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We present the complete genome sequences of 13 species of the zoantharian suborder Brachycnemina (Haddon, and Shackleton, 1891; Poliseno et al., 2020). Genome sequencing was performed on genetic material from single wild-collected individuals. For each species the sequence reads were assembled using a de novo method followed by a finishing step. The raw and assembled data are publicly available via GenBank.

VITRUMANTHUS VANDERLANDI SP. NOV. (FIG. 7A–F) Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org:act: CE659473-CB9F-462B-97F7-4B974FAE96B9. Material examined: Holotype: RMNH.COEL.42623, CANCAP-VII Expedition Station CV 7.041, Cape Verde Islands, SãoTiago, Ilheus Rombos, east of Cima, 14°56 ′ 59 ″ N, 24°37 ′ 59 ″ W, Agassiz trawl, at a depth of 700–800 m, coll. RV HNIMS Tydeman, 24 Aug 1986, fixed in 99.5% ethanol. Paratype: RMNH.COEL.42624, CANCAP-VII Expedition Station CV 7.041, Cape Verde Islands, SãoTiago, Ilheus Rombos, east of Cima, 14°56 ′ 59 ″ N, 24°37 ′ 59 ″ W, Agassiz trawl, at a depth of 580 m depth, coll. RV HNIMS Tydeman, 24 Aug 1986. Other material examined: RMNH.COEL.42625, Equalant II Expedition to the Gulf of Guinea, as part of the ICITA Programme (International Cooperative Investigations of the Tropical Atlantic), Sta. 18/8, 38 km off Liberia, 4°25 ′ N, 8°29 ′ W, trawl at a depth range of 380–510 m, on RV Geronimo Cruise 2, 31 Oct 1963, fixed in 99.5% ethanol. Etymology: This species is named in honour of Dr Jacob van der Land, expedition leader of the CANCAP-VII expedition off the coast of West Africa (Van der Land, 1987), during which the type specimens of this species were collected. The Japanese name is 'Hime-ruri-sunaginchaku'. Description: External morphology. Thirty-two cylindrical polyps in preserved specimen. Base of polyps embedded in Aphrocallistes sponge. Solitary polyps arise irregularly from host hexactinellid sponge. Preserved polyps cream white in coloration. Surface of column smooth, and ectoderm continuous. Ectoderm of polyps partially encrusted with small size of sand and silica particles. Transparent capitulum contracted and rounded. Contracted preserved polyps 0.3–2.5 mm in height, 0.8–3.0 mm in diameter. Capitulary ridges indiscernible when contracted. Approximately 20 tentacles in number. Internal morphology. Zooxanthellae absent. Cyclically transitional marginal musculature. Mesoglea thickness 0.2–1.1 mm. Mesoglea thicker than ectoderm and endoderm. Siphonoglyph distinct and V-shaped. Mesenterial filaments present. Cnidae. Basitrichs and microbasic b-mastigophores, microbasic p-mastigophores and spirocysts (Fig. 5C; Table 2). Distribution and habitats: West Africa: Guinea and Cape Verde at depths of 580– 800 m. Associated host: Aphrocallistes beatrix Gray, 1858, Aphrocallistes sp. Remarks: Vitrumanthus vanderlandi is phylogenetically close to V. oligomyarius, but these two species can be distinguished by dimensions of polyps and the numbers of tentacles. Vitrumanthus vanderlandi and V. oligomyaria are also associated with different host hexactinellid sponges (Aphrocallistes species vs. Tretochone duplicata). Moreover, V. vanderlandi does not have any holotrich nematocysts in all tissues we examined, while other species of Vitrumanthus have holotrich nematocysts present in some tissues. Although the in situ polyp colour of V. vanderlandi is unknown, Buhl-Mortensen et al. (2017) have reported yellowed zoantharians that were observed on A. beatrix collected from the Gulf of Guinea. Therefore, the coloration of polyps of this species may be yellow. Further investigations with newly collected specimens are needed to confirm the in situ morphology of V. vanderlandi.

