Cnidaria: Octocorallia: Gorgoniidae) from Mesophotic Reefs in the Eastern Pacific

BULLETIN OF MARINE SCIENCE. 89(3):735–743. 2013 NEW TAXA PAPER http://dx.doi.org/10.5343/bms.2013.1014 http://zoobank.org/urn:lsid:zoobank.org:pub:E62C6099-A6E3-43E0-8F43-014ED71DA0D5

A NEW SPECIES OF THE GENUS EUGORGIA (CNIDARIA: OCTOCORALLIA: GORGONIIDAE) FROM MESOPHOTIC REEFS IN THE EASTERN PACIFIC

Odalisca Breedy and Hector M Guzman

ABSTRACT Our knowledge of octocoral diversity in the eastern Pacific has been focused on shallow reef habitats, while the fauna occurring in the mesophotic zone from 40 to 150 m is poorly known. A new species of the gorgoniid Eugorgia was recently obtained with a submersible from the Hannibal Bank, a coastal seamount 60 km off mainland Panama and 15 km from Coiba Island. The morphological characters were analyzed and illustrated by light and scanning electron microscopy. Eugorgia siedenburgae sp. nov. can be distinguished from the other species in the genus by its bushy, multiplanar, bicolored colony, and the sclerites colors, composition, and sizes. This new species increases the number in the genus to 13 and contributes to our understanding of the fragile mesophotic biodiversity.

Octocoral diversity surveys in the eastern Pacific region have been focused mainly on shallow environments to 40 m depth (e.g., Williams and Breedy 2004, Breedy et al. 2009, Breedy and Guzman 2012). Consequently, the fauna inhabiting mesophotic habitats from 40 m to >150 m is poorly described and may be at risk due to intensive fishing (see Lesser et al. 2009, Clark et al. 2010). Here, we describe a new species of the gorgoniid Eugorgia recently collected from the Hannibal Bank seamount, Pacific Panama. The genus Eugorgia (family Gorgoniidae) is considered to be exclusively eastern Pacific (from Southern California to Peru), it is found mostly from 10 to 40 m. Eugorgia rubens Verrill, 1868 has the deepest records from 50 to 60 m, obtained mostly from fishing nets or dredging. Eugorgia is characterized by having flabellate to bushy colonies with one or multiple planes. Branching is lateral, partially dichoto- mous, or pinnate-like, often bushy, and combinations of both; branch anastomosis is absent, but pseudo-anastomosis frequently occurs (Breedy et al. 2009). The colonies have a horny axis, which has a narrow cross-chambered central core with a network of organic filaments frequently mineralized with deposits of carbonate hydroxyl apa- tite. The holdfast could be attached to hard substrates, debris, and coarse sand or muddy sediments. Polyps are fully retractile into the coenenchyme, in slightly raised to prominent mounds arranged in series of longitudinal rows, or evenly distributed on the branches. Coenenchymal sclerites are of various types: spindle, disc-spindle, capstan, and the most dominant form that defines the genus is the characteristic double disc. Anthocodial sclerites are rarely found. Color of colonies and sclerites is variable: colorless, yellow, orange, red, violet, brownish, or combinations of these (Breedy et al. 2009). According to the morphological features, the species are pro- posed to form three groups, the daniana-group, the ampla-group, and the monospecific rubens-group (see Breedy et al. 2009). There are seven species of Eugorgia reported for the Pacific coast of Costa Rica and Panama.

Figure 1. Eugorgia siedenburgae sp. nov. (STRI 1227), collection of the holotype, Hannibal Bank, 65 m deep. DeepSee photograph.

Materials and Methods

Study Site and Collection Methods.—Samples were collected in the Hannibal Bank (07°26.194´N, 082°4.508´W), a coastal seamount located 60 km off mainland Pacific Panama. The seamount is an elongated, triangular guyot, 14.4 km long and 7.1 km wide, and ranging in depth from 45 m on rugose areas at the top of the seamount to 416–500 m at the bottom of the steep slope. The bank covers an area of 76 km2. The seamount is geologically complex with fragments of oceanic plate, spreading centers, hotspot traces such as the Cocos, Malpelo, and Carnegie Ridges together with sedimentary units typical in nearshore to shelf areas (Cunningham et al. in press). The bank is unaffected by seasonal upwelling and is part of the Coiba National Park and a World Heritage Site, administered as special management fishing area encompassing 1781 km2. Several specimens were observed and photographed from the submersible DeepSee (UnderSea Hunter Group), and collected using a mechanical arm (Model Orion, Shilling Robotics USA) in March 2012 during a Smithsonian Tropical Research Institute expedition (Fig. 1). All specimens were deck-photographed and dried and/or preserved in 95% ethanol. Additional specimens were used for the description of the species, collected by bottom trawl- ing from Santa Elena Bay (10°55.155´N, 085°48.573´W), a contrasting seasonal upwelling area located on the north Pacific coast of Costa Rica. Morphological Study.—For microscopic study, specimens were prepared for light microscopy and SEM following the protocol described in Breedy and Guzman (2002) and for assessment of characters we followed Verrill (1868) and Breedy et al. (2009). Morphological characters of colonies and sclerites are presented in Table 1, and comparison with the type material of the related taxa in the genus. The holotype and paratypes from Panama are depos- ited in the Smithsonian Tropical Research Institute (STRI) and paratypes from Costa Rica at the Museo de Zoología, Universidad de Costa Rica (MZUCR, former UCR). Terminology used in descriptions mostly follows Bayer et al. (1983), Breedy and Guzman (2002), and Breedy et al. (2009). breedy and guzman: a new eugorgia from mesophotic reefs 737

