Epizoanthus illoricatus Tischbierek, 1930

Reimer, James D., Poliseno, Angelo & Hoeksema, Bert W., 2014, Shallow-water zoantharians (Cnidaria, Hexacorallia) from the Central Indo-Pacific, ZooKeys 444, pp. 1-57 : 19

Taxon classification Animalia Zoantharia Epizoanthidae

23. Epizoanthus illoricatus Tischbierek, 1930 Figures 20A, 21

Specimens examined

(n=4). RMNH Coel 40533, Snellius–II Expedition Station 4.222, south of Pulau Tarupa Kecil, Taka Bone Rate (06°31'30"S, 121°08'00"E), depth 58 m, collected on October 15, 1984 by rectangular dredge; RMNH Coel 40546, Snellius–II Expedition Station 4.051, east of Melolo, northeast Sumba (09°53'30"S, 120°42'42"E), depth = 75 to 90 m, collected on September 13, 1984 by rectangular dredge; RMNH Coel 40571, Ternate Expedition Station TER.27, Tanjung Ratemu, south of river, west Halmahera Sea (00°54'44"N, 127°29'10"E), depth = 20 m, collected on November 08, 2007 by B.W. Hoeksema; RMNH Coel 40758, station LEM.32, north Sarena Kecil, Lembeh Strait, North Sulawesi (01°27'26"N, 125°13'38"E), depth = 30 m, collected on February 16, 2012 by B.W. Hoeksema.

Photographic records

(n=6). West Menjangan, West Bali (08°05'33"S, 114°29'47"E) May 22, 1998 (3 different specimens); Maluku Expedition station MAL.21, north coast Ambon Bay, Tanjung Hatupero, east of Lilibooi, Ambon (03°44'S, 128°02'E), November 20, 1996; southeast Likuan, Bunaken, North Sulawesi (01°36'N, 124°47'E), May 10, 1998; station BER.04, south Pulau Derawan, East Kalimantan (02°17'03"N, 118°14'49"E), October 18, 2003.

Description.

Originally described from the Philippines. Azooxanthellate. Polyps of this species often grow at the outer bends of the zig-zag shaped tubes, and combined with polyps’ smaller size and thin coenenchyme (Figure 20A), colonies appear to be much less crowded than as seen in Epizoanthus aff. illoricatus (Figure 20B).

Polyps of specimens in the RMNH collection are generally less than 1 mm in diameter, and never more than 2 mm, and of approximately equal height. Coenenchyme generally light gray in color, oral disk and tentacles semi-translucent brown. Tentacles in images 20-22 in number, much thinner than as seen in Epizoanthus aff. illoricatus below, with orange or white colored proximal tips, longer in length than oral disk diameter. The two deeper specimens (RMNH Coel 40533 and 40546) have highly developed thin coenenchymes covering the entire worm tubes’ surface, and are both dark black in color. On the other hand, the shallower specimens had some unitary polyps, and colonial polyps were often in clusters of two or three with poorly developed coenenchyme.

The morphological characters and dimensions observed in the specimens in this study agree well with the original description by Tischbierek (1930).

Distribution.

Regions recorded in this study (Figure 21). West Bali (4), northeast Sumba (6), Take Bone Rate (11), Moluccas (14), west Halmahera Sea (16), Lembeh Strait (17), Bunaken (18), Berau Islands (19).

Past records. Originally described from Manila, and subsequently reported from Taiwan ( Reimer et al. 2013a), New Caledonia ( Sinniger 2006), Palau ( Reimer et al. 2014a), and Osprey Reef, Australia in the Coral Sea ( Lindsay et al. 2012), indicating a western Indo-Pacific distribution. Found from specimens in this study as shallow as 20 m, and as deep as 90 m, similar to depths reported at Osprey Reef (=82.5 m) ( Lindsay et al. 2012).

Remarks.

Until this report, any Epizoanthus spp. on a zig-zag shaped eunicid worm was recorded as Epizoanthus illoricatus . However, from the preliminary analyses here, it appears that there may be two or more species within this group. Thus, previous records must be treated with caution.