psammogorgia arbuscula
Verrill, 1868a: 414; 1868b: 414–415; not
Psammogorgia arbuscula typica Kükenthal, 1924: 107.
Lectotype (designated herein). YPM 573, dry, Pearl Islands, Gulf of Panamá, Panamá, F.H. Bradley, 1866–1867, no additional data.
Paralectotypes. YPM 573 a-h; MCZ 425B, MCZ 573 (part of YPM 573), MCZ 727, 728A-B (4916=YPM 1577), MCZ 4017–4019, MCZ 4021–4022, MCZ 4024, MCZ 4998 (=MCZ 728) same data as the lectotype. MCZ 7009, dry, Nicoya Gulf, Costa Rica, collected by pearl divers, J.A. Mc. Neil, 1866–1867, no additional data.
Pearl Islands, Panamá.
Colonies bushy, irregularly dichotomous. Stems short, slightly flattened, one to several stems emerging from a common holdfast. Branches and branchlets thin, rounded with long free ends in large colonies. Holdfasts encrusting with a thin layer of coenenchyme often with polyps. Coenenchyme of branches moderately thick and granulose. Coenenchymal sclerites: irregular spindles with acute or bifurcated ends, up to 0.30 mm long; warty and irregular radiates up to 0.13 mm long and some crosses. Calyces prominent and swollen, all around the branches, mostly closely placed in two or three longitudinal rows on each side of the branches. Calyces with thorny and irregular spindles and wart-clubs, up to 0.19 mm long, around the calyx rim. Anthocodial spindles up to 0.26 mm long, in collaret and points arrangements. Sclerites red and orange. Dry colonies red to red-orange, dark red when alive. Polyps bright yellow when alive.
(see also
Most of the type material of the form typica of P. arbuscula is constituted of small colonies 5–15 cm long and 3–7 cm wide or fragments of colonies, the largest specimen being MCZ 7009 (28 cm long and 20 cm wide), with unbranched ends up to 15 cm long. Stems can reach up to 4 mm diameter, branches up to 3.5–3.8 mm in diameter and branchlets up to 2.0–2.6 mm in diameter. The sclerites content is consistent among the types. When alive, the colonies are dark red and the polyps are bright yellow (
Tropical eastern Pacific: Panamá, Costa Rica, Ecuador, México and El Salvador.
The Psammogorgia arbuscula typica is different in calyx structure, size of sclerites and colour from the varieties P. arbuscula var. dowii and P. arbuscula var. pallida (see Tables
Comparative features of Psammogorgia colonies from the tropical eastern Pacific, according to analyses of type material from museums (YPM, MCZ, MNHN), and taxonomic descriptions by
Species | Colony colour | Colony shape and branching pattern | Maximum # branching | Length of terminal branchlets | Diameter of branchlets | Branch anastomosis | Calyx of branchlets | Presence of swollen calyx rims | Calyx arrangement at branchlets |
---|---|---|---|---|---|---|---|---|---|
P. arbuscula (Verrill, 1866) | dark red | bushy, irregularly dichotomous | 8 | 2.5–15 | 2–4 | absent | prominent | yes | close |
P. arbuscula var. dowii Verrill, 1868b | dark red | *flabellate, dichotomous | 2 | 6–35 | 2 | absent | slightly raised | no | sparse |
P. arbuscula var. pallida Verrill, 1868b | yellowish | flabellate, irregularly dichotomous | 15 | 40 | 2–3 | absent | flat/ slightly raised | no | sparse |
P. fucosa Valenciennes, 1846 | reddish | bushy, irregularly dichotomous | 12 | 12.7–25.4 | 3–4.5 | absent | flat | no | sparse |
P. gracilis Verrill, 1868 | red | *flabellate, irregular dichotomous | 9 | 60 | 1.5–1.6 | absent | prominent | yes | close |
