Chrysaora pacifica ( Goette, 1886 )

Morandini, André C. & Marques, Antonio C., 2010, Revision of the genus Chrysaora Péron & Lesueur, 1810 (Cnidaria: Scyphozoa) 2464, Zootaxa 2464, pp. 1-97 : 40-45

Chrysaora pacifica ( Goette, 1886)

( Figures 50 –56, 80, 92)

Dactylometra quinquecirrha var. pacifica Goette 1886: 834–835 (description) [Nagasaki – Japan]. Stiasny 1919: 81 (commented that D. quinquecirrha pacifica is probably D. quinquecirrha ). Stiasny 1939: 183 (commented that D. quinquecirrha pacifica , D. ferruginaster , and D. longicirrha probably form a sequence of developmental stages) [non Chrysaora quinquecirrha ( Desor, 1848) ].

Dactylometra pacifica: Vanhöffen 1888: 49 (distribution). Bigelow 1913: 91 (mention), 92 (description) [Tsuruga Gulf – Japan]. Uchida 1927: 229–230 (historical comments). Uchida 1935: 44 (brief description). Koizumi & Hosoi 1936: 712 (inorganic composition), 713–719 (tables) [ Japan]. Uchida 1938a: 148 (mention) [Honshu – Japan]. Uchida 1938b: 44 (mention) [ Japan]. Uchida 1938c: 57 (mention) [Konorihama – Japan]. Uchida 1940: 278 (list), 279, 281 (occurrence), 294 (brief description) [ Japan]. Komai 1942: 26–28 (ephyrae nervous system), fig. 2 (mouth aperture), fig. 3 (nervous cell), fig. 4 (sense organ) [ Japan]. Uchida 1947: 342 (mention) [Shimoda – Japan]. Chiu 1954: 56 (mention). Uchida 1954: 210, 213, 214, 215, 216 (mention) [ Japan]. Uchida 1955: 15 (brief description). Yamazi 1958: 139 (mention) [Tanabe Bay – Japan]. Uchida Yamada, Iwata, Oguro & Nagao 1963: 16 (mention) [ Japan]. Thiel 1966: 21 (mention). Kakinuma 1967: 29–33 (life cycle), fig. 1, Pl. I figs 2–6, Pl. II figs 7–8 (polyp), fig. 2, Pl. II figs 11–12, Pl. III fig. 2 (ephyra), Pl. I fig. 1 (planula), Pl. II figs 9–10, Pl. III fig. 1 (strobilation) [ Japan]. Uchida 1970: 299 (list), 300 (occurrence) [ Japan].

Dactylometra longicirra Kishinouye 1892: 262–263 (original description), Pl. II (medusa) [Owari Bay – Japan]. Mayer 1910: 589 (description, = D. ferruginaster = Kuragea depressa ).

Dactylometra ferruginaster Kishinouye 1892: 264 (original description), Pl. III (medusa) [ Japan]. Mayer 1910: 588–589 (description). Bigelow 1913: 91 (mention). Stiasny 1919: 81 (commented that D. ferruginaster probably D. quinquecirrha ). Stiasny 1939: 183 (commented that D. quinquecirrha pacifica , D. ferruginaster , and D. longicirrha probably form a sequence of developmental stages) [non Chrysaora quinquecirrha ( Desor, 1848) ]. Cleland & Southcott 1965: 148 (mention).

Kuragea depressa Kishinouye 1902: 9–10 (original description), Pl. I fig. 7 (medusa) [Misaki – Japan]. Mayer 1910: 589–590 (description), fig. 374 (medusa). Bigelow 1913: 91 (mention). Stiasny 1922: 519–521 (description, commented that D ferruginaster is identical to D. pacifica ferruginaster and to D. quinquecirrha pacifica ), fig. 2 (medusa) [Misaki – Japan] [non Chrysaora quinquecirrha ( Desor, 1848) ]. Uchida 1927: 230 (different from D. pacifica ). Uchida 1935: 44–45 (brief description; specimens of Stiasny 1922 = D. pacifica ). Uchida 1954: 210, 214, 215 (mention) [ Japan]. Thiel 1966: 20, 21 (mention).

