Linckia Laevigata Research Articles

Pemantauan Kepadatan Megabentos Target Pada Terumbu Karang di Perairan Leato Selatan Kecamatan Dumbo Raya Provinsi Gorontalo

Megabenthos target associated with coral reefs include spiny starfish, blue starfish, sea urchins, sea cucumber, clams, Drupella spp., trocha snail, and lobsters which is ecologically used as an indicator for monitoring the healt condition of coral reefs and is benefical for the community’s economy.The aim of this research is to determine the density level and distribution pattern of megabenthos target on coral reefs in the waters of South Leato, Dumbo Raya Subdistrict, Gorontalo Province. Method used in collecting megabenthos data is with Bentos Belt Transect. Observation results show that the megabenthos target found in South Leato waters were seven types consisting of sea cucumber, clams, trocha snail, spiny starfish, Drupella spp., sea urchins, and blue starfish. The megabenthos target density range values obtained are 0,007 – 0,435 ind/m2, and for morisita index values ranging 0 - 0,6655 id with the distribution pattern of the megabenthos target found all being unifom.

Keanekaragaman dan Kelimpahan Bintang Laut Di Daerah Pesisir Dusun Pandanan, Kecamatan Sekotong Barat, Kabupaten Lombok Barat

Sea stars have morphological characteristics that are radially symmetrical, have 5 (five) or more arms, do not have a skeleton and move freely using tube legs. Sea stars not only function as litter cleaners in the waters, but are also utilized as food processing and handicraft materials. The study aimed to determine the diversity and abundance of sea star species in the coastal area of Pandanan Hamlet, West Sekotong, West Lombok Regency. This study used the belt transect method. All starfish found in the transect recorded the type, number, and habitat characteristics. The results found 6 species of starfish from 4 families namely Echinasteridae, Archasteridae, Ophidiasteridae, and Oreasteridae. The six species are Henricia sp., Archaster typicus, Linckia laevigata, Culcita sp., and Pentaceraster sp. The diversity index (H') has a value of 0.3 - 1.7, the uniformity index (E) is 0.5 - 0.9, and the dominance index (C) ranges from 0.2 - 0.8. The highest abundance in the species Linckia laevigata with a value of 571 ind/ha (station 1) and 333 ind/ha (station 1), while the lowest abundance in the species Pentaceraster sp. 33 ind/ha. All starfish were found to be associated with seagrass plants except Pentaceraster sp.

Type Abundance and Relative Abundance of Macrozoobentos in the Intertidal Zone of Marabatuan Island, Kotabaru, Indonesia

The structure of macrozoobenthos communities plays a crucial role in aquatic ecosystems because most of them are in the second or third trophic level. Components of macrozoobenthos community structure include species and abundance, species diversity index, species uniformity index, dominance index. The research aims to analyze species abundance and relative abundance of macrozoobenthos in the intertidal zone of Marabatuan Island, Kotabaru, Indonesia. The research location is on Marabatuan Island, Pulau Sembilan District, Kotabaru Regency, South Kalimantan Province. The highest relative abundance (KR) was at station 3, namely the species Ophiocoma erinaceus, from the Asteroidea class, the second highest value was at station 2 with the species Holothuria atra and at station 1 of the same species, namely Holothuria atra from the Asteroidea. The lowest relative abundance was at station 1 of the Linckia laevigata species. The Diversity Index (H') of macrozoobenthos at all stations is in the medium criteria.

Antibacterial Potency of Sea Star Linckia laevigata Extract Against Selected Pathogenic Bacteria

The sea star (Asteroidea) is reported to have the potency to be a source of antimicrobial agent. An exploration study was conducted to reveal the potency of antibacterial bioactive of sea star from Maluku waters. This study aimed to determine the bioactive compounds of the Linckia laevigata extract and their antimicrobial activity. The results of qualitative phytochemical test showed that the L. laevigata extract contains flavonoid and saponin. The antimicrobial activity of the L. laevigata extract was demonstrated by an inhibition zone diameter of 29.5 mm against Enterobacter aeuregens and 22.1 mm against Clostridium botulinum. The L. laevigata extract has been proven to have antibacterial activityagainst food pathogenic bacteria.