P. hookeri Breedy & Guzman, 2014 | coral red | bushy, irregularly dichotomous | 8 | 10–15 | 2–2.5 | absent | prominent | yes | close |
P. pax |
white | flabellate, irregularly dichotomous | 20 | 10–125 | 3–4 | present | slightly raised | no | sparse |
P. teres Verrill, 1868 | red orange | bushy, irregularly dichotomous | 12 | 5–60 | 3–5 | absent | flat | no | sparse |
Comparative features of sclerites of Psammogorgia species in the tropical eastern Pacific Ocean according to an analysis of type material from museums (YPM, MCZ, MNHN) and taxonomic descriptions by
Species | Spindle length (mm) | Wart club length (mm) | Radiates length (mm) | Anthocodials length (mm) | Colour of coenenchymal sclerites | Colour of anthocodial sclerites |
---|---|---|---|---|---|---|
P. arbuscula (Verrill, 1866) | 0.14–0.30 | 0.09–0.18 | 0.07–0.13 | 0.12–0.26 | dark red, red, orange | red, orange |
P. arbuscula var. dowii Verrill, 1868 | 0.14–0.21 | 0.11–0.18 | 0.13–0.15 | 0.12–0.20 | dark red, red, orange | red, orange |
P. arbuscula var. pallida Verrill, 1868 | 0.15–0.23 | 0.11–0.16 | 0.08–0.16 | 0.11–0.23 | pale pink, colourless | orange red |
P. fucosa Valenciennes, 1846 | 0.10–0.22 | 0.10–0.18 | 0.09–0.11 | 0.10–0.21 | red, pink, colourless | red |
P. gracilis Verrill, 1868 | 0.12–0.24 | 0.11–0.25 | 0.08–0.10 | 0.11–0.20 | red, orange, yellow | orange, pale yellow |
P. hookeri Breedy & Guzman, 2014 | 0.12–0.19 | 0.11–0.16 | 0.09–0.11 | 0.10–0.18 | coral red, reddish | yellowish, pale pink |
P. pax |
0.21–0.24 | 0.13–0.33 | not found | 0.21–0.26 | colourless | orange |
P. teres Verrill, 1868 | 0.11–0.20 | 0.07–0.16 | 0.07–0.14 | 0.13–0.26 | red, orange, colourless | pale yellow, colourless |
Psammogorgia arbuscula var. dowii
Verrill, 1868b: 415;
Psammogorgia arbuscula dowii Kükenthal, 1924: 107.
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.
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.
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.
The calyces in this specimen are more separated and do not have swollen polyp apertures as in P. arbuscula typica.
Tropical eastern Pacific: only reported from the type locality, Pearl Islands, Panamá.
Psammogorgia arbuscula var. pallida
Verrill, 1868b: 415–416;
Psammogorgia arbuscula pallida Kükenthal, 1924: 107.
Syntypes : MCZ 729 (4916), YPM 1785a-b, dry, Pearl Islands, Panamá, F.H. Bradley, 1866–1867, no additional data.
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.
The syntypes
YPM 1785a, b are two fragments of a lighter colour than MCZ 729 (Fig.
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 (
Tropical eastern Pacific: only reported from the type locality at Pearl Islands, Panamá.
Gorgonia fucosa Valenciennes, 1846: pl. 15
Plexaura fucosa
Milne-Edwards & Haime, 1857: 154;
Psammogorgia fucosa
Verrill, 1868b: 417; 1870: 556–557; 1869: 427;
Mazatlán, México, Pacific coast (
Plate 15, figured specimen (
Colony dull reddish. Colonies bushy and irregularly dichotomous. Stems short and up to 12.5 mm in diameter. Branchlets up to 4.5 mm in diameter. Calyces flat, sparsely distributed all around the branches. Coenenchymal sclerites red, pink or colourless, mostly spindles up to 0.22 mm long; wart-clubs, up to 0.18 mm long; and warty radiates. Anthocodial spindles red, up to 0.21 mm long.
Valenciennes´ figured type was originally presented in natural size (Fig.
