Chrysaora fuscescens Brandt, 1835

Morandini, André C. & Marques, Antonio C., 2010, Revision of the genus Chrysaora Péron & Lesueur, 1810 (Cnidaria: Scyphozoa) 2464, Zootaxa 2464, pp. 1-97 : 22-26

Chrysaora fuscescens Brandt, 1835

( Figures 24 –28, 76, 88)

Chrysaora fuscescens Brandt 1835: 227 (original description) [Aleutian Islands – USA]. Brandt 1838: 384 (assigned as a synonym of C. helvola ). Haeckel 1880: 515 (assigned as a synonym of C. helvola ). Shenker 1984: 623–630 (occurrence, distribution), fig. 3 (density), fig. 4 (size variation) [Oregon – USA]. Shenker 1985: 169–173 (Carbon content) [Newport, Oregon – USA]. Mills 1987: 67 (mention, key) [northwest Pacific Ocean]. Arai 1988: 1918, 1921 (mention). Larson 1990: 547 (mention), 549 (mention, tab. 1), 552 (commented on the history concerning the name of the species; C. fuscescens is considered identical to C. gilberti , to C. helvola , and to Melanaster mertensii), 552– 553 (occurrence, abundance), fig. 1D (medusa) [from Bering Sea to Mexico]. Larson & Arneson 1990: 131 (Tab. 1) [California – USA]. Cairns et al. 1991: 12 (list), 62 (index). Sommer 1992: 363–364 (cultivation details). Sommer 1993: 250, 253 (cultivation details), 252 (feeding). Lange & Kaiser 1995: 62 (cultivation details). Arai 1997: 134 (water content), 175 (composition), 188 (biomass), 198 (aggregation), 225 (classification). Wrobel & Mills 1998: 18 (photo), 20 (photo), 53 (description), 93, 99, 102, 103 (mention). Gershwin, 1999: 995 (ephyrae variation). Graham, Pagès & Hamner 2001: 204, 205, 206, 208 (mention). Raskoff 2001: 121, 128 (mention). Gershwin & Collins 2002: 128 (mention), 129 (tab. 1), 130 (mention), 131 (mention, absence of quadralinga), 134 (mention), 141 (mention), 142 (key), fig. 2 (phylogeny). Dabiri & Gharib 2003: 3676–3680 (swimming kinematic model), fig. 1 (medusa). Raskoff, Sommer, Hamner & Cross 2003: tab. 1 (cultivation details). Kimball, Arambula, Stauffer, Levy, Davis, Liu, Rehmus, Lotan & Auerbach 2004: 102 (mention), 105–107 (test of efficiency of protecting lotion against stings), tab. 1, fig. 1 (medusa), fig. 4 (tentacle test). Suchmann & Brodeur 2005: 52, 55, 59, 60, 66, 67 (abundance, distribution) [California – USA]. Burnett 2006: 180–186 (sting effect) [San Diego – USA]. Purcell, Uye & Lo 2007: 160– 161 (mention, blooms). Brodeur, Suchman, Reese, Miller & Daly 2008a: 649–659 (interaction fish) [California – USA]. Suchman, Daly, Keister, Peterson & Brodeur 2008: 161–172 (feeding pattern) [California – USA]. Widmer 2008b: 71–82 (life cycle) [Monterey Bay – USA]. Arai 2009: 243 (podocysts). Bayha & Graham 2009: 221 (molecular identification of polyps). Crossley, George & Keller 2009: 174–179 (treatment hyperid infestation) [Oregon – USA]. Dawson & Hamner 2009: 205 (mention). Purcell 2009: 32, 34, 43 (mention, trophic ecology).

Chrysaora (Polybostrycha) helvola Brandt 1838: 384–385 (original description), Pl. XV figs 1–3 (medusa) [Aleutian Islands – USA]. Lesson 1843: 402–403 (description).

Polybostrycha helvola: L. Agassiz 1862: 126 , 166 (mention). A. Agassiz 1865: 50 (brief description). Larson 1990: 552 (= C. fuscescens ).

