The Galapagos octocorals were almost unknown until recent years. Of the three orders within the subclass Octocorallia (Anthozoa, Cnidaria), the Pennatulacea (sea pens) and Alcyonacea (soft corals and gorgonians) occur in the Galapagos. Recent collections and research bring the total known octocorallian fauna to three sea pens (Virgularia galapagensis, Ptilosarcus undulatus and Cavernulina darwini) and 15 gorgonians. Of the 13 gorgonians that we have collected, several are new species. Pacifigorgia is widely distributed in the archipelago, with four named species (P. dampieri, P. symbiotica, P. rubripunctata, and P. darwinii), three of them recently described, and two others yet to be described. The genus Muricea contains three widely distributed undescribed species, one of which appears in three chromotypes, and one deepwater species that has not been collected recently. Two species of Heterogorgia occur in the central archipelago, H. verrucosa and the recently described and widely distributed H. hickmani. The remaining gorgonians are Eugorgia daniana, Leptogorgia alba and Adelogorgia telones

Breedy, Odalisca

Hickman, Cleveland P., Jr.

Williams, Gary C.

Aquatic Commons

June 2009 27Research Articles
OCTOCORALS IN THE GALAPAGOS ISLANDS
By: Odalisca Breedy1, Cleveland P. Hickman, Jr2 & Gary C. Williams3
1Centro de Investigación en Ciencias del Mar y Limnología (CIMAR), Universidad de Costa Rica 2060,
San José, Costa Rica
2Department of Biology, Washington & Lee University, Lexington, VA 24450, U.S.A.
3Department of Invertebrate Zoology and Geology, California Academy of Sciences,
Golden Gate Park, San Francisco, CA 94118, U.S.A.
SUMMARY
The Galapagos octocorals were almost unknown until recent years. Of the three orders within the subclass Octocorallia
(Anthozoa, Cnidaria), the Pennatulacea (sea pens) and Alcyonacea (soft corals and gorgonians) occur in the Galapagos.
Recent collections and research bring the total known octocorallian fauna to three sea pens (Virgularia galapagensis,
Ptilosarcus undulatus and Cavernulina darwini) and 15 gorgonians. Of the 13 gorgonians that we have collected, several
are new species. Pacifigorgia is widely distributed in the archipelago, with four named species (P. dampieri, P. symbiotica,
P. rubripunctata, and P. darwinii), three of them recently described, and two others yet to be described. The genus Muricea
contains three widely distributed undescribed species, one of which appears in three chromotypes, and one deep-
water species that has not been collected recently. Two species of Heterogorgia occur in the central archipelago, H.
verrucosa and the recently described and widely distributed H. hickmani. The remaining gorgonians are Eugorgia daniana,
Leptogorgia alba and Adelogorgia telones.
RESUMEN
Octocorales en las Islas Galápagos.  Hasta hace pocos años, los octocorales de las Islas Galápagos eran muy poco
conocidos. De los tres órdenes que comprende la subclase Octocorallia (Anthozoa, Cnidaria), los Pennatulacea
(plumas de mar) y Alcyonacea (corales suaves y gorgonias) aparecen en las Galápagos. Por medio de investigación
y recolectas recientes se ha encontrado que la fauna de octocorales está compuesta por tres plumas de mar (Virgularia
galapagensis, Ptilosarcus undulatus y Cavernulina darwini) y por 15 gorgonias. Nosotros hemos recolectado 13 gorgonias
y de ellas, algunas son especies nuevas. El género Pacifigorgia con cuatro especies descritas (P. dampieri, P. symbiotica, P.
rubripunctata y P. darwinii), tres de estas descritas recientemente, más dos probablemente nuevas, se encuentra
ampliamente distribuido en el archipiélago. El género Muricea contiene tres especies que no se han descrito y que están
ampliamente distribuidas, de las cuales una presenta tres cromotipos, más una especie de profundidad que no ha sido
recolectada recientemente. Del género Heterogorgia, dos especies aparecen en el archipiélago central, H. verrucosa y H.
hickmani. Esta última, ha sido descrita recientemente y se encuentra ampliamente distribuida. Las otras gorgonias son
Eugorgia daniana, Leptogorgia alba y Adelogorgia telones.
INTRODUCTION
The marine faunas of oceanic islands are of great bio-
geographical interest, providing insights into endemism,
dispersal patterns, and evolution through comparisons
with mainland faunas (Quammen 1996, Hickman 2009).