The coenenchymal sclerites vary remarkably in diversity of colour, size and form as Verrill has pointed out. Verrill found white, yellowish, light red, deep red and amethystine intermingled sclerites while we observed transparent, red and pink sclerites in the MNHN slide. The MNHN sclerites show a diversity of sclerites that is typical of the genus: mostly irregular warty spindles with acute, blunt or bifurcated ends, and several irregular forms (Figs
Verrill´s description of sclerites was based on the MNHN sclerite slide that was sent to him at the MCZ for analysis, probably by R.A. Kölliker (
Tropical eastern Pacific: only reported from the type locality at Mazatlán, México.
Psammogorgia gracilis
Verrill, 1868b: 417–418;
Heterogorgia gracilis Harden, 1979: 112–113.
Lectotype (designated herein): YPM 813a, dry, Pearl Islands, Panamá, F.H. Bradley, 1866–1867, no additional data.
Paralectotype : YPM 813b, dry small fragment, same data as the lectotype.
Pearl Islands, Panamá.
Colonies red, tall, flabelliform, branches subparallel and elongated. Stem a few centimetres long. Calyces close together and all around the branches. Calyces slightly raised and swollen with concentration of wart-clubs up to 0.25 mm long, and acute spindles around the calyx rim. Coenenchymal sclerites: irregular spindles with acute or bifurcated ends up to 0.20 mm long; warty and irregular radiates and some crosses. Anthocodial spindles up to 0.24 mm long in collaret and points arrangements. Sclerites red and orange or of lighter hues.
The lectotype colony is red and 10 cm long and ~ 6 cm wide. Branching is irregularly dichotomous. The holdfast is absent. The branches emerge at angles of 45–90°, ascend parallel and slightly curve. The main branch of the colony is 2.5 mm in diameter subdividing into long, slender, ascending branchlets, 1.5–1.6 mm in diameter. Branches are round, slender, some extending up to 6.3 cm, undivided or bifurcating at the ends. Branches subdivide up to nine times while terminal branchlets are up to 60 mm long with rounded slightly tapered tips. (Fig.
This species differs from the others by having long, slender and ascending branchlets, which are thinner than in the other species of the genus (Table
Tropical eastern Pacific: only recorded at the type locality Pearl Islands, Panamá.
Psammogorgia hookeri Breedy & Guzman, 2014: 2–5.
Isla Gallán, Paracas National Reserve, Perú.
Colonies coral red, small, bushy, multiplanar and irregularly dichotomous. Coenenchyme granular. Coenenchymal sclerites: wide, irregular spindles with acute or bifurcated ends, and combinations of both; warty and irregular radiates, crosses and conspicuous star-like radiates. Colours of coenenchymal sclerites reddish, coral red, and lighter. Calyces prominent, swollen and closely placed. Thorny, irregular spindles, and wart-clubs around the calyx rim up to 0.16 mm long. Anthocodial spindles, thin and spiny, in collaret and points arrangements, yellowish, and pale pink in colour. We refer to
This species has only been reported for Perú, Isla Gallán, Paracas National Reserve at 25 m depth, and from Bahía Independencia at unknown depth (Fig.
Psammogorgia pax
Hannibal Bank, Gulf of Chiriquí, Pacific Panamá.
Colonies white, flabellate and branching in one plane, profuse irregularly dichotomous with occasional anastomosis. Calyces slightly raised, not close together with spiny lobes around polyp apertures. Thorny, irregularly-shaped spindles, and wart clubs around the calyx rims; wart clubs up to 0.26 mm long. Coenenchyme granular. Coenenchymal sclerites white, irregular spindles with acute or bifurcated ends or combinations of both as well as warty and irregular radiates. Anthocodial spindles orange, thin and spiny, in collaret and points arrangements. We refer to
This species has only been reported from its type locality in the upper mesophotic habitats of the Hannibal Bank at 63 m depth.