Kepadatan Megabentos pada Wilayah Konservasi Perairan di Sekitar Kabupaten Kupang, Nusa Tenggara Timur, Indonesia

The Sawu Sea National Marine Park is a marine conservation area in East Nusa Tenggara Province that is known for its high marine biodiversity. The coral reef ecosystem in this conservation area is home to ecologically and economically important megabenthic organisms. Megabenthos are important regulators of marine ecosystems, acting as indicators of coral reef health. However, information on the types and densities of megabenthos in this conservation area is scarce. Research on megabenthos is critical for assessing coral reef health and informing conservation strategies. The aim of this study is to collect baseline data on megabenthos in the Sawu Sea National Marine Park waters surrounding West Kupang and Semau. The Benthic Belt Transect method was used to collect data at six locations throughout the marine park. The information was examined for species composition and density. To assess differences and relationships between locations and megabenthic categories, statistical tests such as Kruskal-Wallis and Pearson's correlation, as well as the Morisita index, were used. Four of the eight target megabenthic categories were identified in the study, with blue starfish and giant clams being the most abundant. There was no statistically significant difference in megabenthic density across locations or ecological and economic categories. The research uncovered potential habitat preferences among various megabenthic categories. The presence and distribution of megabenthos in the waters of this marine park provide important information about the health of coral ecosystems. These findings can help guide conservation efforts.

Echinoderms as a Bioindicator of Water Quality of Weda Waters, Central Halmahera District

Echinoderms are deposit feeders that digest most of the sediment. Echinoderms are also good aquatic bioindicators, because Echinodermata are relatively calm or have low mobility, so they are highly influenced by environmental factors. This study aimed to determine the community structure of Echinoderms and their distribution relationship with several aquatic physico-chemical factors. Echinodermata sampling was carried out using the belt transect method using three stations. Data were collected in the form of the number of echinoderms in the transect and physico-chemical parameters of the waters including temperature, salinity, turbidity, pH, dissolved oxygen, ammonia, nitrite, and nitrate. From the results of research at three station points in the waters of Weda waters, 9 species of Echinodermata were found, namely Protoreaster nodosus, Linckia laevigata, Culcita novaeguineae, Diadema setosum, Diadema savigny, Echinometra mathaei, Tripneusteus gratilla, Holothuria atra, Holothuria edulis which were grouped into 3 classes, 4 orders, 6 families, and 7 genera with a total of 139 individuals. The diversity index of Echinodermata in Weda waters was classified as moderate with an average value of 1.05, the uniformity index was classified as moderate with an average value of 0.56, and the average dominance index value was 0.28 meaning that no species dominated

Asteroidea in the Timbul Bone Labunta Sand Waters, Buton Tengah, Southeast Sulawesi

This study aims to determine the community structure of starfish (Asteroidea) at three observation stations, namely sandy substrate, sandy substrate dominated by seagrass, and sandy substrate dominated by coral reefs in Pasir Timbul Bone Labunta waters. Sampling was carried out in April-May 2023. The indicators in this study are the species abundance index, diversity index, uniformity index, and dominance index. This type of research is a type of quantitative descriptive research. Determination of stations using purposive sampling technique, namely sampling based on substrate conditions and the presence of starfish (Asteroidea). The results of data analysis are presented in the form of figures and tables. The results showed that there were 4 species of starfish in the Asteroidea class, namely Protoreaster nodosus, Linckia laevigata, Archaster typicus, and Culcita novaeguineae. The diversity index at all observation stations showed a moderate category. The uniformity index at all observation stations shows a high category. The dominance index of Protoreaster nodosus, Linckia laevigata, Archaster typicus, and Culcita novaeguineae at all stations showed a moderate category.