Chrysaora convoluta Kishinouye 1910: 11–13 (original description), Pl. II figs 11–14 [Okhotsk Sea – Russia]. Stiasny 1919: 74 ( C. convoluta = C. melanaster ) [Yokohama – Japan].

Dactylometra pacifica ferruginaster: Maas 1910: 4 (list), 43 (mention), 44 (brief description), Pl. II fig. 14 [ Japan].

Dactylometra longicirrha: Bigelow 1913: 91 (mention). Stiasny 1919: 81 (commented that D. longicirrha probably D. quinquecirrha ). Stiasny 1939: 183 (commented that D. quinquecirrha pacifica , D. ferruginaster , and D. longicirrha probably form a sequence of developmental stages) [non Chrysaora quinquecirrha ( Desor, 1848) ].

Chrysaora depressa: Kramp 1961: 324 (synonymy). Gershwin & Collins 2002: 128 (mentioned as nominal species with insufficient data).

Chrysaora pacifica: Kramp 1961: 327 (synonymy, considered as an unrecognizable species). Gershwin & Collins 2002: 128 (mention), 129 (tab. 1), 130 (mention), 133 (mention), fig. 2 (phylogeny).

Chrysaora melanaster: Calder 1972: 41 (mention = D. pacifica ). Arai 1997: 14 (cuticle), 134 (water content), 136, 175 (composition), 153, 155 (larval development), 166 (strobilation). Collins 2002: 420 (tab. 1). Morandini, Silveira & Jarms 2004: 347, 348, 352, 353 (mention). Kawahara, Uye, Ohtsu & Iizumi 2006: 172 (mention) [ Japan]. Kinoshita, Hiromi & Yamada 2006: 607, 611 (abundance, biomass) [ Japan]. Widmer 2008b: 81 (key). Arai 2009: 243 (podocysts). Bayha & Graham 2009: 221 (molecular identification polyps). Ki, Kim & Lee 2009: 230, 232, (mention). [non Chrysaora melanaster Brandt, 1835 ].

Type series. Holotype specimen: ZMB CNI 2602 (as Chrysaora quinquecirrha var. pacifica , ~ 7 cm in diameter, 6.vi.1884, ethanol, Nagasaki – Japan); Paratype specimens: ZMB CNI 2600 (as Chrysaora quinquecirrha pacifica , ~ 8 cm in diameter, ethanol, Japan), ZMB CNI 2601 (as Chrysaora quinquecirrha var. pacifica , ~ 8 cm in diameter, ethanol, Japan).

Examined material. Holotype; paratypes; MZUSP 796 (as Chrysaora melanaster , ~ 0.5 cm in diameter, 21.vi.2004, from laboratory cultures, 4% formaldehyde solution in seawater), MZUSP 806 (as Chrysaora melanaster , specimens ~2.5 and 6 cm in diameter, 07.vi.2004, from laboratory cultures, 4% formaldehyde solution in seawater), MZUSP 808 (as Chrysaora melanaster , specimens ~ 2–4 cm in diameter, 06.vii.2004, from laboratory cultures, 4% formaldehyde solution in seawater); NNM 5281 (as Chrysaora melanaster , specimens ~6 and 6 cm in diameter, 4.v.1917, Yokohama – Japan); USNM 29945 (as Chrysaora melanaster , specimens 5 and 7.5 cm in diameter, 23.vii.1906, Tsuruga Bay – Japan); USNM 29946 (as Chrysaora melanaster , specimens 8 and 9 cm in diameter, 10.x.1906, Kinkazan island – Japan); USNM 29950 (as Chrysaora melanaster , specimens 10 and 10 cm in diameter, 15.v.1900, Ise Bay – Japan); USNM 29988 (as Chrysaora melanaster , specimen 13 cm in diameter, 15.v.1900, Ise Bay – Japan); ZMB CNI 14802 (as Dactylometra ferruginaster , ~ 3.5 cm in diameter, Kobe – Japan); ZMUC not-numbered (as Kuragea depressa , ~3.5 and 5 cm in diameter, 26.iv.1914, Misaki – Japan,), ZMUC not-numbered (as Kuragea depressa , specimens ~3, 4, 4, 5, 5, and 6 cm in diameter, – only jelly, 25.iv.1914, Misaki – Japan).

