Antipathozoanthus cavernus, Kise, Hiroki, Fujii, Takuma, Masucci, Giovanni Diego, Biondi, Piera & Reimer, James Davis, 2017

Kise, Hiroki, Fujii, Takuma, Masucci, Giovanni Diego, Biondi, Piera & Reimer, James Davis, 2017, Three new species and the molecular phylogeny of Antipathozoanthus from the Indo-Pacific Ocean (Anthozoa, Hexacorallia, Zoantharia), ZooKeys 725, pp. 97-122 : 105-106

Antipathozoanthus cavernus sp. n. Fig. 2d

Material examined.

Holotype: NSMT-Co1604 (MISE-KINKO1), colony of approximately 125 polyps connected by a highly developed coenenchyme on genus Myripathes ( Antipatharia : Myriopathidae ). Preserved polyps approximately 2.0-5.0 mm in diameter, and approximately 2.0-5.0 mm in height from coenenchyme. Collected from Sakurajima, Kagoshima, Japan (31°35'23.5"N, 130.35.27.8"E) at a depth of 21 m by JDR, 20 September 2015.

Paratypes: RUMF-ZG-4401 (MISE-MAL2592601), collected from Capital Reef, Maldives (3°02'55.8"N, 72°53'21.2"E) at a depth of 19 m by Marco Oliverio, 16 May 2014; RMNH.Coel.42322 (MISE-PALAU5), collected from Siaes Tunnel, Palau (7°18'54.8"N, 134°13'13.3"E) at a depth of 39 m by JDR, 15 September 2014.

Diagnosis.

External morphology: Polyps in situ are approximately 4-15 mm in diameter when oral disk is expanded, and approximately 3-10 mm in height (Fig. 2). Colonial zoantharian with polyps connected by highly developed coenenchyme on Myripathes . Antipathozoanthus cavernus sp. n. has approximately 32-40 translucent tentacles of approximately 1 to 5 mm in length. Tentacle lengths are either as long as or slightly shorter than expanded oral disk diameter. Polyps have orange oral disk with orange or light orange ring around oral disk. When polyps are closed, capitular ridges are present and observed clearly, numbering approximately 16-20. The capitulum is orange or light orange in color. Polyps encrusted with visible sand particles (1-8 mm) in their coenenchyme and ectodermal tissue. Polyps usually much more encrusted than coenenchyme. Colonies attached on axis from proximal extremity to base of Myripathes .

Internal morphology: Cteniform endodermal arrangement marginal muscle sensu Swain et al. (2015) in longitudinal section (Fig. 4). Azooxanthellate. Large scattered lacunae in ectoderm and mesogleal are present due to their encrustations.

Cnidae: Holotrichs (large and medium), basitrichs and microbasic p-mastigophores (usually difficult to distinguish from each other), spirocysts (Fig. 3; Table 2).

Habitat and distribution.

Antipathozoanthus cavernus sp. n. is found on the sides and/or floor of cave entrances, and on steep slopes, and always on Myripathes . Specimens were collected from depths of 19 to 39 m.

Differential diagnosis.

Antipathozoanthus cavernus sp. n. occurs in similar environments as A. remengesaui sp. n., but these species can be distinguished by their coenenchyme development and by the generic identity of the antipatharian host. A. remengesaui sp. n. is associated with genus Antipathes (family Antipathidae ) covered by a poorly developed coenenchyme, while A. cavernus sp. n. is associated with genus Myripathes (family Myripathidae ) covered by a highly developed coenenchyme. A. cavernus sp. n. can be distinguished from A. hickmani by a different coloration and by its antipatharian association; A. cavernus sp. n. does not have red or cream colored polyps as seen in A. hickmani . Additionally, A. hickmani is associated with Antipathes galapagensis , while A. cavernus sp. n. is associated with genus Myripathes . A. macaronesicus is easily distinguishable from A. cavernus sp. n. by their polyp coloration (orange and light orange versus pinkish and yellowish, and their antipatharian host (genus Antipathes versus genus Myripathes ). Finally, all species above have unique ITS-rDNA sequences.

Etymology.

Antipathozoanthus cavernus sp. n. is named from the Latin "caverna" meaning "cave", as this species is found in caves.

Common name.

Hana-tsuno-sunaginchaku (new Japanese name).