Results

The new species was determined through the comparison of its morphological characteristics with the closest taxa (see Table 1).

Class Anthozoa Ehrenberg, 1831 Subclass Octocorallia Haeckel, 1866 Order Alcyonacea Lamouroux, 1812 Family Gorgoniidae Lamouroux, 1812 Genus Eugorgia Verrill, 1868 Eugorgia siedenburgae new species (Figs. 1–4)

Holotype.—STRI 1227, Hannibal Bank, Coiba Island, Gulf of Chiriquí, Panama, 63 m, DeepSee Dive 1553, 10 March, 2012. Paratypes.—Panama: STRI 1221–1222, 1232, 1239, 1242, 1246, Hannibal Bank, Coiba Island, Gulf of Chiriquí, 63 m, DeepSee Dive 1553, 10 March, 2012. Costa Rica: MZUCR 2272, 2276, ethanol preserved, trawl 46, 54.2 m, Y Camacho, 9 July, 2005; MZUCR 2278, dry, trawl T20, #1, Bahía Santa Elena, R/V Urraca Expedition, trawl 20, #1, 50–52 m, Y Camacho, 9 July, 2005; MZUCR 2280, dry, Bahía Santa Elena, R/V Urraca Expedition, trawl 4, #3, 50–52 m, Y Camacho, 9 July, 2005; MZUCR 2281, dry, Bahía Santa Elena, Guanacaste, Costa Rica, R/V Urraca Expedition, trawl 4, #15, 50–52 m, Y Camacho, 9 July, 2005. Diagnosis.—Bushy, stout colony, profusely branched in several planes, branching irregularly pinnate, subdividing up to 10 times, pseudo-anastomosis present (Fig. 2A), prominent polyp-mounds up to 0.70 mm tall, arranged in two or three lateral rows and sparsely and irregularly distributed (Fig. 2B). Colony bright pink to reddish orange fading toward the tips to orange or pale pink (Fig. 2A,B). Sclerite colors: different combination of red, pink, light yellow, and bicolored (Fig. 2C). Spindles and disc spindles up to 0.11 mm, double discs and capstans mostly 0.07–0.075 mm, scant complete double discs up to 0.07, and crosses around 0.07 × 0.07 mm. No anthocodial rods. Description.—Holotype 42 cm tall, and 26 cm wide, bushy colony, profusely branched, growing in several planes (Fig. 2A). Branching irregularly pinnate, several pseudo-anastomosis occurs in branchlets and branches. Main stem 8 mm diameter, slightly compressed, and short, 1.5 cm long arising from a conical holdfast, 3.4 cm wide and 2.4 cm tall. Main stem subdividing in multiple branches, 2.0–3.0 mm diameter emerging at angles of 30°–45° and producing secondary branches giving off thin branchlets, 1–1.5 mm diameter, including polyp-mounds. Branchlets irregularly arranged and closely spaced, separated 1–15 mm, and giving off 1–3 lateral, secondary branchlets, which are of same thickness and closely placed. Branchlets 2–30 mm long. Branching up to 10 times. Unbranched terminal twigs blunt, and reach up to 30 mm long (Fig. 2A,B). Polyps white. Polyp-mounds prominent, up to 0.70 mm height and 1.0 mm in diameter, arranged in two or three lateral rows along the branchlets,

738 BULLETIN OF MARINE SCIENCE. VOL 89, NO 3. 2013 Color rings Color

y no no no no

sclerite color sclerite

Coenenchymal Coenenchymal p

p,y r, y r, y r, y Bicolor colony colony Bicolor

X no no no no

colony Color of of Color r p

p,o do, r do, r Anth. rods Anth. 0.08

not found not found not found not found Crosses no

0.06 × 0.06 ×

0.078 × 0.071 0.075 × 0.065 Bent spindles spindles Bent

X X X no no ). The characteristics are based on based are characteristics The ). rubens -group (genus Eugorgia Spindles

