Aurelia, COERULEA VON LENDENFELD, 1884

Scorrano, Simonetta, Aglieri, Giorgio, Boero, Ferdinando, Dawson, Michael N. & Piraino, Stefano, 2017, Unmasking Aurelia species in the Mediterranean Sea: an integrative morphometric and molecular approach, Zoological Journal of the Linnean Society 180 (5), pp. 243-267 : 255-259

AURELIA COERULEA VON LENDENFELD, 1884

Aurelia coerulea von Lendenfeld, 1884: 280 – 281 . Type locality: Port Jackson , Australia.

Aurelia japonica Kishinouye, 1891: 289 – 291 , fig. unnumbered. Type locality: Tokyo Bay, Japan. Aurelia sp. 1 Dawson & Jacobs, 2001: 93 (Newport Beach, California, USA). Dawson, 2003: 375 – 376 (Tokyo Bay, northern Japan, Australia, Atlantic, Mediterranean coast of France, and east coast of USA).

Aurelia UBI lineage Schroth et al., 2002: 4 (table 2) (California, USA; Atlantic and Mediterranean coasts of France; Australia, Indian Ocean; Japan).

Material examined: Holotype: Female medusa, VL, 13 September 2011, 132 mm BD, deposited in UNIPD. Accession number: CN56 CH.

Paratype I: Female medusa, VL, 13 September 2011, 136 mm BD, deposited in UNIS _SCY. Accession number: UNIS _SCY_011 .

Paratype II: Female medusa, EH, 15 October 2013, 85 mm BD, deposited in UNIS _SCY. Accession number: UNIS _SCY_012 .

Other material: Eight medusae, VL, 13 September 2011, 107 – 143 mm BD deposited in UNIS _SCY. Accession numbers: UNIS _SCY_013 – 020 .

Other material: Seven medusae, EH, 15 October 2013, 38 – 80 mm (range of BD) deposited in UNI- S_SCY. Accession numbers: UNIS _SCY_021 – 027. Specimens of polyps and ephyrae were examined but not preserved nor registered.

Description (based on holotype and paratypes): Morphometric and meristic data for polyp and ephyra stages are shown in Table 2. Morphology is illustrated in Figures 5A, 6, 8A – J, 9A, B, 10A, B, and 11A – D. Molecular diagnosis is presented in Figures 3 and 4.

Polyp: Tentacles 16 – 22. Tentacle diameter uniform or slightly decreasing along the proximal – distal axis. Hypostome cruciform ( Figure 9A, B). Colour pinkish. Asexual reproduction by budding from stolon ( Fig. 10A) or directly from the column of parental polyp. Rarely podocyst originates at the base of pedal disc or along the stolon. External free-swimming propagules (EFSPs) and internal free-swimming propagules (IFSPs; Vagelli, 2007) observed, with EFSP more common ( Fig. 10B). Strobilation polydisc, with up to 17 discs observed.

Ephyra: Normally eight arms, 16 marginal lappets, and eight rhopalia. Marginal lappets with breadknife-like shape ( Fig. 8A, F), both margins rounded, or sharpened (internal margin, rhopaliar side). Dark orange – brownish. Young ephyrae: without gastric filaments at liberation. Manubrium cruciform and oral arms developing during the second week ( Fig. 8C, H).

Medusa: Disc flattened, up to 26 cm BD. Bell shape typically concave, or undulating, eight marginal lobes (occasionally 16 when BD> 11 cm), eight marginal rhopalia in shallow clefts (f29, 3.5 ƚ 0.35 mm), but deeper than non-rhopalial clefts (if present), where the adradial canals join the bell margin.

Sense organ protected on the exumbrellar side by a triangular dorsal hood ( Fig. 11A). Long rhopalium directed towards the bell margin ( Fig. 11B). The ectodermal ocellus is a small protuberance with a dense concentration of reddish pigment granules ( Fig. 11C). A large endodermal ocellus on the subumbrellar side at the base of lithocyst ( Fig. 11C) with reddish pigment granules arranged in a circular shape around the perimeter ( Fig. 11D).

Numerous small whitish tentacles arranged slightly above the bell margin. Manubrium cruciform, rigid, large, 2 – 14 mm depth, width 8 – 28 mm, bearing four perradial, folded oral arms, with mean length (f5) 4 r /5.

Four (occasionally between five and seven) interradial gonads, horseshoe-shaped. Planulae brooded on the oral arms. Relative to the gastric tissue, the subgenital pore is placed centrally to or, in smaller medusae, adjacent to but circumscribed by the gastric filaments ( Fig. 6). Subgenital pore diameter (f11) 1 – 6 mm. Opposite gastric cavities distant across the diameter. Gastric diameter highly variable: proximal (f9) ranging from r /6 to r /3; distal (f10) ranging from r /2 to 6 r /7. From each gastrogenital sinus between seven and ten broad canals depart (range of variation: two or three perradials, two or three adradials, and three or four interradials). Interradial and perradial canals branched, frequently anastomosed in the second and third distal of the bell. Number of perradial (f26) and interradial (f27) anastomoses: 14 – 48 and 13 – 51, respectively. Adradial canals (f28) mostly unbranched, moderately connected to the canal mesh both in the distal or proximal portion ( Fig. 5A).

Type locality: Port Jackson ( Australia).

Habitat: In the Mediterranean Sea, apparently restricted to euryhaline and eurythermal coastal lagoons, marinas, and harbours.

Distribution in the Mediterranean Sea: Including at least VL (Adriatic Sea), EH (Balearic Sea), and SL (Thyrrenian Sea).

