Eirene menoni Kramp, 1953

Crow, Gerald L., Holland, Brenden S., Yamamoto, Gaku, Ikeda, Shuhei, Adachi, Aya & Niide, Kelley, 2023, Tuerkayana rotundum, Zoological Studies 62 (49), pp. 1-15 : 5-8

Eirene menoni Kramp, 1953

Menon’s hydromedusa

Eirene-Kurage

Type locality. Great Barrier Reef , outside Trinity Harbor, near Cairns, Queensland, Australia (~ 16°S, 146°E), water temperature 25.7°C, at 32 m depth. One specimen captured 5 Dec 1928. Holotype deposited in Natural History Museum, London, UK [British Museum Natural History BMNH 1954.3.4.559] (Not seen).

Material examined

Medusae- SAMA H3614 (4 specimens) wild collected Aldinga Reef, South Australia, 12 Feb 1961 [ Fig. 2A ] (see Kramp 1965). SAMA H3615 (1 specimen, 10.6 mm bell width) wild collected between Hopkins and Thistle Islands, South Australia, 01 Jan 1964 collected by Ronald Vernon Southcott ( Fig. 2B ). SAMA H1605 (1 specimen, current 13.38 mm bell diameter) wild collected Pumicestone Passage, Moreton Bay, Queensland, Australia (~ 27.6°S, 153°E), Feb 2000 - collected by Puk Petersen. NSMT-Co 1808 (9-specimens) wild collected Shonan Fishing Port, Kanagawa Prefecture, Japan (35.17°N, 139.28°E), collected near surface 12 Sept 2021, Gaku Yamamoto collector. NSMT-Co 1810 (1 specimen) medusa Kamo Aquarium, Shuhei Ikeda collector. NSMT-Co 1811 (1 specimen) medusa Kamo Aquarium, Shuhei Ikeda collector. NSMT-Co 1812 (1 specimen) medusa Kamo Aquarium, S. Ikeda collector.

Polyps- NSMT-Co 1809 cultured colony Kamo Aquarium preserved 1 Oct 2021, transferred from Enoshima Aquarium 31 Jan 2007 [Shuhei Ikeda, pers comm].

GenBank sequences - for E. menoni (see Table 1).

Amended species description

After Kramp (1953) original description, modified by Bouillon (1984) description of polyp, Bouillon (1995), and this study. Medusae-Bell more flat than bell shaped; Bell diameter usually 12 mm may reach 20 mm, narrow tubular peduncle extending basically same size down to manubrium ( Fig. 3A ), manubrium and oral “lips” exceed bell height in living specimens, oral “lips” strap-like in young specimens less than 3.2 mm bell diameter ( Fig. 3B ), four radial canals with gonads that begin to develop in mid-radial canal and extend to the bell ring canal ( Fig. 3B–D ), variability of gonad formation was described by Kramp (1953) based on one specimen with gonads extending from the base of the peduncle almost to the ring canal. Kramp (1965) reported that gonadal length was variable and in Victoria, South Australia specimens extends from near the radial ring canal to more than half the distance to the base of the peduncle. Sugiura (1979) illustrated and stated, “gonads begin to be formed on the radial canals neighboring the basal part of the stomachal peduncle and with growth of the medusa they gradually elongate downwards and widen along the radial canal.” Marginal tentacles typically same length, and about 48 in number, may reach 54 with some small developing marginal tentacles. Fully formed tentacle number from Sagami Bay, Japan varies from 16 to 20 in 3.2–5.1 mm bell diameter and 30 to 36 in 5.2–8.0 mm bell diameter specimens. Color of tentacle bulb and between bases of the four oral “lips” varies from green, reddish brown to dark brown. No cirri, excretory papillae or rudimentary bulbs (warts) are present on ring canal, canal contains 1–3 statocysts between successive tentacles (not visible after preservation). Reproduction through a polyp and planula stage. Cnidome composed of elongated fusiform microbasic mastigophores, measuring 10.5 × 3.0 µm to 9.0 × 2.5 µm. Typically found near surface, often near rivers or estuaries, down to a depth of 51 m.

