A tubulariid hydroid associated with anthozoan corals in the Mediterranean Sea

Figures & data

Table I. Known associations between hydroids and anthozoans

Species	Host	Locality	Reference
Ptilocodium repens	Ptilosarcus sinuosus	Timor Est	Coward 1909
Hydrichthella epigorgia	Anthoplexaura dimorpha, Bellonella rigida, Dendronephthya sp., Siphonogorgia sp.	Japan, Seychelles, Indonesia	Stechow 1909, Bouillon 1967, Hirohito 1988, Puce et al. 2008b
Sarsia medelae	Thouarella sp., Primnoisis sp., Notisis sp.	Antarctica	Gili et al. 2006
Ralpharia magnifica	Parerythropodium membranaceum	Australia	Watson 1980, 1984
Ralpharia coccinea	Parerythropodium membranaceum	Australia	Watson 1980, 1984
Ralpharia neira	Melitodes ochracea	Indonesia	Petersen 1990
Ralpharia gorgoniae	Gorgonia ventalina	Panama (Atlantic Ocean)	Petersen 1990
Ralpharia sanctisebastiani	Lophogorgia punicea	Brazil	da Silveira & Migotto 1984
Ralpharia parasitica	unidentified gorgonian	Philippines	Korotneff 1887, Petersen 1990
Asyncoryne philippina	unidentified gorgonians	La Réunion Islands	Boero et al. 1995
Pteroclava krempfi	Cladiella krempfi, unidentified gorgonian	Vietnam, Japan, Indonesia, Papua New Guinea, La Réunion Islands	Billard 1919, Hirohito 1988, Boero et al. 1995, Puce et al. 2008b
Zanclea timida	Paratelesto sp.	Indonesia	Puce et al. 2008b
Zanclea gilii	Unidentified scleractinian	Papua New Guinea	Boero et al. 2000
Zanclea sp.	Unidentified scleractinian	Seychelles	Millard & Bouillon 1973, Millard 1975
Zanclea margaritae	Acropora muricata	Australia	Pantos & Bythell 2010
Hybocodon cfr. prolifer	Madrepora oculata	Mediterranean Sea	Mastrototaro et al. 2009, Vertino et al. 2009
Ectopleura sp.	Antipathella subpinnata, Paramuricea clavata, Paramuricea macrospina, Eunicella cavolinii	Mediterranean Sea	Present study

Figure 1. Map of the sampling regions. Locations of the explored areas along the western Tyrrhenian coast: Ischia Island, shoal Secca dei Galli and S. Eufemia Gulf (black dots).

Figure 2. Description of Ectopleura sp. A, solitary polyp of Ectopleura sp. emerging from a branchlet of Antipathella subpinnata. Note the antipatharian polyps irregularly arranged on the hydroid stem. Inset: SEM close-up of the hydranth. B, solitary polyp of Ectopleura sp. emerging from a branchlet of Eunicella cavolinii. Inset: Close-up of the hydranth. C, transverse section of a hydrocaulus (hy) surrounded by the black coral (bc). Spines are visible on the golden skeleton of the coral (sk), while no divisions are found in the lumen of the hydroid. D, transverse section of a hydrocaulus (hy) surrounded by the gorgonian tissues (go). The gorgonian skeleton (sk), surrounded by the coenosarc bearing sclerites, covers the perisarc (p). Immature gonophores of Ectopleura sp. found in A. subpinnata (E) and E. cavolinii (white arrows) (F). Scale bars: B, 2 mm. A, B inset, 1 mm. A inset, 0.5 mm. C,D,F, 0.2 mm. E, 50 μm.

Figure 4. Relationship of Ectopleura sp. with the hosts. A, colony of Antipathella subpinnata characterised by a lax, non-arborescent ramification system. Several foreign elements (both sediment and epibionts) are visible dispersed on the branches (while arrows). B, hydroid polyp emerging perpendicularly from a black coral branchlet. C, hydrocaulus running along the black coral branchlet. D, naked hydrocaulus of Ectopleura sp. settled on Paramuricea clavata. E,F, Ectopleura sp. polyps settled on Paramuricea macrospina. G, hydroid polyp emerging perpendicularly from a branchlet of Eunicella cavolinii. H, peeled portion of E. cavolinii showing the place of settlement of the hydrocaulus. J, portion of hydrocaulus (hy) surrounded by the gorgonin layer (sk). K, perisarc of Ectopleura sp. covered by the spiny skeleton of A. subpinnata. Along the hydrocaulus diameter decreases are visible as skeleton constrictions, indicating different growing stages of the hydroid. L, SEM enlargement of the transversal section adjacent to the area of contact between Ectopleura sp. and A. subpinnata: on the outer side the black coral coenenchyme and spiny skeleton (bc), on the inner side the perisarc and the coenosarc of the hydroid (hy). M, black coral branchlet (bc) hosting Ectopleura sp. (hy). Cylindrical, pointed, irregularly arranged spines are visible near the attachment area of the hydrocaulus. Scale bars: A, 5 cm. D, 2 mm. B,C,E–H,K,M, 1 mm. J, 0.5 mm. L, 10 μm.

