Ocurrence of the sea anemone Telmatactis panamensis (Verrill, 1869) (Cnidaria: Anthozoa: Actiniaria) at Isla del Coco National Park, Costa Rica

: The sea anemone fauna of Isla del Coco National Park (also known as Cocos Island Nacional Park), Pacific Costa Rica is poorly known. In the present work we report the first occurrence of the species Telmatactis panamensis . Individuals of this sea anemone (n=24) were collected at Chatham Bay intertidal and at 15m depth in Punta Ulloa, in both cases attached to rocks; during the expedition UCR-UNA-COCO-I in April 2010. We provide photographs of live individuals, external anatomy and an inventory of cnidae of the studied specimens. Possibly this species is extended to greater depth as observed by other authors in the Galápagos Islands.

Cocos Island (Isla del Coco, Costa Rica) is one of the oceanic islands in the Eastern Tropical Pacific.The marine fauna of this island have been the subject of scientific interest especially for the biogeographic relevance and biodiversity (Breedy & Cortés 2008).This island has been the target of numerous expeditions to explore the island's species richness (Cortés 2008); notwithstanding some groups like the sea anemone fauna are practically unknown.The only record of a sea anemone is the species Telmatactis cricoides (cited as T. americana) (Cortés 1996(Cortés /1997)), based on a photographic record (Bradley & Ireland 1993), but its identification is doubtful.During the expedition UCR-UNA-COCO-I to Isla del Coco National Park in April 2010 we sampled many sites and collected many individuals of sea anemones, both from the intertidal and deeper zones.This sampling allowed us to identify the species T. Panamensis, this being the first record of a sea anemone based on collected individuals from this island.

MATERIAL AND METHODS
The individuals were collected by hand from the intertidal zone at Bahía Chatham (5º32'52"N 87º02'32"W) and by SCUBA dives at Punta Ulloa (5º33'05"N 87º02'06"W), Isla del Coco National Park, Costa Rica; during the expedition UCR-UNA-COCO-I in April 2010.Individuals were anesthetized by the addition of crystals of magnesium chloride, and preserved in 5% formalin and later in ethanol 70%.The external characters of live specimens were observed in the field and also in preserved material in the lab.The internal anatomy was studied by dissections under the stereoscopic microscope.The cnidae was analyzed using a Zeiss Axiolab Microscope with micrometric eyepiece at a magnification of 1000x (oil immersion).Terminology of cnidae follows England (1991).The current classification of sea anemones, synonymy and the taxonomic status were cross-checked with the electronic database "Hexacorallians of the World" (Fautin 2011).Phellia rapanuiensis Carlgren, 1922Carlgren, (1920)), p. 153-156.

Characteristics of studied specimens
In the intertidal zone of Bahía Chatham 24 small specimens were collected under rocks during low tides, while at Punta Ulloa six individuals under rocks were sampled at 15 m depth (Fig. 1) during two dives.After preservation most of them retracted their tentacles but remained the column extended.The column diameter varies between 0.3cm and 2cm, and height from 0.4cm to 2.3cm in preserved state.Scapus wrinkled brown/orange, thick-walled Photograph by Jaime Nivia.
scapulus (Fig. 2).Acontia may be emitted through scapus and was observed in some of the collected individuals (both live and preserved).Actinopharynx paler orange than column; two symmetrical siphonoglyphes, each have white marking at its intersection with oral disk.Oral disk tentacle-free in central zone.
Digitiform tentacles reddish brown with a proximal white crossband and swollen at their end, internal longer than external.Tentacles from 44 to 79.Those of the primary and secondary cycles much better developed than the others.In Table 1 the size and distribution of cnidae is detailed.The cnidom is composed by spirocysts, basitrichs, microbasic p-mastigophores and microbasic amastigophores.

DISCUSSION
The sea anemone T. panamensis is a new record for Isla del Coco National Park (Costa Rica).It is a common sea anemone in the intertidal of Bahía Chatham and Punta Ulloa at 15m depth, usually attached under rocks, but can also be found attached to large cobbles or shells as was observed by Fautin et al. (2007) in specimens from the Galápagos Islands.Bradley & Ireland (1993) in their photo guide illustrate an specimen of T. cricoides from Isla del Coco National Park (Cortés 1996(Cortés /1997)), but this record is based on a photo and no data are provided on its location, depth or anatomical characteristics, being therefore uncertain.
The anatomical characteristics of studied specimens from Isla del Coco National Park agree very well with the description of T. panamensis by Carlgren (1951) and Fautin et al. (2007), therefore we assigned the analyzed individuals to this species.Doumenc et al. (1989)  Photograph by Jaime Nivia.

in his work on variability of Telmatactis
provide a worldwide inventory of this speciesrich genus and conclude that most of species of Telmatactis are entirely littoral.However, Fautin et al. (2007) found that T. panamensis extends much deeper, while Wirtz (1996) mentioned a range of 0-62m for T. cricoides; in this way it is probable that population of T. panamensis at Isla del Coco National Park may also extend deeper and also to other sites around the island, which may be verified in future expeditions.

ACKNOWLEDGMENTS
We are grateful to Jaime Nivia for the images of T. panamensis that illustrate this paper and to Rodrigo ('Yoyo') Roesch for helping us sampling.To Programa de Promoción de la Universidad Argentina (PPUA) and CONICET for granting FHA to visit CIMAR (UCR) during 2009 and 2010.The expedition to Isla del Coco National Park was funded by the Consejo Nacional de Rectores de las Universidades Públicas (CONARE), with additional support by CIMAR and the Undersea Hunter Group.

Fig. 1 .
Fig. 1.Individual of Telmatactis panamensis from Punta Ulloa showing the oral disc and tentacles.Photograph by Jaime Nivia.
n: total number of capsules measured.N