There are five main oceanic islands or archipelagos in the
tropical E Pacific: Cocos Island, Costa Rica; Malpelo Island,
Colombia; the Revillagigedo Islands, Mexico; Clipperton
Island, France; and the Galapagos, Ecuador. Each is
separated from the mainland by at least 435 km (Malpelo)
and up to 1300 km (Clipperton), and also by abyssal
depths (Kaiser & Bryce 2001). Numerous expeditions have
yielded a considerable literature on certain taxonomic
groups on these islands. However some groups of marine
invertebrates, including the Octocorallia, have received
little attention. Although several octocoral species have
been photographed and collected from these islands,
published records exist only from Cocos and Galapagos.
The Galapagos are the largest group of islands in the
tropical E Pacific, and the subject of considerable research,
but the marine fauna, especially the octocorals, was almost
unknown until recently. This paper summarises our
knowledge of the octocorals of Galapagos.
THE OCTOCORALS
The subclass Octocorallia (class Anthozoa) comprises
sedentary, mostly colonial marine animals, distinguished
from the true, or stony, corals by their octoradial
symmetry, pinnate tentacles, and skeletal elements of
calcium carbonate, called sclerites, in their tissue. Many
taxa also have proteinaceous and calcified axial skeletons.
The Octocorallia comprise three orders: Helioporacea
(blue corals), Pennatulacea (sea pens), and Alcyonacea
(soft corals and gorgonians). Sea pens and gorgonians
occur in the Galapagos.
28 Galapagos Research 66Research Articles
The Pennatulacea have colonies formed by a very large
primary polyp called the oozooid, on the wall of which
the coenenchyme spreads with numerous small (secon-
dary) polyps. The primary polyp may be additionally
supported by a horny axis, and part of it forms the
peduncle that anchors the colony in sand or soft sub-
strates. The other part of the oozooid forms the rachis,
which bears other kinds of polyps: autozooids and
siphonozooids. In some species the emergent part looks
like a feather (thus the name sea pens) (Williams 1990,
Fabricius & Alderslade 2000).
Alcyonacean soft corals have not been reported in the
Galapagos. Gorgonians, the most abundant octocorals in
the Galapagos, include sea rods, sea whips, sea cande-
labra, sea feather plumes and sea fans. They present very
diverse growth forms: encrusting colonies, upright fans
and bushes with slender branches, or simple whips.
Gorgonian colonies have a central axial skeleton com-
posed of a collagenous matrix called gorgonin, and
calcifications within the collagen interstitial spaces
(Jeyasuria & Lewis 1987). A layer of coenenchyme with
sclerites and polyps surrounds it.
There are an estimated 2900 species of octocorals
worldwide although new species and even genera
continue to be described at a rapid rate. In Galapagos,
nine shallow-water (< 50 m) and one deep-water octocoral
species have been reported in the literature and eight
more shallow-water species are reported here (Table 1).
The species listed in the table, except Adelgorgia telones,
which has not been collected since it was described by
Bayer (1978), are described in more detail, with photo-
graphs, in Hickman (2008).
Main identification sources are Bayer (1981) and
Williams (1995). There is also a key to octocoral families,
complete bibliography of octocoral literature and listing
of current genera by G. Williams at http://www.
calacademy.org/research/izg/isg_researchl_ink.htm.
Octocoral species are identified by colony morphology
Table 1. Distribution of shallow-water (< 50 m) octocoral species in the Galapagos Islands. * indicates records not previously
published.
Species Sites
Order Pennatulacea:
Cavernulina darwini Hickson 1921 (Veretillidae) San Cristóbal.
Virgularia galapagensis Hickson 1930 (Virgulariidae) Isabela (Tagus Cove). Santiago (James Bay).
Ptilosarcus undulatus (Verrill 1865) (Pennatulidae) Wolf, Isabela (Tagus Cove).
Order Alcyonacea: Suborder Holaxonia: Family Gorgoniidae:
Pacifigorgia dampieri Williams & Breedy 20041 Darwin, Wolf, Roca Redonda.
Pacifigorgia darwinii (Hickson 1928)1 Isabela (Cuatro Hermanos islets, Tagus Cove, Punta Moreno, Punta
Vicente Roca), Fernandina (Punta Espinosa), Floreana (La
Botella rock), San Cristóbal (and Kicker Rock), Pinzón.
Pacifigorgia symbiotica Williams & Breedy 20041 Darwin, Wolf, Isabela (Caleta Iguana, Cabo Rosa).
