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( a ) Suape and Gamela Beaches on the Pernam- buco coast, Brazil; ( b ) Suape Bay sample sites. SNP = Suape North Point; SSP = Suape South Point.
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We compared morphology of Palythoa caribaeorum (number of polyps, area, diameter and height) occupying three sites located at different distances from a harbor area and with different environmental conditions, such as sedimentation. Seasonality was also considered by comparing morphology during the wet and dry seasons. GLM analyses showed significa...
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... study area is located off the coast of the state of Pernambuco, Brazil ( Fig. 2) and is char- acterized by extensive linear beachrock forma- tions along the seaboard. The width, length and thickness of these formations vary and most of them become exposed during low tide. Climate is warm-humid, pseudo-tropical (Köppen As'), with a mean annual temperature of 24 °C and 1500-2000 mm yearly rainfall that is concen- ...
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... et al. 2004). In the Suape area, the original Atlantic rain- forest has been largely replaced by sugarcane monoculture. Before the port was built, four rivers (the Massangana, Tatuoca, Ipojuca and Merepe) drained into Suape Bay -an estuary partly isolated from the ocean by an extensive sandstone reef line approximately 3500 m long and 80 m wide (Fig. 2b). Today only the Mas- sangana and Tatuoca rivers continue to drain into the bay. The Ipojuca and Merepe rivers had their connection with Suape Bay interrupted by intensive embankment constructed for the Suape Industrial Port Complex ( Neumann et al. 1998) (Fig. 2b). Overall, more than 600 ha of man- grove forest have been destroyed to ...
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... ocean by an extensive sandstone reef line approximately 3500 m long and 80 m wide (Fig. 2b). Today only the Mas- sangana and Tatuoca rivers continue to drain into the bay. The Ipojuca and Merepe rivers had their connection with Suape Bay interrupted by intensive embankment constructed for the Suape Industrial Port Complex ( Neumann et al. 1998) (Fig. 2b). Overall, more than 600 ha of man- grove forest have been destroyed to build port infrastructure ( Silva et al. ...
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... selected three sites located along the reef line of two beaches, Suape and Gamela. The southern reef limit (SSP = Suape South Point) is directly in front of the port complex and is influenced by the Tatuoca river estuary (Fig. 2b). This reef area has the highest heavy metal con- centration (Mn, Pb, Zn, Cr, Ni) in the state of Pernambuco -a consequence of the harbor's high industrial activity, intensified by continuous dredging ( Chagas et al. 2004). For this reason, SSP has deeper and more turbulent surrounding waters. The northern limit of the same reef (SNP = ...
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... in the state of Pernambuco -a consequence of the harbor's high industrial activity, intensified by continuous dredging ( Chagas et al. 2004). For this reason, SSP has deeper and more turbulent surrounding waters. The northern limit of the same reef (SNP = Suape North Point) is closer to Suape Bay and to the coastal town of Cabo de Santo Agostinho (Fig. 2b). The third site, Gamela Beach (GAM) (Fig. 2a), is a part of an Environmental Protected Area (Guadalupe) with little human presence. The beachrock is approximately 450 m long and 250 m wide. Palythoa caribaeorum populations are distributed throughout reef tops in independ- ent patches of different sizes, and are exposed during low tide, ...
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... harbor's high industrial activity, intensified by continuous dredging ( Chagas et al. 2004). For this reason, SSP has deeper and more turbulent surrounding waters. The northern limit of the same reef (SNP = Suape North Point) is closer to Suape Bay and to the coastal town of Cabo de Santo Agostinho (Fig. 2b). The third site, Gamela Beach (GAM) (Fig. 2a), is a part of an Environmental Protected Area (Guadalupe) with little human presence. The beachrock is approximately 450 m long and 250 m wide. Palythoa caribaeorum populations are distributed throughout reef tops in independ- ent patches of different sizes, and are exposed during low tide, yet protected from wave ...
Citations
... Zoanthid-dominated ecosystems in the Canary Island have so far demonstrated stability for several years once established in dense populations in the substrate López et al., 2020;Moreno-Borges et al., 2022), and not even the recurrent mass mortality episodes of D. africanum Girard et al., 2012;Sangil and Hernández, 2022) have reverted ecosystem state to algal-dominated systems typical of these subtropical latitudes. Probably, available substrate provided by herbivores is crucial for the initial establishment of zoantharians, yet their persistence in dense populations is maintained by positive feedback mechanisms driven by the species competitive biological traits (Acosta et al., 2001;Cen-Pacheco et al., 2014;Costa et al., 2011;Patocka et al., 2015). This is the first study to assess the effects of different zoantharianmacroalgae interactions under controlled laboratory conditions. ...