0.11 0.11 0.10 0.13 0.13 Disc-spindle

0.11 0.10 0.13 0.13 Capstans

0.07 0.07 0.07 0.07 Double disc Double

0.08 0.07 0.07 0.08 0.07

double disc double

group and with the with daniana- group and Complete Complete

no no

0.067 0.065 0.043

distribution Polyp Polyp

irr irr irr reg reg

, within the , within

length length Branchlet Branchlet

2–30 1–10 2–30 1–15 6–30

diameter diameter Branchlet Branchlet

1.5–2.0 1.0–1.5 1.0–1.5 1.0–1.5 1.0–2.5

distance Branchlet Branchlet Eugorgia siedenburgae siedenburgae Eugorgia

6.0–20.0 1.0–4.0 1.0–15.0 1.0–4.0 1.5–8.0

of branching of

Max number number Max 5 7 7 6

type

Branching Branching lb

irr-pi irr-pi irr-pi irr-pi Colony growth Colony bu pla pla pla spa E. rubens E. multifida sp. nov. E. siedenburgae E. daniana E. aurantiaca Colony growth: bu, bushy; pla, planar growth, flabelliform; spa, sparse growth. irregularly pinnate; lb, laterally branched Colony branching: irr-pi, arrangement mostly in irregular longitudinal rows; reg, regular rows. Polyp distribution: irr, Colors: dark orange (do), (o), pink (p), red (r), yellow (y). Table 1. Comparative features of the new species, of the features 1. Comparative Table the holotypes and lectotypes (Verrill 1868, Breedy et al. 2009). Sclerite sizes represent the maximum length found in samples. Measurements are given mm. the holotypes and lectotypes (Verrill Species breedy and guzman: a new eugorgia from mesophotic reefs 739

Figure 2. Eugorgia siedenburgae sp. nov. (STRI 1227), holotype. (A) entire colony; (B) detail of branches, photographs by S Mattson; (C) sclerites. and sparsely and irregularly distributed along the thick branches (Fig. 2B). Holdfast and main branches devoid of polyps. Colony of a bright pink color fading towards the tips to an orange hue (Fig. 2A,B). Color of living colony persisted regardless of dry or ethanol preservation (Figs. 1, 2A,B). Sclerites of coenenchyme red, pink, light yellow, and bicolored (Fig. 2C). Mostly double discs up to 0.076 mm long and 0.05 mm wide (Fig. 3D); very few complete double discs up to 0.067 mm long and 0.046 mm wide (Fig. 3D, right, last row), and capstans up to 0.074 mm long, and 0.045 mm wide (Fig. 3C). Crosses 0.078 × 0.071 mm (Fig. 3B). Spindles and disc-spindles not abundant, up to 0.11 mm long and 0.04 mm wide, with 4–5 whorls of warty tubercles, the ends acute, blunt, or both (Fig. 3A). No anthocodial sclerites present in samples. Variability.—Paratypes are complete colonies and fragments from 7–28 cm tall to 4–24 cm wide. They closely match the characteristics of the holotype. The branching style ranges from the holotype, which is ascending with few branching planes, to the paratype MZUCR 2278, which is bushy expanding in multiple planes (Fig. 4A). Most of the examined colonies grow in multiple planes mostly parallel to the main axis, 740 BULLETIN OF MARINE SCIENCE. VOL 89, NO 3. 2013

Figure 3. Eugorgia siedenburgae sp. nov. (STRI 1227), holotype. (A–D) coenenchymal sclerites. breedy and guzman: a new eugorgia from mesophotic reefs 741

Figure 4. Eugorgia siedenburgae sp. nov. (A) paratype MZCR 2278; (B) paratype STRI 1221, photograph by C Gómez. and some branches pseudo-anastomose to produce complex branching arrangement. Complete colonies branch 7–10 times. The color could be darker and without evident orange tips, just slightly faded hues of pink or light yellow toward the ends (Fig. 4B). This variation could be found in either small or large colonies. Sclerites are like those in the holotype, orange, pink, and bicolored, but some variation is found in the color proportions, e.g., few orange or yellow sclerites. Shapes and sizes agree with the holotype. Habitat.—It was found patchily distributed on isolated rocks and coarse sand at the type locality. A big basket star was attached to the holotype at the time of collection (Fig. 1). Some specimens from Santa Elena Bay retained the holdfast, and are attached to slab fragments of sedimentary rocks, other species of octocorals were collected in the same trawls. Etymology.— Joan S Siedenburg is a science enthusiast, explorer, and a longstand- ing friend of the Smithsonian Tropical Research Institute. Through her philanthropy, encouragement and passion for learning, she has inspired many scientific colleagues in Panama. This new species name recognizes Siedenburg’s special interest in deep- sea exploration and her appreciation of tropical life. Distribution.—Known from the mesophotic reefs in type locality in Panama and Santa Elena Bay, Costa Rica; 50–63 m depth.

