Zoantharians are a group of cnidarians that are often found in association with marine invertebrates, including corals, in shallow and deep-sea environments. However, little is known about deep-sea zoantharian taxonomy, specificity and nature of their associations with their coral hosts. In this study, analyses of molecular data (mtDNA COI, 16S, and 12S rDNA) coupled with ecological and morphological characteristics were used to examine zoantharian specimens associated with cold-water corals (CWC) at depths between 110 and 800 m from seamounts and island slopes in the Azores region. The zoantharians examined were found living in association with stylasterids, antipatharians and octocorals. From the collected specimens, four new species were identified: (1) Epizoanthus martinsae sp. n. associated with the antipatharian Leiopathes sp.; (2) Parazoanthus aliceae sp. n. associated with the stylasterid Errina dabneyi (Pourtalès, 1871); (3) Zibrowius alberti sp. n. associated with octocorals of the family Primnoidae [Paracalyptrophora josephinae (Lindström, 1877)] and the family Plexauridae (Dentomuricea aff. meteor Grasshoff, 1977); (4) Hurlizoanthus hirondelleae sp. n. associated with the primnoid octocoral Candidella imbricata (Johnson, 1862). In addition, based on newly collected material, morphological and molecular data and phylogenic reconstruction, the zoantharian Isozoanthus primnoidus Carreiro-Silva, Braga-Henriques, Sampaio, de Matos, Porteiro & Ocaña, 2011, associated with the primnoid octocoral Callogorgia verticillata (Pallas, 1766), was reclassified as Zibrowius primnoidus comb. nov. The zoantharians, Z. primnoidus comb. nov., Z. alberti sp. n., and H. hirondelleae sp. n. associated with octocorals showed evidence of a parasitic relationship, where the zoantharian progressively eliminates gorgonian tissue and uses the gorgonian axis for structure and support, and coral sclerites for protection. In contrast, the zoantharian P. aliceae sp. n. associated with the stylasterid E. dabneyi and the zoantharian E. martinsae sp. n. associated with the antipatharian Leiopathes sp., appear to use the coral host only as support with no visible damage to the host. The monophyly of octocoral-associated zoantharians suggests that substrate specificity is tightly linked to the evolution of zoantharians.
Keywords: antipatharians, gorgonians, molecular taxonomy, parasitic, phylogeny, stylasterids, Zoantharia
Systematics
Phylum Cnidaria Hatschek, 1888
Class Anthozoa Ehrenberg, 1831
Subclass Hexacorallia Haeckel, 1896
Order Zoantharia Gray, 1832
Suborder Macrocnemina Haddon and
Shackleton, 1891
Family Parazoanthidae Delage and
Hérouard, 1901
Genus Zibrowius Sinniger, Ocaña & Baco,
2013
Zibrowius primnoidus comb. nov.
Zibrowius alberti sp. n.
Etymology: This species name is dedicated to Prince Albert I
of Monaco for his promotion of the oceanographic sciences in
the late 19th to early 20th centuries, and for his oceanographic
campaigns in the Azores which contributed to the increased
knowledge of CWCs and associated fauna in the region.
Genus Hurlizoanthus Sinniger, Ocaña &
Baco, 2013
Hurlizoanthus hirondelleae sp. n.
Etymology
This species name is dedicated to the research yacht Hirondelle
used by Prince Albert I of Monaco during his oceanographic
campaigns in the Azores.
Genus Parazoanthus Haddon and
Shackleton, 1891
Parazoanthus aliceae sp.n.
Etymology
This species name is dedicated to another research yacht of Prince
Albert I of Monaco, Princess Alice, used during his oceanographic
campaigns in the Azores, and during which the homonymous
seamount was discovered.
Family Epizoanthidae Delage and
Hérouard, 1901
Genus Epizoanthus Gray, 1867
Epizoanthus martinsae sp. n.
Etymology The name of this species is dedicated to Dr. Helen Martins, researcher at the Department of Oceanography and Fisheries of the University of the Azores for her contribution to the advancement of marine science in the Azores through her research and dedication to the Azorean scientific journal Arquipélago.
Marina Carreiro-Silva, Oscar Ocaña, David Stanković, Íris Sampaio, Filipe M. Porteiro\, Marie-Claire Fabri and Sergio Stefanni. 2017. Zoantharians (Hexacorallia: Zoantharia) Associated with Cold-Water Corals in the Azores Region: New Species and Associations in the Deep Sea. Front. Mar. Sci. 4:88. DOI: 10.3389/fmars.2017.00088