... Palythoa caribaeorum has a notable growth rate, ranging between 0.015 cm.day -1 to 0.4 cm.day -1 (Suchanek & Green 1981, Mendonça-Neto & Gama 2009, Costa et al. 2011, Silva et al. 2015. The overgrowth strategy is probably one of the major mechanisms adopted by the species to defeat competitors (Suchanek & Green 1981, Bastida & Bone 1996. ...
The space is a limited resource for the establishment of benthic species onconsolidated substrates. Considering the introduction of invasive species, the effects of theinterspecific competitive interaction must be evaluated, once the prevalence of these organismsover native species depends upon a repertory of strategies not fully understanding. Tubastraeacorals became overspread along the Atlantic Ocean, being majorly observed on artificialsubstrates. Palythoa caribaeorum is a native zoanthid with high growth rates, and colonies withshort polyps embedded in the coenenchyma. To study the interaction between Tubastraea spp.and P. caribaeorum, a manipulative experiment was developed in situ in the Todos-os-SantosBay (12ºS, Bahia State). Two species (and respective morphotypes), Tubastraea tagusensis(dendroid) and Tubastraea coccinea (plocoid), were tested. No tissue damage was detected inany Tubastraea sample during the interspecific experiment. P. caribaeorum underwentretraction, mucus deposition and overgrowth, but no statistical difference was recorded. Thestudy of competition between native species and introduced organisms is fundamental tocomprehend how local diversity will be affected.
... Although little is known about what exactly induces changes in the phenotype of zoantharians, some authors claimed that morphological variations in Palythoa and Zoanthus species may be a response to water turbidity (Costa et al., 2011), depth (Kamezaki et al., 2013) or, more generally, to light intensity (Ong et al., 2013). Morphological phenotypic plasticity would facilitate the colonization of a wide variety of habitats and help organisms adapt to changes in their environment (Burnett et al., 1997;Costa et al., 2011;Ong et al., 2013). ...
... Although little is known about what exactly induces changes in the phenotype of zoantharians, some authors claimed that morphological variations in Palythoa and Zoanthus species may be a response to water turbidity (Costa et al., 2011), depth (Kamezaki et al., 2013) or, more generally, to light intensity (Ong et al., 2013). Morphological phenotypic plasticity would facilitate the colonization of a wide variety of habitats and help organisms adapt to changes in their environment (Burnett et al., 1997;Costa et al., 2011;Ong et al., 2013). Reimer et al. (2006b) observed that, due to volcanic ash incorporated into their tissues, samples of Palythoa mutuki (Haddon and Shackleton, 1891) and Palythoa tuberculosa (Esper, 1805) harvested in a volcanic area were darker in colour than samples harvested in non-volcanic areas. ...
Anemone-like animals belonging to the order Zoantharia are common anthozoans widely distributed from shallow to deep tropical and subtropical waters. Some species are well-known because of their high toxicity due to the presence of palytoxin (PLTX) in their tissues. PLTX is a large polyhydroxylated compound and one of the most potent toxins known. Currently, the PLTX biosynthetic pathway in zoantharians and the role of the host or the putative symbiotic organism(s) involved in this pathway are entirely unknown. To better understand the presence of PLTX in some Zoantharia, twenty-nine zoantharian colonies were analysed in this study. All zoantharian samples and their endosymbiotic dinoflagellates (Symbiodiniaceae = Zooxanthellae) were identified using DNA barcoding and phylogenetic reconstructions. Quantification of PLTX and its analogues showed that the yields contained in Palythoa heliodiscus, Palythoa aff. clavata and one potentially undescribed species of Palythoa are among the highest ever found (up to > 2 mg/g of wet zoantharian). Mass spectrometry imaging was used for the first time on Palythoa samples and revealed that in situ distribution of PLTX is mainly located in ectodermal tissues such as the epidermis of the body wall and the pharynx. Moreover, high levels of PLTX have been detected in histological regions where few or no Symbiodiniaceae cells could be observed. Finally, issues such as host‐specificity and environmental variables driving biogeographical patterns of hosted Symbiodiniaceae in zoantharian lineages were discussed in light of our phylogenetic results as well as the patterns of PLTX distribution. It was concluded that (1) the variability of Symbiodiniaceae diversity may be related to ecological divergence in Zoantharia, (2) all Palythoa species hosted Cladocopium Symbiodiniaceae (formerly clade C), (3) the sole presence of Cladocopium is not sufficient to explain the presence of high concentrations of PLTX and/or its analogues, and (4) the ability to produce high levels of PLTX and/or its analogues highlighted in some Palythoa species could be a plesiomorphic character inherited from their last common ancestor and subsequently lost in several lineages.