KOMPONEN SENYAWA BIOAKTIF EKSTRAK BINTANG LAUT Protoreaster nodosus Dan Linckia laevigata DENGAN METODE MASERASI

Background : One type of species from the class Asteroidea phylum Echinodermata, namely sea stars. Approximately 6000 species from the Phylum Echinodermata and all live in the sea. The use of starfish by the community is still very limited, where it is only used as a food source, even though starfish can also be used as a source of bioactive compounds that are more economically valuable so that they can be used for development in the food and health sectors. This study aims to determine the content of bioactive compounds from the extracts of sea stars Protoreaster nodosus and Linckia laevigata. Methods: Samples were obtained from Waisarisa waters on Seram Island, analysis was carried out at the Biochemistry Laboratory, Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Pattimura. The parameters tested in this study were phytochemical tests which included flavanoid tests, saponin tests, steroid tests, tannin tests and phenolic tests. The extraction technique was carried out by maceration with ethanol solvent. Results: The results of the phytochemical test of the starfish extract Protoreaster nodosus which had positive results in the phytochemical test were tannins, phenolics and saponins. While the test results on the Linckia laevigata starfish extract which had positive results found bioactive flavonoids and saponins. Conclusion: The results of the phytochemical screening test of Protoreaster nodosus star extract have 3 bioactive components namely flavonoids, tannins, phenolics and saponins.

Megabenthos monitoring in Ternate, North Maluku

Several megabenthos groups have important economic and ecological values- also play an important role in the condition and stability of coral reef ecosystems. The important role of this megabenthos group makes it a potential object as an indicator to assess coral reef health. This study aimed to determine the condition of coral reefs by monitoring the megabenthos. The targeted megabenthos in this study consisted of eight groups (Holothuria sp., Diadema sp., Blue Starfish, Tridacna spp., Drupella, Trochus niloticus, Acanthaster planci, and Lobsters). Data collection was carried out in Ternate Waters at 14 stations using the Benthos Belt Transect method. The analysis was carried out by examining the presence and the number of species, distribution and density of each station, density of each type of megabenthos, and ecological indices (dominance index, diversity index, and evenness index). The results of the study found a total of 375 individuals. The group of megabenthos species that were always found at each station was coral polyp-eating snails (Drupella). On the other hand, Acanthaster planci and lobster were groups of megabenthos species found only at a few stations. Overall, Drupella was the most dominant type of megabenthos during observation, which may be related to overfishing at that location. Several groups of fish were natural predators of Drupella. Their numbers in the wild are decreasing due to overfishing. The dominance that occurred during observations was closely related to the health condition of coral reefs and the diversity of coral species as the habitat of megabenthos.

Chemoenzymatic Total Synthesis of the Neuritogenic Echinoderm Ganglioside LLG‐5 and Related Analogues

AbstractLLG‐5 1 is a Neu5Gc8Me‐containing echinoderm ganglioside (EG) isolated from starfish Linckia laevigata. It showed neuritogenic activity toward the rat adrenal pheochromocytoma cell line PC‐12. The first chemoenzymatic total synthesis of the trisialoganglioside LLG‐5 1 has been accomplished by utilizing a convergent [2+3] coupling between a Neu5Gc8Meα(2→5)Neu5Gc‐linked disialoside and a C5‐amino GM3 ceramide, Neu5NH2(2→3)Galβ(1→4)Glcβ‐Cer. A photoactivatable lactosyl phytosphingosine bearing a sulphonate moiety was developed to permit aqueous buffer solubility of the hydrophobic glycolipid acceptor for enzymatic α(2,3) sialylation. In addition, the synthetic route is flexible, allowing non‐natural LLG‐5 analogues in native lengths with or without modification at C8 of the terminal Neu5Gc and/or N‐acyl component, further expanding the diversity of LLG‐5 structures that could be achieved. The developed synthetic strategy may enable access to other EGs.magnified image

