Echinoids were collected at depths of 5-10 m in Munseom, Jeju Island by SCUBA diving on November 23, 2008 and September 15, 2009. Two specimens were identified as Echinometra mathaei (Blainville, 1825) based on morphological characteristics and molecular analyses of mitochondrial cytochrome c oxidase subunit I partial sequences. Echinometra mathaei collected from Korea was redescribed with photographs and was compared with other species from GenBank based on molecular data. Phylogenetic analyses showed that no significant differences were between base sequences of E. mathaei from Korea and that from GenBank. To date, 13 echinoids including this species have been reported from Jeju Island, and 32 echinoids have been recorded in Korea.
Genus
Echinoid specimens were collected at depths of 5-10 m in Munseom, Jeju Island by SCUBA diving on November 23, 2008 and September 15, 2009. The specimens were preserved in 95% ethanol, and their important morphological characters were photographed with a digital camera (Canon G12; Canon Co., Tokyo, Japan) and stereo and light microscopy (Nikon SMZ1000, Nikon Eclipse 80
Genomic DNA was extracted from the tubefeet of Korean echinoids using the DNeasy Blood and Tissue kit (Qiagen, Hilden, Germany) for the molecular analysis. The mitochondrial cytochrome
List of taxa and GenBank accession numbers of mitochondrial cytochrome c oxidase subunit 1 (COI) sequences examined in this study
was amplified using ECO1a and ECO1b, as suggested by Knott and Wray (2000). The COI gene fragment corresponding to the interval between sites 5921 to 6861 of the
PCR analyses were conducted according to Lee and Shin (2011). DNA fragments were sequenced on an ABI 3730XL Sequencer (Applied Biosystems Inc., Foster City, CA, USA) using the ABI Prism Bigdye Terminator v3.1 (Applied Biosystems). The mitochondrial COI gene was sequenced, and the sequence data of five species that were not distributed in Korea were obtained from GenBank (Table 1). COI sequences were aligned using CLUSTAL X (Thompson et al., 1997), and genetic distances were calculated according to the Kimura 2-parameter model using MEGA5 (Tamura et al., 2011). The best-fit evolutionary model was identified using the Akaike Information Criterion (AIC) in jMODELTEST (Posada, 2008), and the result was GTR+G(α=0.238). A phylogenetic tree was drawn with neighbor joining (NJ), maximum likelihood (ML), and Bayesian inference (BI) methods. The NJ tree was inferred from the Kimura 2-parameter genetic distance and bootstrapped 1,000 times using MEGA5. The ML tree was analyzed with PHYML v.3.0 (Guindon and Gascuel, 2003) and 1,000 bootstrap replications. The BI analysis was conducted with the same model and analyzed by MrBayes 3.1.2 with 2×106 trees, sampling every 1,000th tree, and credibility values of the nodes were calculated with the 50% majority rule tree after discarding the first 500 trees (Ronquist and Huelsenbeck, 2003).
Class Echinoidea Leske, 1778
Order Camarodonta Jackson, 1912
Infraorder Echinidea Kroh and Smith, 2010
Family Echinometridae Gray, 1855
Key to the genera of family Echinometridae in Korea
1. Test oval shaped, with usually four pore-pairs to an arc ????????????????????????????????????????????????????????????????
Test nearly circular shaped, with usually eight pore-pairs to an arc ???????????????????????????????????????????????????
1*Genus Echinometra Gray, 1825
Test more or less oval shaped, stout, longitudinal axis through interambulacral III to ambulacral 1. Ambulacrals with four pore-pairs per an arc. Apical system with all exserted ocular plates. Primary spines rather long, strong, pointed, Globiferous pedicellariae with one lateral tooth, tubefeet with C-shaped spicules.
Type species:
2*Echinometra mathaei (Blainville, 1825) (Fig. 1)
Material examined. 1 specimen, Munseom, Jeju Island, 23 Nov 2008, at 5 m depth by SCUBA diving; 1 specimen, 15 May 2009, at 10 m depth by SCUBA diving.
Description. Test of small size, strong, hemispherical, oval shaped; ventral side flat, scarcely sunken towards peristome. Ambulacral with four pore-pairs, rarely five to one oblique and rather irregularly curved pore-arcs (Fig. 1E). One of tubercles in pore-zone enlarged and forms a fairly conspicuous vertical. In interambulacral, larger secondary tubercles usually form a distinct vertical series admedially and adradially to primary series. These secondaries vary in size, from almost as large as smaller than primaries. Apical system with all ocular plates exserted (Fig. 1D). Genital plates covered with some small spines, and genital pores developed (Fig. 1D).
Interspecific pairwise distance values (p) between six species of genus Echinometra and outgroups of Heliocidaris crassispina, Mesocentrotus nudus, and Strongylocentrotus purpuratus based on partial sequences of the mitochondrial cytochrome c oxidase subunit 1 (COI) gene
Suranal plate indistinct, and anal opening acentric. Primary spines rather long, about as long as half test diameter, usually rather stout, tapering, and colors getting lighter at tips (Fig. 1F). Secondary spines rather short, with flat tips, looks like rolling pins (Fig. 1F). Globiferous pedicellariae very scarce: valve with a lateral tooth as long as two-thirds of apical tooth (Fig. 1H). Tridentate pedicellariae large: valve with curved tips (Fig. 1I). Ophiocephalous pedicellariae narrow in middle: valve with zigzag edges (Fig. 1J). Triphyllous pedicellariae small: valve width moderately as wide as basal part (Fig. 1K). Tubefeet with C-shaped spicules (Fig. 1L). Buccal plates with some small spines in peristome among a few assemblages of ophiocephalous pedicellariae.
Size. Test diameter, 19.0, 29.0 mm; test height, 9.0, 13.0mm (44.8, 47.4% of test diameter); apical system, 3.8, 6.1 mm (18.0, 19.0% of test diameter); peristome, 9.8, 15.0mm(51.6, 51.7% of test diameter); number of interambulacral plates, 9, 13; number of ambulacral plates, 11, 26.
Distribution. Korea (Jeju Island), Japan (Okinawa), China, Philippines, Hawaii, Solomon Islands, northern Australia, Indo-West Pacific, East Africa (Kenya, Mauritius, Mozam-
bique, Tanzania), Red Sea.
The sequences of our Korean
Genetic pairwise distance (p) values were estimated by the Kimura 2-parameter model and were compared (Table 2). As a result, no differences were found between the two Korean specimens. The average value of Korean
Phylogenetic trees were estimated by BI, NJ and ML methods. Each species of
Korean name: 1*만두성게속(신칭), 2*만두성게(신칭)
Our specimens were identified as
The results of the phylogenetic tree (Fig. 2) indicated that the Korean