... In fact, some species are presently expanding their populations, becoming locally abundant under these conditions (Karlson, 1981;Sebens, 1982;Acosta, 2001;Silva et al., 2015;L� opez et al., 2018) and even causing phase-shifts in coral reef ecosystems (Cruz et al., 2016a, b). Intrinsic characteristics of Zoantharia, such as colony plasticity (Karlson, 1983;Costa et al., 2011) and fast growth combined with effective asexual reproduction (Suchanek and Green, 1981;Rabelo et al., 2013;Fadlallah et al., 1984;Acosta and Asbahr, 2000) and their potent palytoxin content (Tubaro et al., 2011) are probably involved in such colonisation success. This study constitutes an example of such population spread outside tropical regions and, to our knowledge, one of the few cases occurring in macroalgae-dominated systems. ...
Global warming is driving changes in the distribution patterns of many species, leading to a general tropicalization and meridionalization of biota. In this context, populations of some marine species are in regression while others are expanding their populations. Such is the case of benthic cnidarians belonging to the order Zoantharia and suborder Brachycnemina, whose populations are able to cause phase-shifts in coral reef ecosystems. Marine assemblages in the subtropical Canary Islands region consist of a combination of both temperate and tropical species, mainly due to the east-to-west seawater temperature gradient that naturally exists throughout the archipelago. This can reach a 2 °C difference (≈23-25 °C east to west in summer months). These biogeographical features make the archipelago a unique location to research into biota reorganisation processes. The aim of this study was to establish a baseline of the distribution and abundance data of zoantharian Brachycnemina populations in the Canary Islands. To elucidate whether these species are potential bioindicators of ocean warming processes, patterns of species distribution and their relationships with the temperature gradient across the archipelago were also evaluated. Results demonstrated that intertidal and subtidal populations of Palythoa aff. clavata and P. caribaeorum, respectively, followed distribution patterns related to the temperature ranges recorded in situ by data loggers. Extensive populations were found in the western islands where seawater temperatures are warmer than the eastern islands. Since biota reorganisation usually produces loss of ecosystem functions, it is essential to establish baseline datasets of climate change indicators and also effective monitoring programmes. These will allow early detection of phase-shifts before they lead to significant changes in ecosystem dynamics.
... La primera abunda en zonas rocosas del mesolitoral aunque con menor frecuencia podemos encontrar colonias aisladas en el submareal somero hasta los 10 metros de profundidad(Simón Otegui, 2015).Por su parte, P. caribaeorum aparece también en zonas intermareales pero es más frecuentemente en fondos submareales pocos profundos, entre 2-10 metros de profundidad, llegando a formar grandes extensiones en ambientes con baja exposición al oleaje y alta luminosidad(Sebens, 1982;Leão, 1996;Acosta et al., 2001). La amplia distribución y alta cobertura de P. caribaeorum es probablemente el resultado de varios factores tales como la plasticidad de la colonia(Karlson, 1983;Costa et al., 2011), su capacidad de adaptación fisiológica(Sebens, 1982), la mezcla de estrategias de reproducción sexual y asexual(Fadlallah et al., 1984;Acosta et al., 2001), su crecimiento rápido(Suchanek & Green, 1981;Rabelo et al., 2015), una fuerte habilidad competitiva(Bastidas & Bone, 1996), y mecanismos antidepredación(Sebens, 1982), además de una alta tolerancia a la variabilidad ambiental(Cooke & Zeeman, 1976;Sebens, 1982;Sorokin, 1991;Rotjan et al., 2006).Considerando las características biológicas inherentes generales de los zoantídeos y en concreto de las especies objeto de este trabajo, junto con el actual aumento en la temperatura del mar se espera una expansión de las poblaciones de dichas especies si continúa la tendencia actual de calentamiento oceánico(Reimer et al., 2008;Reimer et al., 2016). Esta hipótesis está respaldada por datos observacionales recientes de estas especies en las islas Canarias(Simón Otegui, 2015; López et al. en prep.). ...