KONDISI LAMUN DI PERAIRAN DUSUN ORY PULAU HARUKU KABUPATEN MALUKU TENGAH

Research on the condition of seagrass communities in the waters of Ory village is important to do as a basis for management strategies and data on seagrass meadow conditions. The purpose of this study is to find out the current seagrass conditions (2021) and to find out the structure of the seagrass meadow community formed and the biota associated with seagrass in Ory waters. This research was conducted in June-August 2021 in the waters of Ory village of Haruku Island, Central Maluku District. The sampling technique in this study is based on the use of the square transect line method. Seagrass sampling is done at low tide using a square of 0.5 x 0.5 m with the size of each plot of 0.1 x 0.1 m as much as 25 plots. The data analysis method for occurence frequency calculation, type coverage, while to know seagrass conditions. Based on the results of the study, there are 5 types of seagrass in the waters of Ory village, namely Thalassia hemprichii, Enhalus acoroides, Cymodocea rotundata, Halophila ovalis, and Halodule pinifolia. The density value of seagrass in the waters of Ory village is 322 shoots / m2 (very tight), the frequency of Enhalus acoroides species is more widespread than other types, and the covering value of seagrass is 98.45% (good, healthy / rich). The highest INP is in the Enhalus acoroides, and the biota species associated with seagrass are A. granosa, Linckia laevigata, P. nododsus, and Holothuria scabra

Studi Karakterisasi Morfologi Asteroidea di Pesisir Pantai Gili Gede Kabupaten Lombok Barat

Asteroidea is one of the fauna diversity in the Gili Gede area which plays an important role in maintaining the coastal ecosystem. This study aims to provide information on the morphological characterization of Asteroidea on the coast of Gili Gede which is packaged in the form of a practical assistance book for Invertebrate Systematics. The subject of this research is Asteroidea from Phylum Echinoderms. The object of this research is limited to studies on morphological characterization studies of Asteroidea. This is a descriptive exploratory research and used the cruise method by exploring the coastal area of ​​Gili Gede at a predetermined point based on habitat. Data collection techniques are observation and documentation. The measured microclimate parameters (salinity, temperature and humidity). Sampling was carried out in Gili Gede and morphological identification at the Biology Laboratory, FSTT, Mandalika University of Education. Based on the identification results, the identified asteroids were Protoreaster nodosus (6 individuals), Linckia laevigata (19 individuals) and Echinaster luzonicus (3 individuals). Protoreaster nodosus and Echinaster luzonicus were found in seagrass habitats while Linckia lavigata were found in sandy substrate habitats and coral reefs. Based on the morphological identification observed (color, body circumference, arm length, madreporite, central canal circumference and spicules). It was found that Protoreaster nodosus had white and black color on the spicules and the ends of the arms, massive body circumference; Linckia laevigata is blue in color and non-massive in circumference; Echinaster luzonicus is black on the dorsal and orange on the ventral side with a non-massive body circumference; There is one madreporite in each specimen. Based on the results of the validation of the assistance book, it shows that it is very valid (obtaining a score of 85) and is suitable for use by students as a source (reference), especially the types of Protoreaster nodosus, Linckia laevigata, Echinaster luzonicus.

