Epizoanthus, CARLGREN, 1923, 1867

Kise, Hiroki, Montenegro, Javier, Santos, Maria E. A., Hoeksema, Bert W., Ekins, Merrick, Ise, Yuji, Higashiji, Takuo, Fernandez-Silva, Iria & Reimer, James D., 2022, Evolution and phylogeny of glass-sponge-associated zoantharians, with a description of two new genera and three new species, Zoological Journal of the Linnean Society 194, pp. 323-347 : 332-333

EPIZOANTHUS AFF. ARMATUS CARLGREN, 1923

( FIG. 3E )

Material examined: MISE-HPD1323 (NSMT-Co 1759), Kuroshima Island , Kagoshima, Japan, 24°13 ′ 36.1 ″ N, 124°06 ′ 18.0 ″E, depth 468 m, ROV, coll. J. D. Reimer on RV Natsushima, 19 Sep 2011, fixed in 90% ethanol .

Description: External morphology. Circa 80 cylindrical polyps connected by strongly developed light-brownish coenenchyme on stalks of hexactinellid sponges ( Hyalonema sp. ) in preserved specimen. Colony covered the upper part of the stalks, but not around the spiculous anchor. Contracted preserved polyps well developed and 0.5–4.9 mm in height, 2.5–7.8 mm in diameter.Capitulary ridges present but weakly pronounced when contracted, c. 14–16 in number. The numbers of tentacles of each polyp c. 28–32 and tentacles arranged in two rows.

Internal morphology. Zooxanthellae absent. Number of mesenteries 28–32, in macrocnemic arrangement. Reticulate mesogleal musculature.

Habitat and distribution: Off Kuroshima , Okinawa, in the Ryukyu Archipelago, Japan at a depth of 468 m. Epizoanthus armatus has previously been reported from off Somalia in the Indian Ocean ( Carlgren, 1923).

Associated host: Hyalonema sp.

Remarks: Polyp dimensions of the examined specimen are larger than those of E. fatuus and E. stellaris , and this specimen resembles E. armatus as described by Carlgren (1923). The morphological characters and dimensions observed in the examined specimen agree well with the original description by Carlgren (1923). Epizoanthus armatus was originally described from East Africa ( Carlgren, 1923). Kise et al. (2018) reported the existence of E. planus Carlgren, 1923 in Japanese waters, and this species was also originally described from East Africa.Therefore, it is possible that E. armatus may also be distributed in Japanese waters. However, the collected depths of the examined specimen in this study and the specimens Carlgren (1923) examined are different (468 m vs. 741–1362 m deep). We also could not observe internal morphology of the examined specimen due to its poor preserved condition. Therefore, we here preliminarily identified the examined specimen as Epizoanthus aff. armatus . Examination of additional specimens combined with molecular analyses should help confirm the identity of this specimen.

Figures

Figure 3. Images of preserved Amphidiscophora spongesassociated zoantharians. A, B, Epizoanthus fatuus collected from Japan; C, Epizoanthus aff. fatuus collected from Australia; D, Epizoanthus stellaris collected from Australia; E, Epizoanthus aff. armatus collected from Japan. Scales: 10 mm.