Psammogorgia teres
Verrill, 1868b: 416–417;
Lectotype (designated herein). YPM 1556b, dry, Pearl Islands, Gulf of Panamá, Panamá, F.H. Bradley, 1866–1867, no additional data.
Paralectotype. YPM 1556a, c, same data as the lectotype.
Pearl Islands, Panamá.
Colonies red or orange when preserved but brighter when alive. Colonies bushy and branch laterally and irregularly dichotomous. Stems vary from few millimetres up to 5 cm long, and 6 mm in diameter. Holdfasts encrusting with thin coenenchyme, often with polyps. Calyces flat, sparsely distributed all around the branches. Calyces with thorny, irregular spindles and wart-clubs around the calyx rim. Coenenchyme compact. Coenenchymal sclerites red, orange or colourless, mostly irregular warty spindles with acute or bifurcated ends and asymmetrical forms with prominent warty tubercles up to 0.20 mm long; wart-clubs with wide heads, up to 0.16 mm long; warty radiates and crosses. Anthocodial spindles pale yellow or colourless, flat or spiny, up to 0.26 mm long and in collaret and points arrangements. Coenenchymal sclerites red, orange and colourless, anthocodial rods pale yellow and colourless.
The lectotype is a red orange dry colony, which was brighter when alive (
While the largest anthocodial sclerite measured in the lectotype was 0.24 mm long, Verrill (1886b) mentioned a slightly larger length of 0.26 mm. This is in accordance to the anthocodials of other specimens revised in this study. The syntype YPM1556b closely fits
Psammogorgia teres has a colony morphology similar to that of P. fucosa (Table
In comparison with P. arbuscula and P. gracilis, P. teres differs in the external morphology represented by colonies with thicker branches and flat calyces; and relative abundance and sizes of sclerites (Tables
The species occurs in Pearl Islands, Panamá (type locality) and also in in the Chiriquí Gulf, Panamá. However, the species presents a wider regional distribution in the tropical eastern Pacific. It was sampled by us, along the Pacific coast of Costa Rica, El Salvador, Nicaragua, and Ecuador, and encountered in collections from the Pacific coasts of México and Colombia.
The genus Psammogorgia comprises six species and two varieties belonging to two morphological species-groups: Psammogorgia arbuscula group consisting of P. arbuscula, P. gracilis, P. hookeri and P. pax. and the Psammogorgia teres group consisting of P. teres and P. fucosa. We have explored and collected Psammogorgia species in Costa Rica, El Salvador, Nicaragua and Panamá, and have revised collections from Colombia, Ecuador, México and Perú. We found P. arbuscula and P. teres from these localities; nonetheless, P. gracilis and the two varieties of P. arbuscula were not found as additional records. Regarding P. digueti, after our analysis of a specimen in the MNHN we conclude that it belongs to a different genus and its status has to be revised. Lastly, P. hookeri and P. pax seem to be endemic to their regions, the first one from Perú and the other from mesophotic habitats off the Pacific coast of Panamá. However, without more explorations and further records, the geographic distribution and species richness of Psammogorgia is incomplete.
1 | Colony white. Calyces slightly raised. Deep water species (> 60 m) | P. pax |
– | Colony red or of different hues of red. Calyces prominent to flat. Shallow water species (< 40 m) | 2 |
2 | Calyces prominent with swollen polyp apertures | 3 |
– | Calyces flat without swollen polyp apertures | 5 |
3 | Colony coral red. Wart clubs < 0.16 mm in length. Star-like radiates present in coenenchyme | P. hookeri |
– | Colony red or dark red. Wart clubs > 0.16 mm in length. Star-like radiates absent from coenenchyme | 4 |
4 | Branch diameter > 2 mm. Anthocodial spindles > 0.20 mm in length | P. arbuscula |
– | Branch diameter < 2 mm. Anthocodial spindles < 0.20 mm in length | P. gracilis |
5 | Terminal branchlets long (> 25 mm). Anthocodial spindles pale yellow to colourless and >0.20 mm in length | P. teres |
– | Terminal branchlets long (< 25 mm). Anthocodial spindles red and < 0.20 mm in length | P. fucosa |
Our appreciation to Bert W. Hoeksema (Naturalis Biodiversity Center, Leiden, the Netherlands) for the taxonomic discussion and critical review of the manuscript. We thank Gary Williams (California Academy of Science, Invertebrate Zoology, San Francisco, USA) and Íris Sampaio (Marine and Environmental Sciences Centre of the Institute of Marine Research, Portugal) for their time and suggestions to improve this publication. We thank Leen van Ofwegen (Naturalis Biodiversity Center, Leiden, the Netherlands) and Stephen Cairns (NMNM, Washington, DC, USA) for revising a preliminary version of the manuscript.