Polyps (live and fixed) - Released planula settle at 24 hours and differentiates in polyp stage after three days. Attached planula forms stolonal colonies, arising from creeping hydrorhiza. Hydrorhizal stolons long, slender with distance between polyps ( Fig. 3E ), hydrothecal pedicels with a thin annulated hydrocaulus that extend in a strong, extensible polyp. The polyp grows erect with a long hydrocaulus, hydranths can be large or reduced, narrowest at base, gastric region typically vase-to slightly club-shaped, constricted short distance below tentacular whorl, constriction usually pronounced but sometimes, indistinct, hydranth expanding again at the distal end, here becoming subspherical to knob-shaped ( Fig. 3E, F ) supporting whorl of tentacles; tentacles filiform, in one whorl, 10 marginal tentacles; their bases with intertentacular web. Hydroid hydranth tentacles when disturbed or preserved retract almost completely into the hydrotheca ( Fig. 3E ). Gonotheca unknown. Polyps appear as “campanulinida” type. The polyp cnidome is represented by elliptical atrichs measuring 6.0 × 2.5 µm to 5.0 × 2.0 µm.

Indo-Pacific Ocean biogeographic distribution for 21-records of Eirene menoni [alphabetized by geographic source with map numbers] ( Fig. 4 ).

Australia - (1) Trinity Harbor, Cairns [~ 16°S, 146°E], (7) Sydney, NSW [~ 33.8°S, 151.2°E], (11) North Cape, Northern Territory [10°S, 143°E], (12) Moreton Bay, Queensland [27.3°S, 153.3°E], (17) Aldinga Reef, Gulf of Saint Vincent [35.16°S, 138.46°E], (18) Broome, North West Territory [17.96°S, 122.24°E], ( Kramp 1953; Kramp 1965; Gershwin et al. 2010). China - (2) Chengshan [37.2°N, 122.2°E], (as Phortis lactea ) (3) Daya Bay [22.4°N, 114.4°E], (4) Xaimen Bay [24°N, 118°E], (5) Zhujiang River Estuary [36.1°N, 120.3°E], (15) Beibu Gulf [20.85°N, 109.26°E], ( Ling 1936 –1937; Du et al. 2010; Zheng et al. 2014; Zhang et al. 2015). India - (19, 20) Puri, Odisha [19.8°N, 85.5°E], Chennai [Madras] [13.1°N, 80.2°E] (as Phortis sp. ), ( Menon 1932; Kramp 1955). Japan - (8) Aitsu Marine Biological Station, Kumamoto Prefecture, Kyushu [32.8°N, 130.7°E]; (9) Shonan Fishing Port, Kanagawa Prefecture, Honshu [35°N, 139.5°E this study], (16) Hamanako, Shizuoka Prefecture, Honshu [34.4°N, 137.3°E], (21) Northern Oita Prefecture, Kyushu [~ 33.3°N, 131.2°E] ( Sugiura 1979; Sakiyama and Adachi 2001; Okamoto et al. 2016; Iwai 2021). Papua New Guinea - (10) Laing Island [5.3°S, 147.1°E], ( Bouillon 1984). New Zealand - (13) North Island [35.18°S, 174.17°E], ( Bouillon 1995). South Korea - (14) Chunjangdae [36.2°N, 126.5°E], Park 1996). Vietnam - (6) Nha Trang [12.3°N, 126.5°E], ( Kramp 1962). This species is widespread throughout the Indo-Pacific.

Figures

Fig. 2. Eirene menoni medusa Australia images. (A) SAMA H3614 (current bell width 14.2 mm) collected 12 Feb 1961 at Aldinga Reef, Victoria, South Australia and identified by Paul Kramp. (B) SAMA H3615 (current bell width 10.6 mm) collected 1 Jan 1964 between Hopkins and Thistle Islands, Victoria, South Australia and identified by Ronald V. Southcott. Images courtesy of the South Australian Museum (Shirley Sorokin, Andrea Crowther and Peter Hunt).

Fig. 3. Eirene menoni medusae and polyps Japan images. Medusae (A–D) are images from preserved specimens NMST-Co 1808 originally collected at Shonan Fishing Port, Kanagawa Prefecture, Japan (collected by Gaku Yamamoto). Polyps (E–F) are images of preserved cultured specimens NMST-Co 1809 from the Kamo Aquarium, Japan (collected by Shuhei Ikeda). Image (E) retracted tentacles on the long hydrocaulus and (F) shape of hydrotheca buds. Scale bars: A–D = 1 mm; E–F = 0.125 mm.

Fig. 4. Biogeographical map showing validated wild capture distribution records for Eirene menoni and Eirene lacteoides. Eirene menoni records that are indicated by red triangle refer to holotype location, green circles refer to localities with COI mtDNA sequences, and yellow squares refer to localities obtained from published studies with sufficient description detail or documentation. Eirene lacteoides records are indicated by a blue diamond. The GPS data for these records is located under the specific species in the text. Specimens with public aquaria captive culture locations are referred to in the manuscript text.