Pacifigorgia rubripunctata Williams & Breedy 20041 Bartolomé, Española, Rábida, Nameless, Santiago, Floreana (Gardner
islet), Isabela (Cuatro Hermanos islets), Genovesa.
*Pacifigorgia sp. 1 (P. cf. symbiotica)1 Wolf.
*Pacifigorgia sp. 2 (P. cf. rubripunctata)1 Nameless.
*Eugorgia daniana Verrill 1868 Genovesa, Nameless, Pinzón.
Leptogorgia alba (Duchassaing & Michelotti 1864) Darwin, Wolf.
Order Alcyonacea: Suborder Holaxonia: Family Plexauridae:
Adelogorgia telones Bayer 19791 San Cristóbal (Kicker Rock).
*Muricea cf. fruticosa Verrill 1868 Isabela (Cuatro Hermanos islets, Punta Vicente Roca), Nameless,
San Cristóbal (Punta Pitt, Whale Rock), Darwin.
*Muricea sp. 11 Fernandina (Cabo Douglas), Isabela (Punta Albermarle, Punta
Vicente Roca, Tagus Cove, Tortuga islet), Nameless, Pinzón,
Floreana (La Botella rock, Gardner islet), Santiago (Bainbridge
Rocks), San Cristóbal (Kicker Rock).
*Muricea sp. 2 purple variety1 Darwin, Genovesa.
*Muricea sp. 2 yellow/orange variety1 Darwin, Genovesa, Floreana (Devil’s Crown islets).
*Muricea sp. 2 white variety1 Darwin, Floreana (Devil’s Crown islets), Santa Fe (NW), San Cristóbal
(Whale Rock).
Heterogorgia hickmani Breedy & Guzman 20051 Pinzón, Floreana (La Botella rock, Devil’s Crown islets), San Cristóbal
(Kicker Rock, Five Fingers rocks), Isabela (Las Marielas islets,
Caleta Black, Tagus Cove and south of there, Punta Albemarle,
Caleta Iguana, Tortuga islet), Santa Fe (NW), Rábida, Santa Cruz
(Gordon Rocks), Española.
*Heterogorgia verrucosa Verrill 1869 Santa Cruz (Gordon Rocks).
1Known only from Galapagos.
June 2009 29Research Articles
(branching pattern, colour and shape) and sclerite
morphology (sizes, colours, forms and abundance of the
different types of sclerite). However, morphological
characteristics can be modified by the environment, and
intergrading forms may confound some identifications
(Breedy & Guzman 2003, 2007). For identification and
molecular studies, specimens ideally should be collected
complete and preserved in 70–95% ethanol (never
formalin as this dissolves the sclerites). However, most
octocorals can be identified on sclerite morphology using
a much smaller sample, as little as a few polyps. For the
study of sclerites, fragments from colonies are treated
with sodium hypochlorite to dissociate sclerites from
tissue, washed several times in distilled water, de-
hydrated with 100% ethanol, then air or oven dried and
prepared for scanning electron microscopy or light
microscopy. For further details of the methodology, see
Breedy & Guzman (2002) and http://www.calacademy.
org/research/izg/OctoResearchTech.htm.
RESULTS
The first octocoral specimen from Galapagos was a
fragment of probably Pacifigorgia darwinii collectedby
Charles Darwin in 1835 (Hickson 1921, 1928), which was
deposited in the University Museum of Zoology, Cambridge,
U.K. Unfortunately this specimen was misplaced or lost
(R. Preece pers. comm.). Two species of Pennatulacea and
three species of Pacifigorgia (under the name Gorgonia) were
reported from the C. Crossland S.Y. St George voyage
(Hickson 1928, 1930, Stiasny 1941, 1943), and one alcyona-
cean, described as Muricea galapagensis, came from the
Presidential Cruise of 1938 (Deichmann 1941). Bayer (1978)
described Adelogorgia telones from collections by W.D. Hope
in 1978. Several specimens collected during the R.V. Anton
Bruun Cruise in 1966 were deposited in the Museum of
Comparative Zoology of Harvard University and later
identified as Pacifigorgia rubripunctata (Williams & Breedy
2004). Collections made by the 1986 Harbor Branch
Oceanographic Institution expedition to the Galapagos,
Cocos, and Pearl Islands contain a number of octocorals
from deep waters that may yield new species. Collections
made by the 1994 California Academy of Science Marine
Expedition to the Galapagos, periodic marine surveys by
the Charles Darwin Research Station, Galapagos, and
numerous collections by CPH from 1996 to 2007 have
produced three new species of Pacifigorgia (Williams &
Breedy 2004), one new species of Heterogorgia (Breedy &
Guzman 2005), specimens of the pennatulid Ptilosarcus,
one species of Eugorgia, one of Leptogorgia, and probably
three or four species of Muricea. Several are expected to
represent species new to science (Table 1).