Biodiversity of megabenthos and coral reef condition in Tuan Island, Aceh Besar

The existence of megabenthos has an important role in maintaining sustainability of coral reef ecosystems and in the food web process. Megabenthos is also often used as an indicator of the health condition of coral reefs. The purpose of study was to analyze the biodiversity of megabenthos associated with coral reef in Tuan Island. This research was conducted in July -September, 2020. There were four research stations determined by purposes method based on four wind directions. Megabenthos data collection carried out by benthos belt transect method and coral reef data collected by using the Line Intercept Transect (LIT) method. The results were found 8 species of megabenthos target, namely spiny starfish (Acanthaster planci), blue starfish (Linckia laevigata), sea urchins (Diadema setosum), sea cucumbers (Holothuria atra), clams (Tridacna squamosa), Drupella snails (Drupella sp.), lola clams (Tronchus niloticus) and lobster (Panulirus versicolor). Totally, there were 190 individuals of megabenthos with the abundance ranged from 0.18 to 0.52 individuals/m2. Diadema setosum had the highest abundance with the value 0.9 individuals/m2 followed by Drupulella sp. (0.3 individuals/m2). The highest diversity index was station 4 followed by station 3, 2, and 1 with the value of 2.21, 0.85, 0.64, and 0.41, respectively. The diversity index was categorized as low and medium. The average of evenness and dominance indices were 0.04 and 0.62, both was medium category. The highest percentage of coral cover was at station 1 followed by station 3, 4, and 2, the coral cover value were 50.44%, 29.20%, 18.14%, and 9.29%, respectively. The correlation (r) between the percentage of coral reef cover and megabenthos abundance has a positive correlation, but the level of correlation was low (0.215 %). The density of megabenthos on Tuan Island did not have a major influence on coral reef cover where the determination value (R2) was 0.0462 which indicated that the megabenthos abundance was influenced by the percentage of coral reef cover only 4.62%.

Pioneer assessment on megabenthic community suggest the recent ecological condition of coral reef in Senggigi Beach, Western Lombok Island, Indonesia

Abstract. Ghafari MIA, Fitrianti V. 2021. Pioneer assessment on megabenthic community suggests the recent ecological condition of coral reef in Senggigi Beach, Western Lombok Island, Indonesia. Indo Pac J Ocean Life 5: 14-21. Megabenthic communities are among the excellent bioindicator used nowadays. This study was the first to conduct in Senggigi Beach and provide preliminary useful information regarding the condition of coral reef ecosystem on-site, through assessing the megabenthic community from 2019-2020 to 202-2021. Benthos Belt Transect (BBT) method was used to collect data from 6 different observation sites. There are 3 groups of targeted megabenthic fauna assessed: the bioindicator group (sea urchin and blue starfish), the corallivorous group (drupella snail and crown-of-thorns starfish), and the commercially valued group (edible sea cucumber, giant clam, spiny lobster, and commercial top shells). Sea urchin was found to dominate all stations, indicating a decreasing live coral cover after bleaching. Presence of corallivorous megabenthos was very rare, as it is not a potential threat to corals. There is a trend of increasing density of edible sea cucumber and giant clam by 30% and 50% respectively, with a mass giant clam recruit in 2021. We suspect less or no impact of anthropogenic activity to megabenthic community dynamic in Senggigi Beach to date, but their community dynamic is purely influenced by the decline condition of coral reef ecosystem due to recent 2016 mass bleaching.

The condition of the coral reef ecosystem in Natuna Island

Three groups of marine biotas in the coral reef ecosystem were analyzed to determine the overall condition coral reef ecosystem in Natuna Island (coral, reef fish, and megabenthos). Nineteen sampling sites are distributed completely in Natuna Island, including Natuna Besar Island, Tiga Island, and Sedanau Island. The coral reef monitoring refers to the Underwater Photo Transect (UPT), and data processing used the Coral Point Count for excel (CPCe). The reef fish observation using the Underwater Visual Census (UVC) and megabenthos observations using the Benthos Belt Transect (BBT). The percentage of the benthic cover was analyzed for several benthic categories. The analysis for reef fish consisted of diversity and abundance for the three fish groups, including the corallivore, herbivore, and carnivore. The megabenthos community’s analysis consisted of diversity and density from eight groups, including giant clams, lobster, Drupella sp., Linckia laevigata, sea urchin, sea cucumber, trochus, and Acanthaster planci. The Coral Reef Health Index (CRHI) analysis was used to determines the coral reef condition in Natuna. Nine sites were categorized as the fair condition of live coral cover with 26.53–36.87%. The largest composition of coral reef fish groups from herbivorous groups and the highest density megabenthos was sea urchins.