Type locality. Nagasaki, Japan.

Distribution. North Pacific Ocean ( Japan) ( Fig. 80).

Diagnosis. Living medusa small, typically 10–15 cm in diameter; marginal lappets (adults) rounded, 4–10 per octant, without canals; 24–72 tentacles (3–9 per octant, 5-4-3-2-1-2-3-4-5); quadralinga absent; colouration (adults) whitish with thin brownish radiating stripes.

Holotype specimen description. Umbrella diameter 7 cm, slightly flattened ( Fig. 50). Exumbrellar surface finely granulated; brownish (maybe due to preservation), but translucent. Mesoglea flexible, relatively thick (~ 1cm) on central portion, thinner at edge. Marginal lappets rounded, 6 per octant (2 rhopalar and 4 tentacular); rhopalar lappets slightly shorter than velar, rhopalar lappets not overlapping (“open rhopalia” condition). Rhopalia 8, without ocelli, in deep clefts; deep exumbrellar sensory pit. Tentacle clefts vary in depth. Tentacles broken off, probably 40 (5 per octant), longer than bell diameter; arranged as primary tentacle central, 2 tertiary tentacles most peripheral, 2 secondary tentacles between primary and tertiary tentacles (3-2-1- 2-3). Musculature not distinguishable. Brachial disc circular, but with four evident corners, grooved. Pillars evident, 1 cm wide, delimited by insertion corners of manubrium. Subgenital ostia pear-shaped, 0.7 cm in diameter. Oral arms ca. 8 cm long, V-shaped, delicate and convoluted edges, distal portion slightly spiraled, distal 1 / 3 with reduced free edge. Central stomach circular, marginal region limited by insertion of radial septa. Stomach pouches 16, width uniform centrally; tentacular pouches enlarged distally. Radial septa thin, with rounded base; straight up to ¼ of margin, then making an “S” (first thinning tentacular pouch, then enlarging it); ending near tentacular base at rhopalar lappet, proximal region of the radial septa hard to see due to enlarged brachial disc. Gastric filaments in four interradial fields. Quadralinga absent. Gonads outlining gastric filaments, semicircular ring, greatly folded; sex undetermined.

