Sphaerocoryne bedoti Pictet, 1893

Maggioni, Davide, Schuchert, Peter, Arrigoni, Roberto, Hoeksema, Bert W., Huang, Danwei, Strona, Giovanni, Seveso, Davide, Berumen, Michael L., Montalbetti, Enrico, Collins, Richard, Galli, Paolo & Montano, Simone, 2021, Integrative systematics illuminates the relationships in two sponge-associated hydrozoan families (Capitata: Sphaerocorynidae and Zancleopsidae), Contributions to Zoology 90, pp. 487-525 : 498-499

Sphaerocoryne bedoti Pictet, 1893

Sphaerocoryne bedoti Pictet, 1893: 10 , pl. 1 figs. 5–6 ; Millard, 1975: 54, fig. 20e; Wedler & Larson, 1986: 80, fig. 3 Ca-b; Hirohito, 1988: 37, fig. 11d ; Galea, 2008: 13 , fig. 3f ; Schuchert, 2010: 467, fig. 10 a-f; Nagale & Apte, 2014: 1, fig. 2 a-d.

Clavatella multitentaculata Warren, 1908: 278 , pl. XLV figs. 7–9 .

Syncoryne flexibilis Fraser, 1938: 15 , pl. II fig. 8 .

Sphaerocoryne multitentaculata . Yamada & Konno, 1973: 104, figs. 1–3 .

Sphaerocoryne cf. agassizii . Miglietta et al. 2018: 106, suppl. data, p. 27.

Examined material: Sample BT 007, Panama, August 2015, polyps in ethanol. – Sample BT 030 Panama, August 2015, polyps in ethanol. – Sample FB 021, Saudi Arabia, 01/05/2017, polyps in ethanol and formalin. - Sample FB 073, Saudi Arabia, 02/05/2017, polyps in ethanol and formalin. – Sample FB 098, Saudi Arabia, 02/05/2017, polyps in ethanol. – Sample FB 154, Saudi Arabia, 03/05/2017, polyps in ethanol. – Sample FB 300, Saudi Arabia, 05/05/2017, polyps in ethanol and formalin. – Sample FB314, 05/05/2017, polyps in ethanol and formalin. – Sample KA 062, Saudi Arabia, 15/12/2015, polyps in ethanol. – Sample mh201, Maldives, January 2015, polyps in ethanol and formalin. – Sample sp003, Maldives, April 2015, polyps in ethanol. – Sample MA 16002, Maldives, 19/01/2016, polyps in ethanol and formalin. – Sample MA 16031, Maldives, 27/01/2016, polyps in ethanol. – Sample MA 16056, Maldives, 09/02/2016, polyps in ethanol and formalin. – Sample MA 16057, Maldives, 09/02/2016, polyps in ethanol and formalin. – Sample MA 16058, Maldives, 09/02/2016, polyps in ethanol and formalin. – Sample MA 1016020, Maldives, 14/10/2016, polyps in ethanol and formalin. – Sample MA 0117107, Maldives, 09/02/2017, polyps in ethanol and formalin. – Sample MA 0117118, Maldives, 09/02/2017, polyps in ethanol and formalin (MHNG-INVE-0137431). – Sample STE025, Sint Eustatius, 14/06/2015, polyps in ethanol. – Sample MHNG-INVE-0060977, Guadeloupe, 23/03/2008, polyps in ethanol. – Sample MHNG-INVE-0071921, June 2010, Madeira, polyps in ethanol.

