Gigantione ishigakiensis Shiino, 1941

An, Jianmei, Yu, Haiyan & Markham, John C., 2009, First record of the genus Gigantione (Epicaridea: Bopyridae: Pseudioninae) from Chinese waters, with description of three new species, Journal of Natural History 43 (5 - 6), pp. 335-353 : 336-341

publication ID	https://doi.org/ 10.1080/00222930802590737
persistent identifier	https://treatment.plazi.org/id/03D9CC30-FFD9-BE05-FE1C-C50C35794367
treatment provided by	Felipe
scientific name	Gigantione ishigakiensis Shiino, 1941
status

Treatment

Gigantione ishigakiensis Shiino, 1941 View in CoL

( Figures 1–3 View Figure 1 View Figure 2 View Figure 3 )

Gigantione ishigakiensis Shiino, 1941, p. 156 View in CoL –158; figures 3, 4. [type locality Ishigakishima, Japan; infesting Carpilius convexus (Forskål) View in CoL ] ( Shiino 1958, p. 48; Danforth 1967, p. 151; Bourdon 1969, p. 952; Shiino 1972, p. 7; Markham 1994, p. 233; Saito et al. 2000, p. 36).

Material examined

Infesting Liagore rubromaculata (De Haan) . Determination of host, Zhengang Fan. Reference female: South China Sea , Stn 6045, 21 ° 45 9 N, 114 ° 30 9 E, 64.5 m, 9 April 1959, Coll. Guangzong Wu, 1♀, CIEX604503 GoogleMaps . Reference male: South China Sea , Stn 6045, 21 ° 45 9 N, 114 ° 30 9 E, 64.5 m, 9 April 1959, Coll. Guangzong Wu, 1 „, CIEX604504 . South China Sea, Stn 6090, 21 ° 00 9 N, 112 ° 30 9 E, 53 m, 22 October 1959, Coll. Yongliang Wang, 1♀, EX 609003, 1 „, EX 609004 GoogleMaps . South Sea, Stn 6090, 21 ° 00 9 N, 112 ° 30 9 E, 53 m, 22 October 1959, Coll. Yongliang Wang, 1♀, CIEX609003 , 1 GoogleMaps „, CIEX609004 . South China Sea, Stn 6045, 21 ° 45 9 N, 114 ° 30 9 E, 64.5 m, 9 April 1959, Coll. Guangzong Wu, 1♀, CIEX604507 , 1 „, CIEX604508 GoogleMaps . Naozhou Island , Guangdong Province, 21 ° 18 9 N, 110 ° 20 9 E, 28 July 1976, Coll. Xianqiu Ren, 1♀, CIEX760701 , 1 GoogleMaps „, CIEX760702 . South China Sea, Stn 6106, 20 ° 30 9 N, 112 ° 00 9 E, 65 m, 29 October 1959, Coll. Yongliang Wang, 1 ♀, CIEX610601 , 1 „, CIEX610602 GoogleMaps . Shanwei , Guangdong Province, 22 ° 47 9 N, 115 ° 21 9 E, 15 January 1955, Coll. Ruiyu Liu (J.Y. Liu), 1♀, CIEX550101 , 1 GoogleMaps „, CIEX550102 . South China Sea, Stn 6118, 20 ° 30 9 N, 111 ° 30 9 E, 61 m, 16 July 1959, Coll. Zhican Tang, 2♀, CIEX611803 , 1 „, CIEX611804 GoogleMaps . South Sea, Stn 6105, 21 ° 00 9 N, 112 ° 00 9 E, 45 m, 4 April 1960, Coll. Zhican Tang, 1♀, CIEX610503 , 1 GoogleMaps „, CIEX610504 . South China Sea, Stn 6118, 20 ° 30 9 N, 111 ° 30 9 E, 61 m, 16 July 1959, Coll. Zhican Tang, 1♀, CIEX611803 , 1 „, CIEX611804 GoogleMaps . South China Sea, Stn 6046, 21 ° 30 9 N, 114 ° 30 9 E, 68 m, 11 July 1959, Coll. Weiquan Zhang, 1♀, CIEX604601 , 1 GoogleMaps „, CIEX604602 . South China Sea, Stn 6106, 20 ° 30 9 N, 112 ° 00 9 E, 65 m, 29 October 1959, Coll. Yongliang Wang, 1♀, CIEX610605 , 1 „, CIEX610606 GoogleMaps . South Sea, Stn 6045, 21 ° 45 9 N, 114 ° 30 9 E, 64.5 m, 9 April 1959, Coll. Guangzong Wu, 1♀, CIEX604509 , 1 GoogleMaps „, CIEX604510 . South China Sea, Stn 6046, 21 ° 30 9 N, 114 ° 30 9 E, 68 m, 11 July 1959, Coll. Weiquan Zhang, 1♀, CIEX604603 , 1 „, CIEX604604 GoogleMaps .

Description of reference female ( CIEX 604503)

Length 9.72 mm, maximal width 9.58 mm across fourth pereomere, head length 2.03 mm, head width 2.73 mm, pleon length 3.27 mm, distortion 6 °. All body regions and segments distinct. No pigmentation ( Figure 1A,B View Figure 1 ).

