Antipathozoanthus hickmani, Reimer & Fujii, 2010

Reimer, James & Fujii, Takuma, 2010, Four new species and one new genus of zoanthids (Cnidaria, Hexacorallia) from the Galapagos Islands, ZooKeys 42 (42), pp. 1-36 : 6-14

Antipathozoanthus hickmani sp. n.

urn:lsid:zoobank.org:act:BC6BFB57-105C-4EC4-AEF4-87CC8B33DBDE

Figures 1, 5, 7, 9, Tables 1, 2, 3

Etymology. Named after Dr. Cleveland Hickman, Jr., who graciously invited the first author to the Galápagos, and collected the first specimens of this new species. Noun in the genitive case.

Material examined. Type locality: Ecuador, Galapagos: Floreana I., La Batielle, 1.2904°S 90.4989°W.

Holotype: Specimen number MHNG-INVE-67495. Colony of approximately 40 polyps connected by well-developed coenenchyme on two branches of Antipathes galapagensis Diechmann, 1941 branches. Both branches approximately 7 cm long. Polyps approximately 1.5–4.0 mm in diameter, and approximately 1.0–6.0 mm in height from coenenchyme. Coenenchyme covers branches of antipatharian. Polyps and coenenchyme sand encrusted, cream-yellow in color. Collected from La Batielle, Floreana I., Galapagos, Ecuador, at 31.4 m by A. Chiriboga ( AC), March 13, 2007. Preserved in 99.5% ethanol.

Paratypes (all from Galapagos, Ecuador):

Paratype 1. Specimen number CMNH-ZG 05883. Collected from Roca Onan, Pinzon I., at 27 m by AC, March 14, 2007.

Figure ļ. Antipathozoanthus hickmani sp. n. in situ in the Galapagos. a holotype MHNG-INVE-67495 showing the entire colony covering an Antipathes galapagensis , with living antipatharians visible in the background. Image by Angel Chiriboga ( AC) b specimen MISE 441 at Don Ferdi, Bainbridge Rocks, Santiago I., at 23 m by JDR, March 9, 2007 c and d specimen MISE 474, Roca Onan. Pinzon I., at 35 m by AC. All scale bars: 1 cm except in a (10 cm).

Paratype 2. Specimen number USNM 1134064. Collected from Cousins Rock, at 28 m by James D. Reimer ( JDR), March 10, 2007.

Other material (all from Galapagos, Ecuador): MISE 03-221 , Cousins Rock , at 12 m by AC on October 9, 2003 ; MISE 03-539 , Cousins Rock , at 20 m by CH on November 11, 2003 ; MISE 03-549 , Cousins Rock , at 23 m by CH on November 11, 2003 ; MISE 04-341 , Elizabeth Bay , Isabela I., at 25 m by G. Edgar (GE) on December 2, 2003 ; MISE 440 , Don Ferdi , Bainbridge Rocks, at 22 m by JDR, March 9, 2007 ; MISE 441 , Don Ferdi , Bainbridge Rocks, at 23 m by JDR, March 9, 2007 ; MISE 444 , Cousins Rock , Galapagos, Ecuador, at 21 m JDR, March 10, 2007 ; MISE 474 , La Batielle , Floreana I., at 35 m by AC, March 14, 2007 .

Sequences. See Table 1.

Description. Size: Polyps in situ approximately 4–12 mm in diameter when open, and approximately 4–15 mm in height.

Morphology: Antipathozoanthus hickmani has approximately 40 bright yellow and/ or red tentacles, with long red, yellow, or cream-colored polyps that extend well clear of the coenenchyme (Figure 1). Tentacles are almost always longer than the expanded oral disk diameter.

Cnidae: Basitrichs and microbasic p-mastigophores (often difficult to distinguish), holotrichs (large and medium), spirocysts (see Table 2, Figure 9).

Differential diagnosis. Differs from Antipathozoanthus macaronesicus ( Ocaña & Brito, 2004) (with regards to distribution; Galapagos as opposed to Cape Verde), coloration (no red or cream colors observed in A. macaronesicus ), substrate ( Antipathes galapagensis as opposed to Tanacetipathes cavernicola Opresko, 2001 ).

Other morphologically similar and undescribed zoanthids (epizoic on antipatharians, similar sizes, yellowish in color) have been recorded from Madagascar and Japan (specimens in JDR’s collection), although these other specimens were found on different antipatharian species than Antipathozoanthus hickmani , and were never red or cream in color.

Antipathozoanthus hickmani is the only zoanthid in the Galápagos found on living Antipathes galapagensis ( Table 3).

Habitat and distribution. All collected samples from Galapagos were on the black coral Antipathes galapagensis , at depths of 12 m to 35 m. Although A. galapagensis is found throughout the archipelago, Antipathozoanthus hickmani colonies were observed only at Santiago, Floreana, Isabela and Pinzon Islands, and it may be that this genus has a patchy distribution in the Galápagos. A. hickmani is potentially also found at Isla del Coco ( Costa Rica) on the same antipatharian species, based on Museo de Zoologia, University of Costa Rica specimen UCR 827, although this has yet to be confirmed with detailed examinations.

Biology and associated species. Antipathozoanthus hickmani may cover only a portion of a living Antipathes galapagensis black coral colony, or cover the entire colony, suggesting this species may be parasitic. Some A. hickmani specimens were found on completely dead A. galapagensis colonies or branches.

Notes. Previously mentioned in Reimer et al. (2008b, 2010) and Hickman (2008) as Parazoanthus sp. G1.