Epizoanthus beriber, Kise, Hiroki & Reimer, James Davis, 2016

Kise, Hiroki & Reimer, James Davis, 2016, Unexpected diversity and a new species of Epizoanthus (Anthozoa, Hexacorallia) attached to eunicid worm tubes from the Pacific Ocean, ZooKeys 562, pp. 49-71 : 57-58

Taxon classification Animalia Zoantharia Epizoanthidae

Epizoanthus beriber sp. n.

Material examined.

Holotype. NSMT-Co1575 (MISE-HK129), 7°5'01.0"N, 134°15'80.0"E, Turtle Cove, Palau, depth 20 m, collected by Hiroki Kise, May 6, 2015, divided in two pieces, one portion fixed in 99.5% EtOH and the other in 5-10% saltwater formalin, deposited in National Museum of Nature and Science, Tokyo, Japan. Paratype 1. RMNH 42101 (MISE-HK126), 7°8'29.4"N, 134°13'23.3"E, Blue Hole, Palau, depth 36 m, collected by Hiroki Kise, May 5, 2015, divided in two pieces, one portion fixed in 99.5% EtOH and other in 5-10% saltwater formalin, deposited in Naturalis Biodiversity Center, Leiden, The Netherlands. Paratype 2. USNM 1296758, USNM 1296759 (MISE-HK113), 7°18'54.8"N, 134°13'13.3"E, Siaes Tunnel, Palau, depth 30 m, collected by Hiroki Kise, April 28, 2015, divided in two pieces, one portion fixed in 99.5% EtOH and other in 5-10% saltwater formalin, deposited in Smithsonian Institution National Museum of Natural History, Washington, D.C., USA. Other material. MISE-HK112, 7°18'54.8"N, 134°13'13.3"E, Siaes Tunnel, Palau, depth 37 m, collected by Hiroki Kise, April 28, 2015, divided in two pieces and fixed in 99.5% EtOH and 5-10% saltwater formalin, respectively; MISE-HK116, 7°18'54.8"N, 134°13'13.3"E, Siaes Tunnel, Palau, depth unknown, collected by Hiroki Kise, April 28, 2015, divided in two pieces and fixed in 99.5% EtOH and 5-10% saltwater formalin, respectively; MISE-HK117, 7°18'54.8"N, 134°13'13.3"E, Siaes Tunnel, Palau, depth unknown, collected by Hiroki Kise, April 28, 2015, fixed in 99.5% EtOH; MISE-HK118, 7°18'54.8"N, 134°13'13.3"E, Siaes Tunnel, Palau, depth unknown, collected by Hiroki Kise, April 28, 2015, fixed in 99.5% EtOH; MISE-HK119, 7°18'54.8"N, 134°13'13.3"E, Siaes Tunnel, Palau, depth 19 m, collected by Hiroki Kise, April 28, 2015, fixed in 99.5%; MISE-HK120, 7°18'54.8"N, 134°13'13.3"E, Siaes Tunnel, Palau, depth unknown, collected by Hiroki Kise, April 28, 2015, fixed in 99.5% EtOH; MISE-HK124, 8°19'00.0"N, 134°63'00.0"E, Negruangel, Palau, depth 27 m, collected by Hiroki Kise, April 29, 2015, fixed in 99.5% EtOH; MISE-HK125, 7°8'29.4"N, 134°13'23.3"E, Blue Hole, Palau, depth 32 m, collected by Hiroki Kise, May 5, 2015, divided in two pieces and fixed in 99.5% EtOH and 5-10% saltwater formalin, respectively; MISE-HK127 7°8'29.4"N, 134°13'23.3"E, Blue Hole, Palau, depth 36 m, collected by Hiroki Kise, May 5, 2015, fixed in 99.5% EtOH; HK128 7 °8'12.3"N, 134°13'16.5"E, Blue Corner, Palau, depth 29 m, collected by Hiroki Kise, May 5, 2015, fixed in 99.5% EtOH.

Description of holotype.

Colony of approximately 75 polyps connected by moderately developed coenenchyme on eunicid worm tubes. Polyps were attached to from base to proximal extremity of zig-zag shaped tubes of eunicid worms, and attached to not only bent sections but also to other locations. Polyps approximately 1.4 to 1.9 mm high from coenenchyme, and 0.7-1.0 mm in diameter. Azooxanthellate. Polyp external coloration is white, oral disk solid in color, ranging from light brown to brown (Figure 4d). Tentacles are transparent and approximately 20-22 in number.

Diagnosis.

Morphology. Polyps connected by moderately developed coenenchyme on eunicid worm tubes belonging to the genus Eunice , as are Epizoanthus illoricatus and Epizoanthus inazuma sp. n. Polyps are either circular cones or cylindrical, and approximately 0.5 to 2.1 mm high from coenenchyme (=length) and 1.1 to 2.1 mm diameter (in 5-10% seawater formalin). Maximum diameter of polyps is approximately 3 mm, maximum height approximately 5 mm in situ. Polyps have 20-22 tentacles that are longer than oral disk diameter. In addition, polyp external color is white while oral disk is light brown to brown.

Internal anatomy. Mesogleal thickness approximately 80 µm. We could not obtain cross-sections or images to observe mesentery arrangement due to heavy sand encrustation.

Cnidae. Holotrichs, basitrichs, microbasic p-mastigophores, spirocysts (see Table 1, Figure 3).

Etymology.

Epizoanthus beriber sp. n. is named after the legendary Beriber of Palauan folklore, who lived in a cave at Oikuul in Airai State, as this species has been found only in caves. Common Japanese name. ‘Ziguzagu-yadori-sunaginchaku’ (new Japanese name).

Distribution and habitat.

Epizoanthus beriber sp. n. is found only on the floor or sides of caves, and always in association with eunicid worm tubes (Figure 4d, e). Specimens were collected from 20-40 m in this study. Epizoanthus beriber sp. n. is known from Palau and Papua New Guinea (Figure 1). However, it may be distributed around the Pacific Ocean as we have speculated for Epizoanthus inazuma sp. n.

Remarks.

Epizoanthus beriber sp. n. can be distinguished from Epizoanthus illoricatus and Epizoanthus inazuma sp. n. by habitat and coloration. Epizoanthus beriber sp. n. was found only in caves while Epizoanthus inazuma sp. n. and Epizoanthus illoricatus were found on reef slopes or flat reef floors. Epizoanthus beriber sp. n. has white colonial polyps with a moderately developed coenenchyme (Figure 4d, e) while Epizoanthus inazuma sp. n. has black colonial polyps with a well-developed coenenchyme and Epizoanthus illoricatus has gray, yellow or black colonial polyps with a either poorly developed or well-developed coenenchyme (Figure 4 a–c, f).

The holotype of Epizoanthus illoricatus was presumably collected by dredging or net as there was no SCUBA in the 1930s; and it can be inferred that the holotype of Epizoanthus illoricatus lived in a location where it could be collected by such a method, such as on a reef flat or reef slope. Epizoanthus inazuma sp. n. is also found in such areas. However, Epizoanthus beriber sp. n. is only known from underwater caves that cannot be easily accessed from the surface.