Distribution outside the Mediterranean Sea: Reported from Japan (Miyazu Bay, Sakata Bay, Uwa Bay, Ondo Strait, Tokyo Bay), Korea (Incheon, Geojedo, Busan), California (Long Beach, Marina del Rey, Newport Beach, San Diego), and numerous sites throughout the Australian coast, from Queensland to New South Wales and Western Australia ( Dawson & Jacobs, 2001; Dawson, 2003; Ki et al., 2008). Few DNA sequences clustering into the A. coerulea clade were previously obtained from samples collected in the eastern Atlantic and Mediterranean coastal areas of France ( Schroth et al., 2002).

Remarks: Within the genus Aurelia , A. coerulea is the taxon with the broadest world distribution. The type locality is not coincident with its inferred biogeographic origin of the Western Pacific coastal waters ( Dawson et al., 2005). The name A. coerulea has priority over its junior synonym Aurelia japonica ( Kishinouye, 1891) .

AURELIA RELICTA SCORRANO, AGLIERI, BOERO ,

DAWSON & PIRAINO SP. NOV.

Aurelia sp. Benović et al., 2000: 202, fig. 7 (Mljet lakes, Croatia).

Aurelia sp. 5 Dawson & Jacobs, 2001: 93 (Mljet). Ram̃sak et al., 2012: 70 (South Adriatic, Mljet lakes). Aurelia MS-MKL lineage Schroth et al., 2002: 4 (table 2) (Mljet lakes, Croatia).

Material examined: Holotype: Immature, ML, June 2013, 76 mm BD. Deposited in UNIPD. Accession number: CN 57 CH.

Paratype I: Immature, ML, June 2013, 66 mm BD. Accession number: UNIS _SCY_028.

Paratype II: Immature, ML, June 2013, 68 mm BD. Accession number: UNIS _SCY_029.

Other material: Six medusae, ML, June 2013, 58 – 130 mm (range of BD); three medusae, ML, February 2013, 70 – 95 mm (range of BD). Accession numbers: UNIS _SCY_030 – 038.

Description (based on holotype, paratypes, with additional data on mature jellyfish from Benović et al., 2000): Morphometric and meristic data for polyp and ephyra stages are presented in Table 2. Morphology is illustrated in Figures 5B, 8K – O, 9C, 10C, D, and 11E – H. Molecular diagnosis is presented in Figures 3 and 4.

Polyp: Tentacles typically 16. Only two polyps (out of 30) with 14 and 22 tentacles observed. Tip of tentacles thickened. Hypostome dome-shaped. Colour whitish – pinkish.

Main asexual reproduction by budding from stolon or directly from the column of parental polyp. Rarely podocyst originates at the base of pedal disc or along the stolon. Ciliated IFSPs (from gastrovascular cavity or stolon) frequently liberated ( Fig. 10D, arrow), exhibiting a slight rotatory (planula-like) movement for 1 – 3 days, before final settlement and development into polyp. EFSPs also observed. Asexual reproduction also through pseudoplanulae ( Fig. 10C, arrow; Hérouard, 1909; Piraino et al., 2004). Strobilation polydisc, up to 15 discs observed.

Ephyra: Normally eight arms, 16 marginal lappets, and eight rhopalia. Marginal lappets long, breadknifelike shaped ( Straehler-Pohl & Jarms, 2010), pointed at tip ( Fig. 8K). Colour milky – transparent. Manubrium cruciform, oral arms appearing during the second week of ephyra development. One or two gastric filaments per quadrant.

Medusa: Disc flat, whitish. Benović et al. (2000) reported BD up to 55 cm in diameter. Bell shape (f21), typically undulating or straight, with eight marginal lobes and eight marginal sense organs in a medium cleft (f29, 4.32 ƚ 0.3 mm).

The sense organ is protected on the exumbrellar side by a dorsal hood of triangular shape ( Fig. 11E). The rhopalium is long and directed towards the bell margin ( Fig. 11F). Long rhopaliar lappets are visible on both exumbrellar and sumbumbrellar sides ( Fig. 11E).

The ectodermal ocellus is small and appears as a protuberance with a dense concentration of reddish pigment granules ( Fig. 11G). A large endodermal ocellus is visible on the subumbrellar side at the base of the lithocyst ( Fig. 11G). The reddish pigment granules of the endodermal ocellus are arranged in a circular shape, with the dark reddish pigment granules around the perimeter ( Fig. 11H).

The sense organ is always surrounded by two thin branches of medium interradial canal, which turn into anastomoses (or not) with close canals in larger individuals.

Numerous small and whitish tentacles arranged slightly above the bell margin. Manubrium cruciform, rigid, depth 1 – 3 mm, width 8 – 21 mm, with four perradial oral arms slightly folded, mean length (f5) 7 r /9.

Four interradial gonads, horseshoe-shaped. Opposite gastric cavities close across the diameter; proximal gastric diameter (f9) ranging from r /7 to r /4; distal gastric diameter (f10) ranging from r /2 to 2 r /3. From each gastrogenital sinus, between six and nine thin canals (see also the development of canals in Fig. 8O) depart (ranges of variation: between two and four perradials, two adradials, and between one and five interradials). Perradial (f26) and interradial (f27) canals gradually branching and anastomosing (between ten and 27 times) in the distal third of the bell, creating a delicate mesh net. Adradial canals (f28) unbranched, occasionally one or two anastomoses are found.

Etymology: From the Latin relictus = abandoned, forsaken. The specific name refers to the ‘relict’ geographic isolation of this species.

Type locality: Veliko Jezero (Mljet Island, Adriatic Sea).

Habitat: Marine, neritic.

Distribution: Currently known from the type locality only.

Remarks: Within the genus Aurelia , Aurelia relicta sp. nov. has the smallest known distribution.