Styela plicata ( Lesueur, 1823 )

Pyo, Jooyeon, Lee, Taekjun & Shin, Sook, 2012, Two newly recorded invasive alien ascidians (Chordata, Tunicata, Ascidiacea) based on morphological and molecular phylogenetic analysis in Korea *, Zootaxa 3368 (1), pp. 211-228 : 222-224

5. Styela plicata ( Lesueur, 1823)

( Figs. 2E , 3A, B , Table 3)

Ascidia plicata Lesueur, 1823: 5 ; De Kay, 1843: 259. Styela pinguis Herdman, 1899: 37 . Styela plicata: Herdman, 1899: 40 ; Van Name, 1945: 295, figs. 192, 194; Tokioka, 1954: 89; 1960: 212; Kott, 1972: 185;

Yamaguchi, 1975: 253; Rho & Lee, 1991: 202; Lambert & Lambert, 1998: 675; Rho et al., 2000: 42; Baker et al., 2004:

74; Da Rocha & Kremer, 2005: 1170; De Barros et al., 2009: 45; Pineda et al., 2011: 1; Sanamyan & Monniot, 2011d:

103936; Fuller, 2012: 1293. Tethyum plicatum: Van Name, 1912: 569 , fig. 136.

Materials examined. 8 inds., Guryoungpo , 12 Aug. 2009, Lee T, thick cloth at 1.4 m depth ; 14 inds., Gampo , 12 Aug. 2009, Shin S, thick cloth at 2.1 m depth ; 7 inds., Jangsaengpo , 13 Aug. 2009, Shin S, ropes at 2.4 m depth ; 16 inds., Daebyeon , 13 Aug. 2009, Shin S, ropes at 3.1 m depth ; 8 inds., Busan, 14 Aug. 2009, Lee T, under floating dock at 0.3 m depth ; 3 inds., Dadaepo , 14 Aug. 2009, Lee T, under floating dock at 0.2 m depth ; 269 inds., Tongyeong , 14 Aug. 2009, Shin S, ropes at 2.5 m depth ; 11 inds., Gwangyang , 16 Aug. 2009, Shin S, fish trap at 3.7 m depth ; 6 inds., Seogwipo , 20 Aug. 2009, Shin S, ropes at 2.5 m depth ; 3 inds., Guryoungpo , 13 Nov. 2009, Lee T, thick cloth at 1 m depth ; 6 inds., Gampo , 13 Nov. 2009, Lee T, under floating dock at 0.2 m depth ; 6 inds., Jangsaengpo , 14 Nov. 2009, Shin S, ropes at 2.5 m depth ; 5 inds., Daebyeon , 14 Nov. 2009, Shin S, ropes at 3.8 m depth ; 10 inds., Busan, 14 Nov. 2009, Shin S ,, ropes at 3.1 m depth ; 9 inds., Dadaepo , 14 Nov. 2009, Lee T, under floating dock at 0.2 m depth ; 290 inds., Tongyeong , 15 Nov. 2009, Shin S, dock wall at 1.7 m depth ; 14 inds., Gwangyang , 15 Nov. 2009, Lee T, fish trap at 3.1 m depth ; 8 inds., Seogwipo , 17 Nov. 2009, Shin S, ropes at 3.1 m depth ; 13 inds., Yangpo , 24 June 2010, Shin S, ropes at 3 m depth ; 16 inds., Bangeojin , 25 June 2010, Shin S, ropes at 2.1 m depth ; 5 inds., Jangsaengpo , 25 June 2010, Lee T, fish trap at 3.7 m depth ; 4 inds., Busan, 25 June 2010, Lee T, under floating dock at 0.1 m depth ; 16 inds., Dadaepo , 26 June 2010, Shin S, ropes at 2.6 m depth ; 327 inds., Tongyeong , 26 June 2010, Shin S, dock wall at 2.8 m depth ; 9 inds., Gwangyang , 27 June 2010, Lee T, fish trap at 3.2 m depth ; 10 inds., Seogwipo , 30 June. 2010, Lee T, ropes at 3.4 m depth ; 31 inds., Yangpo , 19 Oct. 2010, Shin S, ropes at 3.2 m depth ; 19 inds., Gampo , 19 Oct. 2010, Pyo J, ropes at 2.7 m depth ; 4 inds., Jangsaengpo , 20 Oct. 2010, Lee T, dock wall at 2 m depth ; 8 inds., Busan, 20 Oct. 2010, Pyo J, dock wall at 3 m depth ; 24 inds., Dadaepo , 21 Oct. 2010, Shin S, ropes at 2.1 m depth ; 547 inds., Tongyeong , 21 Oct. 2010, Shin S, fish trap at 3.3 m depth ; 11 inds., Gwangyang , 21 Oct. 2010, Lee T, fish trap at 2.5 m depth ; 20 inds., Seogwipo , 17 Oct. 2010, Pyo J, ropes at 2.1 m depth ; 21 inds., Yangpo , 24 June 2011, Shin S, ropes at 3.4 m depth ; 17 inds., Bangeojin , 25 June 2011, Shin S, ropes at 2.2 m depth ; 9 inds., Jangsaengpo , 25 June 2011, Lee T, fish trap at 2.3 m depth ; 5 inds., Busan, 25 June 2011, Pyo J, under floating dock at 0.2 m depth ; 12 inds., Dadaepo , 25 June 2011, Shin S, ropes at 2.6 m depth ; 75 inds., Tongyeong , 26 June 2011, Pyo J, dock wall at 3.8 m depth ; 9 inds., Seogwipo , 17 June 2011, Pyo J, ropes at 3.4 m depth ; 20 inds., Yangpo , 18 Oct. 2011, Shin S, ropes at 2.1 m depth ; 11 inds., Jangsaengpo , 19 Oct. 2011, Lee T, fish trap at 3.1 m depth ; 9 inds., Busan, 19 Oct. 2011, Pyo J, dock wall at 1.6 m depth ; 16 inds., Dadaepo , 19 Oct. 2011, Lee T, under floating dock at 0.2 m depth ; 323 inds., Tongyeong , 20 Oct. 2011, Shin S, ropes at 3.1 m depth ; 6 inds., Gwangyang , 20 Oct. 2011, Pyo J, fish trap at 3.2 m depth ; 13 inds., Seogwipo , 25 Oct. 2011, Pyo J, ropes at 3 m depth .