KEANEKARAGAMAN BINTANG LAUT (Asteroidea) DI PANTAI LAMALAKA KECAMATAN ILE BOLENG KABUPATEN FLORES TIMUR

Sea star is an invertebrate animal that is included in the phylum Echinoderms from the Asteroidea class. Radial symmetry is shaped and generally has five or more arms and does not have a frame that helps movement. This study aims to determine the diversity of sea star (Asteroidea) in Lamalaka Beach, Ile Boleng District, East Flores Regency.This research will be conducted in July-August 2019, the location of the study is on the Lamalaka coast, Ile Boleng District, East Flores Regency.The method used is a survey method, based on the presence of Asteroidea species that are considered to represent the area. The steps in data collection are field survey, observation, identifying species in each plot, observing and recording their marphological characteristics.Sampling uses the technique of determining the location of sampling using Area sampling. To identify based on Human and Deloach identification guidelines, 2010. Analysis of the data used in this research is quantitative descriptive and the composition of Asteroidea species can be stated based on visual observations calculating species density, relative density, and dominance index, diversity.Based on the results of the study, found 4 species of Asteroidea, namely Protoreaster nodulosus, Linckia laevigata, Echinaster luzonicus, Astropecten polyacanthus. The highest species density calculation results were found in P. nodulosus species with a value of 0.78 ind / m2. while the lowest species density was found in L.laevigata species with a value of 0.63 ind / m2. The highest relative density was found in P. nodulosus species with a value of 27.64%, and the lowest relative density found in L.laevigata species with a value of 22.35 %. The index of starfish species dominance in Lamalaka Beach, obtained a value of D <0.5, indicates that there are no species that dominate in Lamalaka Beach. The existence of starfish in Lamalaka Beach, Ile Boleng District, East Flores Regency needs to be preserved. One form of effort to preserve it is to conduct monitoring with routine monitoring to monitor the condition of the sea star population in these waters. Besides that, it is also necessary to increase the utilization of sea stars as one of the natural tourism objects and as an Ecoedutourism tourism object. Thus, the presence of starfish will be felt by the wider community so that awareness to maintain the existence of starfish will be increased.

Diversity of Echinoderms in Intertidal and Shallow-water Areas of Samal Island, Philippines

Echinoderms are immediately observable around the coastal shores of Samal Island. Unfortunately, studies on echinoderm diversity are lacking despite its relevance to coastal and marine ecosystems management. This study attempts to update the existing records of echinoderms in Samal Island, however, limited to the intertidal and shallow-water areas. Field surveys from January 2018 to January 2019 yielded a total of 30 echinoderm species belonging to 17 families. Most of the echinoderms encountered belonged to Classes Asteroidea (sea stars, nine species) and Ophiuroidea (brittle stars, nine species), followed by Echinoidea (regular and irregular urchins, six species) and Holothuroidea (sea cucumbers, six species). Of the 1,015 individuals, sea urchins comprised the majority of the total individuals recorded (43.15%), succeeded by sea stars (30.44%), brittle stars (18.04%), and sea cucumbers (8.37%). Richest diversity was observed in Catagman with 23 echinoderm species recorded. This was followed by Camudmud (14 species), Pangubatan (eight species), Balet (seven species), Aundanao (six species), and Kaputian (three species). The five most commonly occurring species were the Echinometra mathaei (Blainville, 1825), Archaster typicus (Müller and Troschel, 1840), Ophiocoma scolopendrina (Lamarck, 1816), Diadema setosum (Leske, 1778), and Linckia laevigata (Linnaeus, 1758). Differences in distribution and abundance may be attributed to the variability of habitats available across sites. An intensive biodiversity assessment is recommended to evaluate how the physicochemical parameters and extent of anthropogenic activities shape the diversity and distribution of echinoderms on the island. The current work also provides the first documentation of ophiuroid diversity and the first record of the brittle stars, Breviturma krohi (Stöhr, Boissin & Hoareau, 2013) and Ophiocoma cf. cynthiae (BenavidesSerrato and O’Hara, 2008) in Samal Island, Philippines.