Geographic distribution of Galapagos shallow-water
species is shown in Table 1. In addition to the species in
the table, Muricea galapagensis, a deep-water species (> 50
m) collected in 1938 at Isabela Island (Deichmann 1941),
has not been reported since.
 Although sea pens were believed to have disappeared
from Galapagos following the 1982–3 El Niño event, all
three species have been observed recently at depths below
40 m (S. Banks pers. comm.).
Among the Gorgoniidae, P. dampieri, P. symbiotica and
Leptogorgia alba (Fig. 1) have been found at the northernmost
islands of Darwin and Wolf. A species similar to P. symbiotica
was also found at these islands but its status is not yet
resolved. P. rubripunctata was found mostly at the central
and eastern islands, while a similar species, Pacifigorgia
sp. 2 was found coexisting with P. rubripunctata at Santa
Cruz. P. darwinii (Fig. 2) was found throughout the central
and western archipelago. It is the species with the widest
range, but is not reported for Darwin and Wolf. Eugorgia
Figure 1. Leptogorgia alba, Darwin´s Arch, Darwin Island.
Photograph: CPH.
Figure 2. Pacifigorgia darwinii, Roca Onan, Pinzón Island.
Photograph: Angel Chiriboga.
30 Galapagos Research 66Research Articles
daniana (Fig. 3) was found at Genovesa, Pinzón and
Nameless.
Of the Plexauridae, two of the Muricea spp. are probably
new to science. Muricea sp. 2 comprises three chromotypes
(purple, yellow/orange, and white), found together in
Darwin. M. cf. fruticosa (Fig. 4) is distributed throughout
the archipelago, while Muricea sp. 1 is restricted to the
central and southern archipelago. Heterogorgia hickmani
occurs throughout the central and southern archipelago,
while H. verrucosa has been reported only from Santa Cruz.
No specimens of Adelogorgia telones have been recovered
since the initial report by Bayer (1978).
DISCUSSION
Studies of octocoral diversity at other E Pacific oceanic
islands are scarce; only records from Cocos are available
for comparison, where only three species of gorgonians
have been reported, in shallow waters: Pacifigorgia curta
(Breedy & Guzman 2003), Leptogorgia alba (Breedy &
Guzman 2007) and a new, unnamed species of Leptogorgia.
Only L. alba, which is a widespread species, is present in
both Cocos and Galapagos. The pennatulid Ptilosarcus
undulatus that was reported for Cocos (Deichmann 1941)
needs validation, owing to an inadequate description of
the Cocos specimen. Because Galapagos has a wider range
of biotopes and is much larger than Cocos, its diversity
is higher, at least in shallow waters.
The Galapagos octocoral fauna includes more species
than reported from Ecuador’s mainland coast. The few
published records for the mainland include two species
of Leptogorgia and two of Eugorgia (Bielschowsky 1929),
although many others have been observed in recent
explorations (S. Luna, D. Ruiz, pers. comm.). At present,
all of the thirteen largest islands and many of the smaller
islands of the Galapagos have been searched for shallow
water species of octocorals, but other sites remain to be
explored and new records and new species are expected.
Meaningful comparison of gorgonian diversity in Galapagos,
the Ecuador mainland and other oceanic islands will only
be possible when comprehensive surveys equivalent to
those in the Galapagos are completed.
ACKNOWLEDGMENTS
We are especially grateful to the Charles Darwin Research
Station whose sustained support of CPH’s research over
the years has made possible the collections that formed
a large part of OB’s taxonomic research on Galapagos
octocorals. Although many people assisted in the field,
we are especially grateful to Angel Chiriboga, Bill Ober
and Fred Liss for assistance in sample collection, and the
captain and crew of the Tip Top IV during the 2007
collections. We also are grateful to Jorge Cortés who read
and offered helpful comments on this manuscript. The
authors would like to thank the U.K. Department for
Environment, Food and Rural Affairs’ Darwin Initiative
Project 14-048 Galapagos Coral Conservation: Impact Miti-
gation, Mapping and Monitoring for supporting the 2006–7
expeditions to the northern islands of Galapagos, where
some of the recent specimens were collected.
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Figure 4. Muricea cf. fruticosa, Cuatro Hermanos islets, Islabela.
Photograph: CPH.
June 2009 31Research Articles
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