? Melanaster mertensii L. Agassiz 1862: 126, 166 (mention, n. gen.). A. Agassiz 1865: 50 (brief description). Larson 1990: 552 (= C. fuscescens ).

Chrysaora helvola: Haeckel 1880: 515 (description) [North Pacific Ocean]. Vanhöffen 1888: 23 (brief description), 48 (distribution). Vanhöffen 1906: 48–49 (brief description), fig. 11 (medusa) [Aleutian Islands – USA]. Mayer 1910: 580 (synoptic table), 581–582 (description), fig. 366 (medusa). Stiasny 1919: 74 (expressed doubts if C. helvola is identical to C. melanaster ). Uchida 1935: 43–44 (brief description), fig. 2 (medusa). Uchida 1940: 278 (list), 279 (occurrence), 294 (brief description) [ Japan]. Uchida 1954: 210, 213, 214, 215, 216 (mention) [ Japan]. Naumov, 1956: 38 (mention, tab.). Kramp 1961: 324–325 (synonymy). Uchida, Yamada, Iwata, Oguro & Nagao 1963: 16 (mention). Larson 1990: 552 (= C. fuscescens ). Zavolokin, Glebov & Kosenok 2008: 463, 465 (occurrence, distribution) [Bering Sea].

Chrysaora melanaster: Fewkes 1889: 25–26 (description) [California – USA]. Larson 1990: 549 (mention, tab. 1), 552 (historical), 552 ( C. melanaster of Fewkes, 1889 = C. fuscescens ), fig. 1E (medusa, after Brandt 1838) [Bering Sea] [non Chrysaora melanaster Brandt, 1835 ].

Chrysaora gilberti Kishinouye 1898: 44–45 (original description); unnumbered fig. (medusa) [Monterey Bay, California – USA]. Galigher 1925: 96 (occurrence of ephyrae) [Monterey Bay, California – USA]. Vannucci 1954: 125 (commented that C. gilberti is identical to C. melanaster ). Hartman & Emery 1956: 307 (mention). Larson 1990: 552 (= C. fuscescens ).

Holotype specimen. Not available; but the holotype of the junior synonym Chrysaora gilberti was found at the USNM collection and is now designated as a neotype.

Neotype specimen. USNM 18943 as Chrysaora gilberti (~ 8 cm in diameter, 17.ii.1898, 4% formaldehyde solution, Monterey Bay , California – USA).

Examined material. Neotype; CASIZ 8892 (as Chrysaora sp. , ~ 10 cm in diameter, 22.vii.1912, ethanol 75%, San Francisco Bay, California – USA), CASIZ 95517 (specimens ~4 and 5.5 cm in diameter, no date, ethanol 75%, Monterey Bay, California – USA), CASIZ 95534 (as Chrysaora sp. , ~ 6.5 cm in diameter, 31.v.1931, ethanol 75%, South Humboldt Bay, Humboldt County, California – USA), CASIZ 108719 (~ 10 cm in diameter, 17.ix.1966, 4% formaldehyde solution, Monterey Bay, California – USA), CASIZ 108760 (as Chrysaora sp. , ~ 15 cm in diameter, 08.i.1969, 4% formaldehyde solution, Oregon – USA), CASIZ 163306 (~ 7 cm in diameter, 24.iii.2001, 4% formaldehyde solution, Ballena Bay Isle, San Francisco Bay, California – USA), CASIZ 163307 (~ 7 cm in diameter, 24.iii.2001, 4% formaldehyde solution, Treasure Island, San Francisco Bay, California – USA), CASIZ 163308 (~ 10 cm in diameter, 31.iii.2001, 4% formaldehyde solution, Horse Shoe Cove, San Francisco Bay, California – USA), CASIZ 163309 (~2,5 cm in diameter, 24.iii.2001, 4% formaldehyde solution, Ballena Bay Isle, San Francisco Bay, California – USA), CASIZ 163310 (~ 10 cm in diameter, 24.iii.2001, 4% formaldehyde solution, Coyote Point Marina, San Francisco Bay, California – USA); NNM 5238 (as Chrysaora helvola , ~ 13 cm in diameter, 4% formaldehyde solution, Nanaimo, British Columbia – Canada); USNM 54330 (as Chrysaora sp. , specimens ~3, 5 and 6 cm in diameter, 13.vii.1973, 4% formaldehyde solution, Oregon – USA), USNM 58901 (~ 25 cm in diameter, no date, 4% formaldehyde solution, Monterey Bay, California – USA), USNM 58902 (~ 11 cm in diameter, 26.ix.1978, 4% formaldehyde solution, Monterey Bay, California – USA).