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Description: Polyp. Colonies monomorphic, living in association with sponges and occasionally with encrusting algae ( figs. 2 A-B). Hydrorhiza tubular, branched, covered by perisarc and growing within the sponge host. Pedicels long (up to 4 mm), unbranched, covered by a slightly wrinkled, thin perisarc ( fig. 2A ) and occasionally covered by debris ( fig. 2B ). Hydranth pyriform, up to 2 mm long, with variable diameter (130–510 Μm) ( figs. 2 A-E). Hypostome proboscis-like, contractile, with a band of nematocysts below the mouth ( fig. 2F ), with a highly extensible mouth ( fig. 2G ). Up to 40 tentacles with no evident arrangement and closely scattered in the broadest part of the hydranth ( figs. 2D, E ). Each tentacle with a terminal, nematocyst-rich capitulum (diameter: 110–140 Μm in the distal whorls; 70–85 Μm in the proximal whorls), with a central inclusion ( fig. 2H ). Tentacles up to 1 mm long in the distal whorls and shorter in the proximal whorl. Up to six clusters of 5–20 medusa buds at the same stage of maturation developing above distal tentacles ( figs. 2C, I ), marked by a red pigmented band ( fig. 2E, J ). In some instances, tentacles disappear in polyps bearing medusa buds (reproductive exhaustion) ( fig. 2K ). Living hydranths with white, or yellowish hypostome, a regular bright red band below the hypostome, gastric cavity transparent or yellowish in the broadest part and whitish below the broadest part of polyps ( figs. 2 A-E). Desmonemes ( fig. 2M ), small stenoteles ( fig. 2M ) and large stenoteles ( fig. 2N ) occurring simultaneously and concentrated in the capitula, and rarely scattered in the hydrorhiza and in the hydranth; heteronemes ( fig. 2O ) in the hydrocaulus and hydrorhiza; small stenoteles in a band around the hypostome.

Newly liberated medusa. Small, 105–170 Μm wide and 110–200 Μm high, with nematocysts scattered on the exumbrella ( fig. 2L ). Manubrium short, 40–50 Μm long and 80–110 wide at the base, with a circular mouth. No radial canals visible, and four small triangular bulbs. When released, medusae with no tentacles; six days after release, medusae of the same size, with four short tentacles, 40–50 Μm long. Living medusae transparent with reddish bulbs. Desmonemes and small stenoteles scattered on the exumbrella.

Polyp and newly liberated medusa cnidome. i) Desmonemes (undischarged: 10–12 × 5–6 Μm; discharged capsule: 10–11 × 5–6 Μm). ii) Heteronemes (undischarged: 20–22 × 8–10 Μm). iii) Large stenoteles (undischarged: 25–28 × 18–20 Μm; discharged capsule: 20–21 × 14–16 Μm). iv) Small stenoteles (undischarged: 10–12 × 8–10 Μm; discharged capsule: 10 × 6 Μm).

Distribution: Atlantic Ocean and Caribbean Sea (Madeira; Guadeloupe, Panama, Puerto Rico, Sint Eustatius), Red Sea and Indo-West Pacific ( Saudi Arabia; India, Indonesia, Maldives, South Africa), and East Pacific ( Colombia, Ecuador, Mexico, Panama, Japan).

Remarks:This species was initially described by Pictet (1893) based on polyp stage alone. The most striking difference to other sphaerocorynid species is the typical colouration of the polyp and the medusa buds forming large clusters, as already noted by Warren (1908). According to previous descriptions, polyps of S. bedoti and S. agassizii appear very similar, the latter nevertheless not being thoroughly characterised in the original description by McCrady (1859). A possible difference between S. agassizii and other sphaerocorynid species is the presence of two opposite tentacles in medusa buds and newly released medusae, as described for instance in Pictet (1893), Hargitt (1904), and Calder (1971), something never observed in the species investigated herein. Medusa buds and newly released medusae in S. bedoti are small in size and with no developed tentacles or ocelli, as depicted by Yamada & Konno (1973) and in the present work. Most of the differences between S. bedoti and S. agassizii occur in the adult medusa, specifically in the exumbrellar nematocyst rows and in the tentacular nematocyst clusters ( Schuchert, 2010). However, adult medusae clearly ascribable to S. bedoti and S.agassizii could not be collected for the present work, and, therefore, the status of the two species and the consequent taxonomic implications related to the validity of the genera Sphaerocoryne and Corynetes must remain unresolved. The paucity of reliable diagnostic characters in the polyp stage of sphaerocorynid species has led to subsequent confusion in species identifications in the family, and many records should be considered dubious due to the lack of thorough descriptions, drawings and photos of colonies, or genetic data. Therefore, we abstain from including these records as synonyms.

Figures

FIGURE 1 Phylogenetic hypotheses for the Sphaerocorynidae and Zancleopsidae.A) Sampling localities.B) Phylogenetic reconstruction of the Capitata based on the concatenated multi-locus dataset, with numbers at nodes representing ML bootstrap values, Bayesian posterior probabilities, and MP bootstrap values, respectively; asterisks denote maximal support for all analyses, whereas dashes denote absence of the node in the analysis; samples corresponding to medusa stages are highlighted in grey. C) Species tree of the Sphaerocorynidae and Zancleopsidae, with numbers at nodes representing Bayesian posterior probabilities.