Eighteen years after of the publication of our first taxonomic revision and our proposal to revise the seven gorgonian genera historically reported for the shallow waters of the eastern Pacific, we have to express our immense gratitude to all colleagues, collection managers, revisers, collectors and friends who made this project possible. Our appreciation goes to the experts in taxonomy of octocorals: Stephen Cairns; Leen van Ofwegen; Gary Williams; Phil Alderslade, CSIRO Marine and Atmospheric Research Oceans & Atmosphere, Tasmania, Australia; Manfred Grasshoff, former octocoral curator at Forschungsinstitut und Naturmuseum Senckenberganlage, Frankfurt, Germany and Juan Armando Sánchez, Laboratorio de Biología Molecular Marina (BIOMMAR) Universidad de Los Andes, Bogotá, Colombia. We acknowledge the following people and institutions for their generosity in making available specimens and information used though this project: Eric Lazo-Wasem and Lourdes Rojas, YPM; Ardis Johnston (former collection manager and curator) and Adam Baldinger, MCZ; Marie J. d´Hondt (former collection manager and curator), Aude Andouche, MNHN; Sheila Halsey (former collection manager and curator), Andrew Cabrinovic and Tracy Heath, Museum of Natural History, London, UK; Stephen Cairns, Tim Coffer, Chad Walter, Geoff Keel, NMNH; Leen van Ofwegen, Naturalis Biodiversity Center, Leiden; Karin Sindemark Kronestedt and Elin Sigvaldadottir, Swedish Museum of Natural History, Stockholm, Sweden; Ole Tendal; Bernhard Ruthensteiner and Eva Lodde, Zoologische Staatssammlung München, Germany; Peter Stiewe and Helma Roggenbuck, Zoologisches Institut und Zoologisches Museum der Universität Hamburg, Germany; Lisa Levi, Museo Zoologico dell’Università di Firenze, Firenze, Italy; Cecilia Volpi, Museo Regionale di Scienze Naturali, Torino, Italy; Gary Williams and Bob Vansyoc, California Academy of Science, Invertebrate Zoology, San Francisco, USA; José Luis Carballo, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México; Yuri Hooker, Colecciones Biológicas, Universidad Peruana Cayetano Heredia, Lima, Perú ; Fernando Rivera and Priscilla Martínez, NAZCA Instituto de Investigaciones Marinas, Salinas, Ecuador; Miguel Romero Instituto del Mar de Perú, Lima, Perú and Juan Armando Sánchez, BIOMMAR.
We are grateful to Alexander Rodríguez, Centro de Investigación en Estructuras Microscópicas, Universidad de Costa Rica for composition of plates; Cristian Mora and Wendolyn Matamoros (Universidad de Costa Rica) for laboratory assistance and microscopic preparations. We thank Yuri Hooker (UPCH) and Manu San Felix, National Geographic, Pristine Seas for the Psammogorgia underwater pictures presented here.
This project was partially sponsored by the Smithsonian Tropical Research Institute, the Smithsonian Institution, and the Vicerrectoría de Investigación, Universidad de Costa Rica, projects 808-A9072, 808-B2142 and 810-B5159, and the Secretaría Nacional de Ciencia, Tecnología e Innovación de Panamá (SENACYT).