Type locality. Aleutian Islands , Bering Sea , Alaska – USA ( North Pacific Ocean ) from the original description; Monterey Bay, California – USA (northeast Pacific Ocean) from the neotype specimen .

Distribution. Northeast Pacific Ocean (from Aleutian Islands to California – USA) ( Fig. 76).

Diagnosis. Living medusae of medium size, up to 30 cm in bell diameter; marginal lappets rounded (adults), 4 per octant, without canals; tentacles 24 (3 per octant, 2-1-2); quadralinga absent; colouration (adults) yellowish-brown or reddish-brown, darker near margin; some specimens may present lighter radial stripes.

Neotype specimen description. USNM 18943 as Chrysaora gilberti . Umbrella hemispherical, slightly flat (maybe due to preservation), ~ 8 cm in diameter. Exumbrellar surface finely granulated (small papillae). Mesoglea flexible. Marginal lappets 4 per octant (2 rhopalar and 2 tentacular), rounded; without canals of gastrovascular system. Rhopalia 8, without ocelli, in deep clefts; exumbrellar sensory pit deep. Tentacles 24 (3 per octant), as long as bell diameter. Subumbrellar musculature not distinguishable. Brachial disc circular. Pillars evident. Subgenital ostia rounded, 1/3 bell diameter. Oral arms V-shaped, 2 times longer than umbrellar diameter. Central stomach circular, marginal region limited by insertion of radial septa. Stomach pouches 16, width uniform at basal part; tentacular pouches enlarged at 1/5 distal part. Radial septa thin, with rounded base; straight up to 1/5 of margin, then making an “S” (first thinning tentacular pouch, then enlarging it); ending near tentacular base at rhopalar lappet. Gastric filaments in 4 interradial fields. Quadralinga absent. Immature specimen.