Trophic interactions between gall-forming molluscs <i>Stilifer </i>spp. (Gastropoda, Eulimidae) and their hosts (Echinodermata)

The trophic relationships between two species of symbiotic gall-forming molluscs from the genus Stilifer (family Eulimidae) and two of their hosts-asteroid species, Linckia laevigata and Culcita noveaguineae, were investigated using the stable isotope analysis of carbon and nitrogen. The aim of present study was to identify the most preferable host tissue in the symbionts’ diet. We analyzed δ15N and δ13C values in tube-feet, gonads and digestive glands of the hosts-starfishes and in muscles of the molluscs. Both symbiont species did not differ to each other both in δ15N and δ13C values. The average δ15N and δ13C values of Stilifer variabilis were significantly different from the digestive glands and gonads of their host Culcita novaeguineae and did not show differences from the tube-feet of starfishes. A similar pattern was found in the symbiotic association of Stilifer utinomi and Linckia laevigata. The tube-feet of analyzed starfishes had significantly higher average δ15N and δ13C values than the digestive glands and gonads. Obtained isotopic signatures indicate that symbionts do not feed on the host's tissues, but take nutrients from their digestive system. It seems that the proboscis of Stilifer spp. absorbs the nutrients from the digestive system of the host-starfish thereby not disturbing significantly the host's immune system.

An Investigation into the Genetic History of Japanese Populations of Three Starfish, Acanthaster planci, Linckia laevigata, and Asterias amurensis, Based on Complete Mitochondrial DNA Sequences.

Crown-of-thorns starfish, Acanthaster planci (COTS), are common in coral reefs of Indo-Pacific Ocean. Since they are highly fecund predators of corals, periodic outbreaks of COTS cause substantial loss of healthy coral reefs. Using complete mitochondrial DNA sequences, we here examined how COTS outbreaks in the Ryukyu Archipelago, Japan are reflected by the profile of their population genetics. Population genetics of the blue starfish, Linckia laevigata, which lives in the Ryukyu Archipelago, but not break out and the northern Pacific sea star, Asterias amurensis, which lives in colder seawater around the main Islands of Japan, were also examined as controls. Our results showed that As. amurensis has at least two local populations that diverged approximately 4.7 million years ago (MYA), and no genetic exchanges have occurred between the populations since then. Linckia laevigata shows two major populations in the Ryukyu Archipelago that likely diverged ∼6.8 MYA. The two populations, each comprised of individuals collected from coast of the Okinawa Island and those from the Ishigaki Island, suggest the presence of two cryptic species in the Ryukyu Archipelago. On the other hand, population genetics of COTS showed a profile quite different from those of Asterias and Linckia. At least five lineages of COTS have arisen since their divergence ∼0.7 MYA, and each of the lineages is present at the Okinawa Island, Miyako Island, and Ishigaki Island. These results suggest that COTS have experienced repeated genetic bottlenecks that may be associated with or caused by repeated outbreaks.

Complete mitochondrial genome of a sea star, Linckia laevigata (Echinodermata, Asteroidea, Valvatida, Ophidiasteridae)

We determined the complete mitochondrial genome sequences of an asteroid Linckia laevigata belonging to the order Valvatida. The complete mitogenome of L. laevigata was 16,371 bp in length and consisted of 13 protein-coding genes (PCGs), two rRNA, and 22 tRNA. The orders of PCGs and rRNAs were identical to those of the recorded mitogenomes of asteroids. Phylogenetic analyses placed L. laevigata as the sister group to the species of the other Paxillosida.