Head wider than long, without frontal lamina, laterally expanded into lobes. Eyes absent ( Figure 1A View Figure 1 ). Antennae of two and seven articles, respectively ( Figure 1C View Figure 1 ), basal articles greatly expanded. Barbula ( Figure 1D View Figure 1 ) with one large falcate projection on each side, many pairs of small projections near middle region, and pair of large triangular projections medially. Maxilliped ( Figure 1E View Figure 1 ) nearly rectangular, fringed with long plumose setae, lacking palp, its anterior article much larger than posterior one.

Pereomeres distinct, fourth one broadest. All pereomeres with conspicuous coxal plates, those on long side longer than those on short side. Dorsolateral bosses on both sides of first four pereomeres. Brood pouch incompletely covered by oostegites. First oostegite ( Figure 1F,G View Figure 1 ) with anterior article much larger but narrower than posterior one, lateral margin of anterior article fringed with setae, internal ridge bearing five to seven projections on lateral half, posterolateral point obscure. Pereopods of about same size, their bases non-carinate ( Figure 1H View Figure 1 ).

Pleon of six pleomeres, first five produced into pointed lateral plates on both sides. All pleopods biramous, visible only ventrally. First pleopod ( Figure 1I View Figure 1 ) lamellar, much larger than other pleopods, other four pairs nearly trifurcate, exopodites ramified into inner and outer lobes, with deeply digitate margins ( Figure 1J,K View Figure 1 ). Biramous uropoda of two slender rod-shaped branches.

Description of reference male ( CIEX 604504)

Length 4.15 mm, maximal width (across fifth pleomere) 1.25 mm, head length 0.49 mm, head width 0.82 mm, pleonal length 1.45 mm. All body segments distinct, no pigment ( Figures 2A View Figure 2 , 3A View Figure 3 ).

Head semicircular, bearing small eyes near posterior edge ( Figure 2A View Figure 2 ). Antennae of three and six articles respectively. Second antenna much longer than first antenna, visible in dorsal view ( Figure 3A,B View Figure 3 ).

Third to sixth pereomeres almost equally wide, their margins truncate. Midventral projections absent ( Figures 2B View Figure 2 , 3A View Figure 3 ). First pereopod slightly larger than other six pereopods, dactyli and propodi much larger than those of other pereopods ( Figure 3A–C View Figure 3 ).

Pleon of six pleomeres, without midventral projections first four pairs of pleopods club-like, fifth pleopods coniform, ( Figure 3A,D View Figure 3 ); sixth pleomere produced into symmetrical columniform uropods ( Figure 3E View Figure 3 ), their posterior margins concave medially and setose ( Figure 3F View Figure 3 ).

Description of immature specimens (female: CIEX 611803; male: CIEX 611804)

Female length 6.89 mm, maximal width across pereomere 4, head width 2.42 mm, head length 1.98 mm, pleon length 1.96 mm. Head triangular, laterally expanded into prominent lobes, with small eyes ( Figure 2D View Figure 2 ). Segments distinct, all pereomeres with conspicuous coxal plates and all pleomeres with prominent lateral plates. Brood pouch open, and oostegites rectangular ( Figure 2E View Figure 2 ). One cryptoniscus larva ( Figure 2F View Figure 2 ) attached to pleon of immature female, and length 3.14 mm, head width 0.78 mm, pleon length 1.34 mm.

Remarks

This is only the second record of this species, which was heretofore known only from the type locality in Japan. Shiino (1941) based his description of G. ishigakiensis on the single type pair but not including some important characters. Bourdon (1969) and Markham (1994) noted that G. ishigakiensis Shiino and G. moebii Kossmann , as described by Kossmann (1881) and redescribed by Bonnier (1900) and Bourdon (1969), may be synonyms. The female G. moebii have more extended heads and uropods, a more elaborate internal ridge on the first oostegite and digitate margins on the pleonal lateral plates. The present specimens ( Figure 1 View Figure 1 ) conform well to the description by Shiino (1941). As Shiino (1941) stated, the second to fifth pleopods of females are nearly trifurcate and the exopodites are ramified into inner and outer lobes. However, there are some minor differences: our females lack frontal laminae, their antennae are not visible in dorsal view, the middle region of each barbula has a pair of blunt projections and the maxillipeds have no projections on the palp region.

Another male ( CIEX 604508) ( Figure 2C View Figure 2 ) differs from the reference male in that the posterior margins of its uropods are not concave but are medially convex.

Many host specimens have both branchial chambers infested, one chamber occupied by G. ishigakiensis , while the other contains Dactylokepon barbuladigitus An et al. 2007 . An et al. (2007) commented that although many bopyrids infested both branchial chambers of their hosts, it is rare that two different species were found in the two chambers of one and the same host.

Distribution and hosts

Ishigakishima, Japan; infesting Carpilius convexus (Forskål) ; South China Sea, Guangdong Province, China, infesting Liagore rubromaculata (De Haan) .