El calentamiento de los océanos asociado al cambio climático provoca importantes alteraciones en la biota marina. En este trabajo se establece el punto inicial de un programa de seguimiento a largo plazo de dos especies de zoantídeos, Palythoa canariensis y P. caribaeorum, en el intermareal de Tenerife. Se pretende evaluar las variaciones en el crecimiento de estas especies de apetencias tropicales en relación a las oscilaciones térmicas y su potencial como especies bioindicadoras de cambio climático en Canarias. Para ello, se realizó un seguimiento del crecimiento de colonias de ambas especies en diferentes localidades de Tenerife, atendiendo a factores como su orientación en la isla, la estación del año y los regímenes de temperaturas. P. canariensis presentó un patrón de crecimiento estacional diferente entre localidades de estudio, siendo más variable en la vertiente norte, de aguas más frías. P. caribaeorum no registró una estacionalidad en el crecimiento, probablemente porque su localización en las aguas más cálidas de la isla determina que el crecimiento no se vea limitado por la temperatura. Se hace necesario corroborar los patrones observados con un marco temporal de seguimiento más amplio, a fin de concluir sobre la idoneidad de las especies como indicadores de cambio climático.
... Intertidal environments are highly heterogeneous habitats characterized by large fluctuations in several major environmental factors (e.g., temperature, salinity, solar radiation or aerial exposure) (Thompson et al. 2002;Helmuth et al. 2006). Organisms inhabiting these environments are exposed to various stress factors such as desiccation, osmotic stress, extreme temperatures, aerial exposure and food limitation (e.g., Shick and Dykens 1984;Freites et al. 1 3 222 Page 2 of 11 an aggressive competitor for vital resources in intertidal habitats (Mendonca-Neto and da Gama 2009;Costa et al. 2011). Nevertheless, it seems that it is more susceptible to adverse conditions such as aerial sunlight exposure than other zoanthids in the same area (Mendonca-Neto and da Gama 2009;Rabelo et al. 2015), which make this species a good model to explore the biological effects of aerial exposure in symbiotic cnidarians. ...
... Summing up, we hypothesize that intertidal P. caribaeorum colonies present specialized polyps which are adapted to the stressful conditions imposed by aerial exposure (Freites et al. 2002;Kumar et al. 2011), namely regarding the carbon source. These results suggest that this species seems to have a large trophic plasticity in addition to its morphological plasticity (Costa et al. 2011). This strongly indicates that P. caribaeorum is highly adapted to the colonization of heterogeneous habitats such as intertidal environments, possibly explaining the wide distribution of this zoanthid and its success as a competitor in these habitats (Mendonca-Neto and da Gama 2009). ...
The colonization of intertidal habitats is a challenging process. During low tide, many photosynthetic organisms, including symbiotic zoanthids, can be partially exposed to air eliciting significant physiological impairments, which may ultimately dictate the rate of colonization in such environments. Within this context, the present study aims to investigate, for the first time, the effects of air exposure on the fatty acid (FA) content and photobiological parameters of Palythoa caribaeorum, by comparing emerged and immersed polyps, within the same colony, during low tide. Tidal environment did not significantly affect FA percentages, but polyps that were emerged showed lower FA content than the immersed ones. Saturated FA fraction contributed the most to those dissimilarities, followed by the highly unsaturated and polyunsaturated FA fractions. Concomitantly, polyps that were permanently immersed displayed significantly higher values of the maximum quantum yield of photosystem II (F
... The references are numbered according to their order of citation and correspond to: 1 Migotto et al. 1999, 2 Da Silveira and Morandini 2011, 3 Laborel 1970, 4 Pires et al. 1992, 5 Grohman and Peixinho 1995, 6 Rabelo and Matthews-Cascon 2007, 7 Soares et al. 2011, 8 Castro et al. 1999, 9 Amaral et al. 2000, 10 Campos et al. 2005, 11 Bouzon et al. 2012, 12 Swain 2009, 13 Sebens 1977, 14 Kelecom and Solé-Cava 1982, 15 Echeverría et al. 1997, 16 Villaça and Pitombo 1997, 17 De Barros et al. 2000, 18 Acosta 2001, 19 Acosta et al. 2001, 20 MacCord and Duarte 2002, 21 Oigman-Pszczol et al. 2004, 22 Acosta et al. 2005A, 23 Boscolo and Silveira 2005, 24 Pérez et al. 2005, 25 Soares et al. 2006, 26 Acosta and González 2007, 27 Stampar