Figure 3. Scheme of the two associations. A, Ectopleura sp. on Antipathella subpinnata. B, Ectopleura sp. on Eunicella cavolinii. The distal portions of the hydrocauli have been represented as the coral tissue was removed to show the skeletons beneath.

Coward , WE. 1909 . On Ptilocodium repens a new gymnoblastic hydroid epizoic on a Pennatulid . Verslagen der Zittingen van de Wis-en Natuurkundige Afdeeling der Koninklijke Akademie van Wetenschappen, Amsterdam, Section of Sciences , 11 : 635 – 641 .

 Google Scholar

Stechow , E. 1909 . Beiträge zur Naturgeschichte Ostasiens: hydroid-polypen der japanischen Ostküste. Abhandlungen Kgl . Bayerischen Akademie der Wissenschaften , 1 : 1 – 111 .

 Google Scholar

Bouillon , J. 1967 . Révision de la famille des Ptilocodiidae avec la description d'un nouveau genre et d'une nouvelle espèce . Bulletin Académie royale de Belgique , 53 : 1106 – 1131 .

 Google Scholar

Hirohito Emperor Showa . 1988 . “ Athecata ” . In The hydroids of Sagami Bay , 1 – 179 . Tokyo : Biological Laboratory Imperial Household .

 Google Scholar

Puce , S , Di Camillo , CG and Bavestrello , G. 2008b . Hydroids symbiotic with octocorals from Sulawesi Sea, Indonesia . Journal of the Marine Biological Association of the United Kingdom , 88 : 1643 – 1654 .

 Web of Science ®Google Scholar

Gili , JM , Lopez-González , PJ and Bouillon , J. 2006 . A new Antarctic association: The case of the hydroid Sarsia medelae (new sp.) associated with gorgonians . Polar Biology , 29 : 624 – 631 .

 Web of Science ®Google Scholar

Watson , JE. 1980 . The identity of two tubularian hydroids from Australia with a description and observations on the reproduction of Ralpharia magnifica gen. et sp. nov . Memoirs of the National Museum of Victoria , 41 : 53 – 63 .

 Google Scholar

Watson , JE. 1984 . Two new species of tubularian hydroids from southern Australia . Memoirs of the National Museum of Victoria , 45 : 7 – 12 .

 Google Scholar

Petersen , KW. 1990 . Evolution and taxonomy in capitate hydroids and medusae . Zoological Journal of the Linnean Society , 100 : 101 – 231 .

 Web of Science ®Google Scholar

Silveira , FL da and Migotto , AE . 1984 . Serehyba sanctisebastiani n. gen., n. sp. (Hydrozoa, Tubulariidae), symbiont of a gorgonian octocoral from the southeast coast of Brazil . gBijdragen Tot De Dierkunde , 54 : 231 – 242 .

 Google Scholar

Korotneff , A. and de . 1887 . Zwei neue Coelenteraten . Zeitschrift fur Wissenschaftliche Zoologie , 45 : 468 – 490 .

 Google Scholar

Boero , F , Bouillon , J and Gravier-Bonnet , N. 1995 . The life cycle of Pteroclava krempfi (Cnidaria, Hydrozoa, Cladocorynidae), with notes on Asyncoryne philippina (Asyncorynidae) . Scientia Marina , 59 : 65 – 76 .

 Web of Science ®Google Scholar

Billard , A. 1919 . Note sur une espèce nouvelle d'hydroide gymnoblastique (Clava krempfi), parasite d'un Alcyonaire . Bulletin du muséum national d'Histoire naturelle, Paris , 25 : 187 – 188 .

 Google Scholar

Boero , F , Bouillon , J and Gravili , C. 2000 . A survey of Zanclea, Halocoryne and Zanclella (Cnidaria, Hydrozoa, Anthomedusae, Zancleidae) with a description of new species . Italian Journal of Zoology , 67 : 93 – 124 .

 Web of Science ®Google Scholar

Millard , NAH and Bouillon , J. 1973 . Hydroids from the Seychelles (Coelenterata) . Annales du Musée Royale de l'Afrique Centrale, Sciences Zoologiques , 206 : 1 – 106 .

 Google Scholar

Millard , NAH. 1975 . Monograph on the Hydroida of southern Africa . Annals of the South African Museum , 68 : 1 – 513 .

 Google Scholar

Pantos , O and Bythell , JC. 2010 . A novel reef coral symbiosis . Coral Reefs , 29 : 761 – 770 .

 Web of Science ®Google Scholar

Vertino , A , Savini , A , Rosso , A , Di Geronimo , I , Mastrototaro , F , Sanfilippo , R , Gay , G and Etiope , G. 2009 . Benthic habitat characterization and distribution from two representative sites of the deep-water SML Coral Mound Province (Mediterranean) . Deep Sea Research II , 57 : 380 – 396 .

 Web of Science ®Google Scholar