Distribution. Native to Northeast America, Gulf of Mexico and West Indies. Mediterranean Sea, South Africa, Brazil, Argentina, California, South Australia, Tasmania, China, Japan, and Korea ( Korea Strait, Jeju Island).

Molecular phylogenetic analysis. In the jModeltest procedure, the Akaike Information Criterion (AIC) showed that the GTR+I+G model was the best-fitted model among those evaluated. The parameters of the model were as follows: base frequencies, A = 0.2383, C = 0.2272, G = 0.3050, T = 0.2295; substitution rate matrix, A–C = 0.3903, A–G = 1.4160, A–T = 0.8681, C–G = 0.6066, C–T = 4.0151, G–T = 1.0000; proportion of invariable sites 0.4250; gamma shape parameter 0.4350. We investigated the phylogenetic relationships between five Korean ascidian species and the allied species registered in the GenBank. The analysis of the base sequences of Korean ascidians was carried out using twenty-three samples of nuclear 18S rDNA and ten of mt-COI. Korean ascidians used for the analysis of 18S rDNA sequences were Ascidiella aspersa , Halocynthia roretzi , Molgula manhattensis , Styela clava , and S. plicata , among which A. aspersa , M. manhattensis and S. plicata were also used for mt-COI analysis. These base sequences were employed for the construction of the phylogenetic tree by Bayesian inference method and the trees obtained using each sequence of nuclear 18S rDNA ( Fig. 6 ) and mt-COI ( Fig. 7 ). Korean A. aspersa exactly formed a phylogenetic group with same species referred from GenBank in each phylogenetic tree of nuclear 18S rDNA and mt-COI ( Figs. 6 , 7 ), and made particularly significant distinction from the other species of genus Ascidia of the same family in phylogenetic tree of nuclear 18S rDNA ( Fig. 6 ). Korean M. manhattensis also formed a phylogenetic group with same species from Genbank in both phylogenetic trees of nuclear 18S rDNA and mt-COI. But, M. manhattensis was grouped with M. retortiformis in nuclear 18S rDNA dataset ( Fig. 6 ) and with M. provisionalis in mt-COI dataset ( Fig. 7 ).

Figures

FIGURE 2. Five invasive alien ascidians at four collection sites in Korea: A, C. lepadiformis attached to dock wall at 4.7 m depth in Busan port; B, A. aspersa attached to ropes at Tongyeong yacht marina; C, C. intestinalis attached on thick cloth at Gampo harbor; D, M. manhattensis attached on floating buoy at Mokpo yacht marina; E, S. plicata attached to rope at Tongyeong yacht marina. Scale bars: A–E. 10 cm.

FIGURE 3. Different invasive ascidians attached to same rope at different dates at Tongyeong yacht marina: A, B, S. plicata (Oct. 2010); C, D, A. aspersa (June 2011). The red arrow indicates that an individual of S. plicata was surrounded by several individuals of A. aspersa.

FIGURE 6. Phylogenetic relationship of some ascidians including four invasive alien species inferred from nuclear 18S rDNA dataset. Species, sampling locations in Korea and Genbank accession numbers were given and numbers on branches were Bayesian posterior probabilities (if ≥ 0.80). The tree was rooted with Branchiostoma floridae. The scale bar represents the number of expected changes per site.

FIGURE 7. Phylogenetic relationship of some ascidians including three invasive alien species inferred from mt–COI dataset. Species, sampling locations in Korea and Genbank accession numbers were given and numbers on branches were Bayesian posterior probabilities (if ≥ 0.80). The tree was rooted with Branchiostoma floridae. The scale bar represents the number of expected changes per site.