et al. 2007, 28 Chimetto et al 2008, 29 Correia and Sovierzoski 2008, 30 Mendonça-Neto et al 2008, 31 Mendonça-Neto and Gama 2008, 32 Souza et al. 2008, 33 Amaral et al. 2009, 34 Chimetto et al. 2010, 35 Francini-Filho and Moura 2010, 36 Francini-Filho et al. 2010, 37 Azevedo et al. 2011, 38 Chimetto et al. 2011, 39 Segal and Castro 2011, 40 Castro et al. 2012, 41 Costa et al. 2011, 42 Almeida et al. 2012, 43 Longo et al. 2012, 44 Martinez et al. 2012, 45 Melo et al. 2012, 46 Rabelo et al. 2013, 47 De Santana et al. 2014, 48 Rabelo et al. 2014, 48 Longo et al. 2000, 50 Kelmo et al. 2003, 51 Metri and Rocha 2008, 52 Wilke et al. 2008, 53 Wilke et al. 2009, 54 Costa et al. 2014, 55 Cruz et al. 2015A, 56 Cruz et al. 2015B, 57 Soares and Souza 2013, 58 Gasparini and Floeter 2001, 59 Teixeira et al. 2008, 60 Villar et al. 2003, 61 Rohlfs and Belém 1994, 62 Sarmento and Correia 2002, 63 Gherardi 2004, 64 Soares and Sousa 2011, 65 Coelho and Ramos-Porto 1980, 66 Costa Jr. et al. 2000, 67 Ferreira et al. 2001, 68 Costa Jr. et al. 2002, 69 Floeter et al. 2007 c Recorded to BA as Palythoa cf. variabilis d Recorded to SC as Zoanthus sociatus; however specimens are Palythoa grandiflora (analyses of unpublished images, pers. ...
Zoantharia (Hexacorallia) is an order of benthic cnidarians, which are known to play an important ecological role in many marine ecosystems. Although the order has a cosmopolitan distribution, including the tropical southwestern Atlantic, research on Brazilian zoantharian species diversity and distribution patterns is lacking. In order to start addressing this gap, we conducted shallow-water coastal and oceanic island sampling in parallel with an extensive literature review to summarize the knowledge of the order Zoantharia from Brazil. Additionally, mitochondrial 16S ribosomal DNA and cytochrome oxidase subunit I (COI) sequences from specimens were determined to confirm their identity and phylogenetic position within the order. Our results show the presence of at least 13 zoantharian species in Brazilian waters, including first records of Palythoa aff. clavata and Zoanthus aff. pulchellus. Moreover, range extensions were confirmed for Palythoa caribaeorum, P. grandiflora, P. variabilis, Zoanthus pulchellus, and Parazoanthus swiftii. We also present the first report on the distribution patterns for all studied species in Brazil. The current study is expected to provide a baseline for further surveys in the tropical southwestern Atlantic, where Zoantharia species richness is still understudied and therefore very likely underestimated. © 2015 Senckenberg Gesellschaft für Naturforschung and Springer-Verlag Berlin Heidelberg
... However, it is generally difficult to determine which specific parameter(s) might drive the different components of the phenotype (Todd et al. 2001). Morphological characters prone to vary include colony size, shape and weight, polyp diameter and density, and sclerite (minute skeletal elements present in the tissues) size and shape (Chappell 1980;West 1997;Costa et al. 2011). Biometric analyses using these variables can provide insights into biological adaptations. ...
Spatial and temporal shifts in biometric features were examined in three common deep-water pennatulacean corals (sea pens) from the Northwest Atlantic: Anthoptilum grandiflorum, Halipteris finmarchica and Pennatula aculeata. These three species show different morphological characters and adaptations to their environment. Analyses of colony length, ratio of peduncle to colony length, weight/length ratio, polyp size and density as well as sclerite shape, location and abundance indicate that their phenotype is modulated by environmental factors (e.g. food availability, currents and sediment type) and antipredator strategies. Moreover, the three species had different carbon and nitrogen stable isotope signatures that could be explain primarily by their different polyp diameters and colony shapes, suggesting that they rely on slightly different food sources (varying proportions of phytodetritus and zooplankton). Finally, sclerites were found only in H. finmarchica and P. aculeata and are not known to occur in A. grandiflorum, except for minute oval bodies inside the peduncle. The Mg/Ca ratio of sclerites differed between the two species and, for P. aculeata, among types of sclerites, evoking different biomineralization pathways related to their functional roles (structural support or defence). Overall, this study provides new information on the ecology of poorly known species, which are ubiquitous and suspected to play an important ecological role in deep-water ecosystems.