FIGURE 2 Sphaerocoryne bedoti. Polyps from A, B) Maldives and C) Sint Eustatius. D) Tentacles organisation. E) Close-up of a hydranth showing the typical colouration.F) Hypostome, with a nematocyst band (arrowhead).G) Living polyp detached from the host and trying to ingest a portion of the host sponge.H) Capitulum with a central inclusion.I) Polyp with medusa buds organised in clusters.J) Close-up of a polyps with medusa buds clusters arising from the red band area. K) Polyp with medusa buds showing reproductive exhaustion.L) Newly released medusa.M) Desmonemes (d) and small stenoteles (ss) from the polyp. N) Large stenoteles (ls) and small stenoteles (ss) from the polyp. O) Heteroneme from the polyp.Scale bars: A, B) 0.5 mm; C-G, I-K) 0.2 mm; H, L) 25 Μm; M-O) 5 Μm.

FIGURE 3 Kudacoryne diaphana. Polyps from A, B) Red Sea and C, D) Maldives.E) Hypostome. F) Capitulum.G) Polyps with medusa buds a few hours before release. H) Newly released medusa. I) Large stenoteles (ls), small stenoteles (ss), and desmonemes (d) from the polyp stage.J) Macrobasic mastigophore from the polyp stage.K) Small stenoteles (ss) and microbasic mastigophores (mi) from the newly released medusa.Scale bars: A-D,G) 0.2 mm; E, H) 50 µm; F) 20 µm; I-K) 5 µm.

FIGURE 5 Euphysilla sp. A, B) Ethanol-fixed polyps from Martinique.C) Desmonemes, D) small and E) large stenoteles, and F) heteronemes from the polyp. Scale bars:A, B) 50 Μm;C-F) 5 Μm.

FIGURE 6 Heterocoryne caribbensis. A-C) Polyps from Sint Eustatius. D, E) Tentacles partially fused. F) Large stenoteles (ls), small stenoteles (ss), and desmonemes (d). Scale bars: A-C) 0.5 mm; D, E) 0.1 mm; F) 5 Μm.

FIGURE 7 Zancleopsis dichotoma. A) Polyp from Singapore (fixed in formalin).B) Close-up of a polyp.C) Tentacle with terminal and sub-terminal capitula.D) Large stenoteles (ls), small stenoteles (ss), desmonemes (d), and microbasic euryteles (e). E) Discharged microbasic eurytele. F, G) Medusae.Details of the H) manubrium with gonads and I) tentacles.Scale bars: A-C) 0.1 mm; D, E) 5 Μm;F-I) ~ 0.3 mm.

FIGURE 8 Zancleopsis cabela. Polyps from A) Saudi Arabia and B, C) Maldives.D) Tentacle with terminal and sub-terminal capitula. E) Maldivian polyp with medusa buds.F) Large stenoteles (ls), medium-sized stenoteles (ms), small stenoteles (ss), and desmonemes (d). G) small stenoteles (ss) and microbasic euryteles (e). H, I) Female and male medusae, respectively. Details of J) manubrium with female gonads and K) tentacles. Scale bars:A-C, E) 0.2 mm; D) 50 Μm;F, G) 5 Μm; H-K) ~ 1 mm.

FIGURE 9 Zancleopsis sp. A-C) Polyps from Singapore.D) Close-up of a polyp. E) Tentacle with terminal and subterminal capitula.F) Large stenoteles (ls), small stenoteles (ss), and desmonemes (d). G) undischarged and H) discharged microbasic eurytele.Scale bars: A-D) 0.2 mm; E) 20 Μm; F-H) 5 Μm.

FIGURE 10 Distributional maps of each analysed species.A) Sphaerocoryne bedoti. B) Euphysilla pyramidata. C) Kudacoryne diaphana. D) Euphysilla sp. E) Heterocoryne caribbensis. F) Zancleopsis cabela. G) Zancleopsis dichotoma. H) Zancleopsis sp.Red circles represent data from this study, whereas blue diamonds represent data from literature.

FIGURE 11 Most parsimonious median-joining haplotype networks based on the 16S of A) S.bedoti, B) E.pyramidata, and C) K.diaphana, with haplotypes coloured by locality, as shown in the legend.