Description of other specimens and additional data. Medusa: medusae up 30 cm in diameter; umbrella hemispherical ( Fig. 24), flatter in younger specimens. Exumbrella finely granulated (small papillae); colouration yellowish-brown or reddish-brown, darker near margin ( Figs 24 –25), 16–32 clearer radial stripes may be present arising from apical ring. Mesoglea flexible, thicker centrally. Marginal lappets (in adults) rounded (semi-circular), 4 per octant, without canals of gastrovascular system; rhopalar lappets slightly smaller; margin of rhopalar lappets not overlapping (“open rhopalia” condition); rounded in younger specimens (up to ~ 6 cm in diameter). Rhopalia 8, without ocelli, in deep clefts; exumbrellar sensory pit deep. Tentacles 24 (3 per octant) (Fig. 26); 3–4 times longer than umbrellar diameter; reddish. Radial and circular musculature not distinguishable. Brachial disc circular. Pillars evident. Quadralinga absent. Subgenital ostia rounded to triangular, 1/4–1/6 of umbrellar diameter. Oral arms up to 6 times longer than umbrellar diameter, V-shaped, with strong frilled free edges, spirally coiled ( Fig. 24). Central stomach circular; margin limited by insertion of radial septa. Stomach pouches 16, width uniform at basal part; tentacular pouches enlarged at 1/5 distal part. Radial septa thin; rounded at base; straight up to 1/4 of margin, then making an “S” (first thinning tentacular pouch, then enlarging it); ending near tentacular base at rhopalar lappet (Fig. 26). Gastric filaments in 4 interradial fields. Gonads encircling gastric filaments, forming a semi-circular ring, heavily folded. Planula: no available data. Scyphistoma (Fig. 27): conical to goblet-shaped, 2–3 mm in height; oral disc 1–1.5 mm wide; typically with 16 tentacles, length up to 3 times polyp height; cruciform mouth with prominent lips elevated in relation to oral disc; gastric septa 4; whitish. Podocysts: trapezoid, 0.5 mm wide; yellowish-brown. Strobila: polydisc (more than 25 ephyrae), pale orange, strobilation lasts almost 20 days. Ephyra (Fig. 28): typically with 8 arms (lobes); 16 pointed marginal lappets, with rounded tips; 8 rhopalia with white concretions; 1.5–2 mm in diameter after release; pale orange; with nematocyst concentration on each side of rhopalia (on lappets), ring of nematocysts concentrations on central part of exumbrella, encircling the manubrium. Cnidome ( Fig. 88): Specimen USNM 18943 (neotype), medusa tentacles with holotrichous O-isorhizas [n=10; 11.7– 15.6 x 9.8–12.7 µm (mean = 14.01 x 11.27 µm)]; holotrichous a-isorhizas [n=10; 3.9–4.9 x 1.9–2.9 µm (mean = 4.8 x 2.54 µm)]; holotrichous A-isorhizas [n=10; 13.7–17.6 x 5.8–6.8 µm (mean = 15.88 x 6.56 µm)]; heterotrichous microbasic rhopaloids [n=10; 9.8–10.7 x 4.9–6.8 µm (mean = 10.48 x 5.78 µm)]; Specimen CASIZ 163310, medusa tentacles with holotrichous O-isorhizas [n=10; 9.8–11.7 x 8.8–9.8 µm (mean = 10.19 x 9.7 µm)]; holotrichous a-isorhizas [n=10; 5.8 x 2.9–3.9 µm (mean = 5.8 x 3.03 µm)]; holotrichous Aisorhizas [n=10; 11.7–14.7 x 5.8–6.8 µm (mean = 13.43 x 6.27 µm)]; heterotrichous microbasic rhopaloids [n=10; 9.8–11.7 x 4.9–5.8 µm (mean = 10.68 x 5.68 µm)].

Systematic remarks. The species was first described by Brandt (1835), who later referred it to the synonymy of C. helvola ( Brandt 1838) . Probably following Brandt’s indication and preference for the newer name, subsequent authors abandoned the older name fuscescens , using only the junior synonym helvola . The specific name fuscescens was only used by the author of the species ( Brandt 1835; 1838) and Haeckel (1880); the name re-appeared in the literature only after 96 years ( Shenker 1984). Shenker (1984: 623, 626), quoting a presentation by R.J. Larson in the 1977 Coelenterate Colloquium at the Museum of Natural History, Santa Barbara, California, remarked on the existence of two distinct species of Chrysaora in the northeast Pacific ( C. melanaster in Alaskan waters, and C. fuscescens more southerly). After Shenker resurrected the specific name fuscescens (based on Larson’s opinion), he was followed by many authors. Some years later, Larson (1990: 552) explained the historical aspects of the species name, and presented a taxonomic explanation for the correct use of the specific name. The species C. fuscescens and C. melanaster are very similar, both with three tentacles per octant and without quadralinga. The presumptive distribution of C. fuscescens is from California to Washington, whereas C. melanaster occurs from Oregon to Alaska ( Wrobel & Mills 1998). However, the species are morphologically different. Chrysaora melanaster has small canals of the gastrovascular system penetrating the marginal lappets, and these canals are not present in C. fuscescens . Literature data on living animals ( Brandt 1835; Wrobel & Mills 1998) and personal communications from other researchers (Claudia Mills, Chad Widmer, both in 2006) corroborate the distinction of the species; C. fuscescens has a brownish to orange colouration, rarely with radial markings, and C. melanaster almost always possesses radial markings and dark radial lines on the subumbrella. Unfortunately, preserved specimens loose most of their colouration and, therefore, this character is less useful for preserved materials.

Biological data. The species is widely known from public aquaria in USA, and its life cycle was described by Widmer (2008b). Additional information on different life cycle stages is available sparsely in the literature (e.g. Wrobel & Mills 1998; Gershwin & Collins 2002).

Etymology. fuscescens : due to brown colouration, derived from the Greek fuscus (brown; dark) ( Brown 1956).