... Brazilian coastal reefs are covered mainly by zoanthids (Oigman-Pszczol et al. 2004, Floeter et al. 2007, Francini-Filho et al. 2013) and the dominant species is P. caribaeorum, which is common in the western Atlantic (Acosta et al. 2005, Francini-Filho et al. 2013). The broad distribution and high cover of P. caribaeorum is probably the result of several factors, such as colony plasticity (Karlson 1983, Costa et al. 2011), physiological tolerance (Sebens 1982), mixture of sexual and asexual reproductive strategies (Fadlallah et al. 1984, Acosta and Asbahr 2000, Acosta et al. 2001), fast growth (Suchanek andGreen 1981, Rabelo et al. 2013), strong competitive ability (Bastidas and Bone 1996), and antipredator mechanisms (Sebens 1982). In addition, P. caribaeorum produces palytoxin (Tubaro et al. 2011), which together with the factors mentioned above, makes this species an aggressive competitor for space in reefs (Suchanek and Green 1981, Acosta et al. 2001, Mendonça-Neto and Gama 2009). ...
... The capacity of reproduction, survival, and substrate cover is directly related to the size of benthic organism colonies (Jackson 1977, Hughes and Cancino 1985, Garrabou 1999, Acosta et al. 2001, 2005). In P. caribaeorum the process of colony fission has been well studied, as well as the action of environmental conditions on polyp morphology, fission and fragmentation rates (Acosta et al. 1998, 2001, 2005, Acosta and Sammarco 2000, Costa et al. 2011). However, it is important to differentiate colony fission (McFadden 1986), which contributes to population size, from the fission of an individual polyp, which contributes to colony growth (Acosta et al. 2005). ...
In Brazilian reefs, zoanthids, especially Palythoa caribaeorum are fundamental for structuring the local benthic community. The objective of this study was to determine the growth rate of P. caribaeorum, and to assess the influence of the site (different beaches), season (dry and wet), location (intertidal or infralittoral zones), and human pressure associated with tourism. For one year we monitored the cover of P. caribaeorum in transects and focused on 20 colonies. We cut off a square (100 cm2) from the central part of the colony and monitored the bare area for four months in each season. The average growth rates varied from 0.015 and 0.021 cm.day-1. The rate was homogeneous in all localities, and there was no influence from colony site, location, or touristic visitation, showing that the growth velocity may be an intrinsic characteristic of the species, with a strong genetic component. The growth rate of P. caribaeorum differed among months, and peaked in the first month after injury. The average cover varied from 6.2 to 22.9% and was lower on the reef visited by tourists. The present study corroborates the hypothesis that P. caribaeorum is important for coastal reef dynamics due to its fast and continuous growth.
... The morphological variation observed within this Palythoa group (Burnett et al., 1997; this study) is a probably result of the 'generalist' nature of this species (Reimer et al., 2006c). In the very similar Atlantic sibling species P. caribaeorum (Duchassaing & Michelotti, 1860) morphological plasticity has been suggested to be an adaptive strategy to different environments (Costa et al., 2011). Recently, environmentally-induced changes in polyp-scale morphology have also been demonstrated in P. tuberculosa (Ong et al. 2013), although no work on cnidae plasticity has yet been undertaken. ...
Zoanthids of the genus Palythoa are common in coral reef environments worldwide, particularly in the intertidal zone. However, their taxonomy remains problematic, resulting in an incomplete understanding of their diversity. Palythoa caesia Dana, 1846 is found in Fiji, Australia, and the Indian Ocean, while P. tuberculosa (Esper, 1805) has been reported from India, the Red Sea, Singapore, Madagascar, and Japan. The lack of obvious characters differentiating the two species, their wide distributions and high levels of intraspecific variation raise the possibility that these species are in fact one. Based on specimens from Australia, the Red Sea, and Japan, we used three DNA markers (mitochondrial cytochrome oxidase I, 16S ribosomal DNA, and the nuclear internal transcribed spacer region of ribosomal DNA) combined with morphological analyses of tentacle numbers, and cnidae to re-examine the identity of these two taxa. Phylogenetic results showed sequences from all specimens for all markers formed one monophyly, and morphological results showed little differentiation between the two putative taxa. Overall, it is apparent these two taxa are the same species, and the senior synonym P. tuberculosa should be used for specimens for the entire Indo-Pacific region.