Description of other specimens and additional data. Medusa: Umbrella diameter up to 20 cm (3–8 cm in preserved specimens measured), almost hemispherical (Figs 52–53), flattened in younger specimens (0.5–3 cm), varying in preserved specimens. Exumbrellar surface finely granulated; whitish with thin brownish radiating stripes (Figs 52–53). Mesoglea flexible, relatively thick on central portion, thinner at edge. Marginal lappets rounded, 2–6 per octant; rhopalar lappets slightly larger than velar, rhopalar lappets not overlapping (“open rhopalia” condition). Rhopalia 8, without ocelli, in deep clefts; deep exumbrellar sensory pit. Tentacle clefts varying in depth. Tentacles up to 72 (3–9 per octant); arranged primary tentacle central, secondary, tertiary, quaternary, quinary tentacles laterally (5–4-3-2-1-2-3-4-5). Musculature not distinguishable. Brachial disc circular, but with four evident corners, grooved in larger specimens. Pillars evident, delimited by insertion corners of manubrium. Quadralinga absent. Subgenital ostia pear-shaped, ca. 1 / 6 of umbrellar diameter. Oral arms one-two times longer than umbrellar diameter, V-shaped, delicate and convoluted edges, distal portion slightly spiraled. Central stomach circular, marginal region limited by insertion of radial septa. Stomach pouches, 16, width uniform centrally; tentacular pouches enlarged distally. Radial septa thin; rounded at base; straight up to ¼ of margin, then making an “S” (first thinning tentacular pouch, then enlarging it); ending near tentacular base at rhopalar lappet (Figs 51, 54). Gastric filaments in four interradial fields. Gonads outlining gastric filaments, semicircular ring, greatly folded. Planula. Planulae oval to spheroidal; 0.2–0.3 mm long, 0.13–0.15 mm wide; brownish. Scyphistoma (Fig. 55). Conical to goblet-shaped, up to 1 mm high; oral disc 1.8 mm wide; tentacles typically 16 tentacles (16–18), length up to 5–6 times polyp height. Mouth cruciform, with prominent lips elevated from oral disk. Gastric septa 4. Whitish. Podocysts. Trapezoid, diameter 0.3–0.4 mm; yellowish brown. Strobila. Polydisc (1–30 ephyrae), pinkish. Ephyra (Fig. 56): typically with 8 arms (lobes); marginal lappets 16, pointed, slightly curved, with points converging; rhopalia 8; mouth cruciform; diameter 2–3 mm just after liberation; pinkish; with one nematocyst cluster on each side of rhopalium. Cnidome ( Fig. 92): Specimen USNM 29945, medusa tentacles with holotrichous O-isorhizas [n=10; 8.8–9.8 x 6.8–7.8 µm (mean = 9.5 x 7.45 µm)]; holotrichous a-isorhizas [n=10; 5.8–6.8 x 2.9–3.9 µm (mean = 6.27 x 3.72 µm)]; holotrichous A-isorhizas [n=10; 10.7–13.7 x 5.8–6.8 µm (mean = 13.03 x 6.76 µm)]; heterotrichous microbasic rhopaloids [n=10; 9.8–10.7 x 4.9–5.8 µm (mean = 10.29 x 5.78 µm)]; Specimen USNM 29946, medusa tentacles with holotrichous O-isorhizas [n=10; 8.8–9.8 x 6.8–7.8 µm (mean = 9.6 x 7.64 µm)]; holotrichous a-isorhizas [n=10; 4.9 x 2.9–3.9 µm (mean = 4.9 x 3.03 µm)]; holotrichous A-isorhizas [n=10; 11.7–13.7 x 5.8–7.8 µm (mean = 12.94 x 6.86 µm)]; heterotrichous microbasic rhopaloids [n=10; 8.8–9.8 x 5.8 µm (mean = 9.7 x 5.8 µm)].

Systematic remarks. This species has been misidentified several times as Chrysaora melanaster . We distinguish the two species based on differences in the number of tentacles and lappets, and additional detailed developmental and genetic studies may provide support to these differences (e.g. description of the life cycle of C. melanaster ; genetic comparison of animals from wild populations, not from aquarium reared ones). We believe that all medusae displayed in public aquaria as C. melanaster are C. pacifica . Numbers of tentacles can vary greatly in the species (up to 9 tentacles per octant). Chrysaora pacifica occurs in the northern Pacific Ocean, in the vicinity of Japan ( Goette 1886; Uchida 1970). This species does not possess quadralinga, nor canals in the marginal lappets, but it can develop up to five tentacles per octant (eventually seven or up to nine) ( Gershwin & Collins 2002; Morandini, unpublished data). Because other species of Chrysaora occur in northern Japanese waters (see Uchida 1954) and there is a lack of preserved museum specimens for inspection, the correct identification of the species remains uncertain.

Biological data. Life cycle described by Kakinuma (1967).

Etymology. pacifica : derived from the area where the species was discovered ( Japan, Pacific Ocean).