Discussion

Twelve species have been reported in the genus, seven from Costa Rica and Panama (Breedy et al. 2009). The daniana-group is composed of three species, Eugorgia daniana Verrill, 1868, Eugorgia aurantiaca (Horn, 1860), Eugorgia multifida Verrill, 1870, and the monospecific rubens-group by Eugorgia rubens Verrill, 1868. One species of the daniana-group occurs in Costa Rica, and two in Panama (E. daniana and E. aurantiaca, although a dubious locality of the latter). There are no records 742 BULLETIN OF MARINE SCIENCE. VOL 89, NO 3. 2013 of E. multifida either in Costa Rica or in Panama. Eugorgia rubens occurs in Costa Rica, presently reported only from one locality, Murciélago Islands in Santa Elena Peninsula (Breedy et al. 2009), records are absent for Panama. The new species is closer to the daniana- or the rubens-group according to the general definition of the groups: daniana-group include species similarly colored, irregular pinnate branching up to seven times, with prominent polyp mounds and share the presence of yellow and red sclerites in the coenenchyme; the rubens-group includes a species, irregular pinnate branching up to five times, with prominent polyp mounds, and all sclerites pink (Breedy et al. 2009). It is important to note that the type of branching in both groups is defined as irregularly pinnate, because true regular pinnate branching does not occur in Eugorgia (Breedy et al. 2009; Table 1). All species in both groups and the new species have stout branches, irregularly pinnate branching, prominent polyp-mounds, polyp arrangement crowded, and the dominant type of sclerite is the incomplete double disc. Eugorgia siedenburgae sp. nov. can be distinguished from the other four species by the following features. Firstly, E. siedenburgae sp. nov. has a bushy, profusely branched colony growth. In the daniana-group, colony growth is mostly flabellate. In E. rubens it is elongated, with branches and branchlets sparsely placed, 6–20 mm apart, and branching in one plane. Secondly, E. siedenburgae sp. nov. colony is a bright pink color with characteristic lighter tips. Eugorgia rubens has a bright pink colored colony, also, but the tips are not of a different hue, they are even. Additionally, E. siedenburgae sp. nov. differs from the other Eugorgia species in many other aspects, especially in the polyp distribution, maximum number of branching, and color and dominance of sclerite types (Table 1). The new species shares more morphological characteristics with the daniana-group than with E. rubens, but it coincides with E. rubens in the bathymetric range of occurrence, that is not common in the genus. Interestingly, the new species is very similar to Leptogorgia regis Hickson, 1928 in external morphology, especially in color and colony shape, and this species was also collected in the same trawls. For the time being E. siedenburgae will be placed in a new separate group of Eugorgia. This new species increases the number of the genus to 13, and contributes to the knowledge of the mesophotic zone biodiversity, habitat considered as potential refuge for species in the face of reef decline (Bongaerts et al. 2010).

Acknowledgments

We are grateful to anonymous reviewers for critical improvements of the manuscript. We thank crew members of the DeepSee submersible and the MV HunderSea Hunter for making possible the coral collections in Hannibal Bank, and Y Camacho and R Vargas (MZUCR) for collecting specimens during the July 2005 STRI’s R/V Urraca Expedition. We thank S Mattson and C Gomez (STRI) for specimen pictures. The expeditions and laboratory work were partially funded by the International Community Foundation, the Smithsonian Tropical Research Institute, the Instituto de Investigaciones Científicas y Servicios de Alta Tecnología de Panamá (INDICASAT), the Siedenburg family, the Mission Blue’s Sylvia Earl Alliance, and the Vicerrectoría de Investigación (A9072, B2142 projects), Universidad de Costa Rica. breedy and guzman: a new eugorgia from mesophotic reefs 743

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Date Submitted: 6 February, 2013. Date Accepted: 30 April, 2013. Registered Online: 19 July, 2013.

Addresses: (OB) Centro de Investigación en Ciencias del Mar y Limnología, Centro de Investigación en Estructuras Microscópicas, Universidad de Costa Rica, San Pedro, P.O. Box 11501-2060, San José, Costa Rica. (HMG, OB) Smithsonian Tropical Research Institute, P.O. Box 0843-03092, Panama, Republic of Panama. Corresponding Author: (OB) Email: .