CHURABANA KUROSHIOAE SP. NOV. (FIG. 4A���I) Synonymy: Parazoanthidae sp. 1 ��� Reimer et al., 2019: 7, fig. 2A. Zoobank registration: u r n: l s i d: z o o b a n k. org:act: FC503255-BDC2-45C5-9788-41F52BC40FA5. Material examined: Holotype: RUMF-ZG-04447, near Iejima Island, Motobu, Okinawa, Japan, 26��54 ��� 53.6 ��� N, 127��37 ��� 50.9 ��� E, 600���650 m, baskets, coll. T. Higashiji on vessel Daini-kuroshio-maru, 2 March 2018, divided into two pieces, one portion fixed in 5���10% saltwater formalin and other in 99.5% ethanol. Paratype: RUMF-ZG-04448, near Iejima Island, Motobu, Okinawa, Japan, 26��54���53.6 ��� N, 127��37 ��� 50.9 ��� E, 600���650 m, baskets, coll. T. Higashiji on vessel Dainikuroshio-maru, 2 March 2018, fixed in 99.5% ethanol. MISE-JMG51J (NSMT-Co 1754), Nanpo Trough, Kikaijima Island, Kagoshima, Japan, 28��20 ��� 21.64 ��� N, 129��57 ��� 14.56 ��� E, depth 520 m, ROV, coll. Javier Montenegro on RV Natsushima, 14 Oct 2011, fixed in 99.5% ethanol. Etymology: The species is named after the Dainik u r o s h i o -m a r u, a s t h e t y p e s p e c i m e n s w e r e collected by this vessel. The Japanese name is 'Beni-chura-tama-sunaginchaku'. Description: External morphology. Four truncated cone-shaped or cylindrical polyps in preserved specimen. The polyp bases embedded within the sponge Pararete Ijima, 1927. Solitary polyps arise irregularly from Pararete specimens. The living polyps cream-pink or beige and tentacles cream or whitish transparent in coloration. Preserved polyps beige and partially red. Surface of column rough and ectoderm continuous. Ectoderm and mesoglea of polyps encrusted with numerous and various sizes of sand and silica particles. The living expanded oral disks c. 1.5��� 2.0 mm in diameter, expanded polyps c. up to 10 mm in height, 4.0���5.0 mm in diameter. Preserved contracted preserved polyps 3.0���4.0 mm in height, 2.8���4.0 mm in diameter. Capitulary ridges discernible, 15���16 in number when contracted. 30���32 tentacles in number. Internal morphology. Zooxanthellae absent. Cteniform endodermal marginal musculature. Encircling sinus present and basal canals of mesenteries absent. Mesenteries thin, 30���32 in macrocnemic arrangement. Mesoglea thickness 0.5���1.6 mm. Mesoglea thicker than ectoderm and endoderm. Siphonoglyph distinct and U-shaped. Mesenterial filaments present. Cnidae. Basitrichs and microbasic b-mastigophores, microbasic p-mastigophores, holotrichs and spirocysts (Fig. 5A; Table 2). Distribution and habitats: Ryukyu Archipelago, Japan: Near Iejima Island, Okinawa and Nanpo Trough, Kikaijima Island, Kagoshima, Japan at depths of 520��� 650 m. Associated host: Pararete sp. 1 and Pararete sp. 2. R e m a r k s: C h u r a b a n a k u r o s h i o a e r e s e m b l e s Vitrumanthus species, but they can be easily separated by differences in their marginal musculatures (see also Remarks under Vitrumanthus)., Published as part of 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, pp. 323-347 in Zoological Journal of the Linnean Society 194 on pages 333-336, DOI: 10.1093/zoolinnean/zlab068, http://zenodo.org/record/5799592, {"references":["Reimer JD, Kise H, Santos MEA, Lindsay DJ, Pyle RL, Copus JM, Bowen BW, Nonaka M, Higashiji T, Benayahu Y. 2019. Exploring the biodiversity of understudied benthic taxa at mesophotic and deeper depths: examples from the order Zoantharia (Anthozoa: Hexacorallia). Frontiers in Marine Science 6: 305.","Ijima I. 1927. Hexactinellida of the Siboga expedition. In: Weber M, ed. Uitkomsten op zoologisch, botanisch, oceanographisch en geologisch gebied verzameld in Nederlandsch Oost-Indie 1899 - 1900, 6. Leiden: Brill, 1 - 138."]}

GENUS KAULUZOANTHUS SINNIGER ET AL., 2013 Type species: Kauluzoanthus kerbyi Sinniger et al., 2013 Diagnosis: Polyps do not contract when fixed. Characteristic insertion/deletion pattern in the 16S V5 region sensu Sinniger et al. (2005) (Sinniger et al., 2013)., Published as part of 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, pp. 323-347 in Zoological Journal of the Linnean Society 194 on page 341, DOI: 10.1093/zoolinnean/zlab068, http://zenodo.org/record/5799592, {"references":["Sinniger F, Ocana OV, Baco AR. 2013. Diversity of zoanthids (Anthozoa: Hexacorallia) on Hawaiian seamounts: description of the Hawaiian gold coral and additional zoanthids. PLoS One 8: e 52607.","Sinniger F, Montoya-Burgos JI, Chevaldonne P, Pawlowski J. 2005. Phylogeny of the order Zoantharia (Anthozoa, Hexacorallia) based on the mitochondrial ribosomal genes. Marine Biology 147: 1121 - 1128."]}

KAULUZOANTHUS SP. (FIG. 9A���B) Material examined: USNM 1424050, French Frigate Shoals, Hawaii (23��56.649 ��� N, 166��02.187 ��� W), 1225 m, ROV, coll. RV Okeanos Explorer, NOAA on 28 February 2016, fixed in 99.5% EtOH. Description: Non-encrusted azooxanthellate zoantharians. The examined specimen associated with Hyalonema sp. Preserved polyps cylindrical and c. 1.8���9.6 mm in height, 3.9���6.7 mm in diameter, with brown column in coloration. Thin coenenchyme completely covering stalk of Hyalonema sp. Capitulary ridges discernible, 14���16 in number when contracted. Tentacles relatively short, as long as expanded oral disk diameter. Numbers of tentacles 28���32. Associated host: Hyalonema sp. Distribution and habitats: North Pacific Ocean: French Frigate Shoals, Hawaii, at a depth of 1225 m. Remarks: The genus Kauluzoanthus is known to associate with the gold coral Kulamanamana haumeaae and with several octocoral species (Sinniger et al., 2013). However, our examined specimen was associated with Hyalonema sponges, and was genetically close to Ka. kerbyi based on the results in this study. This finding suggests that Kauluzoanthus species are not host-specific to Ku. haumeaae or other octocorals. However, we could not obtain any 16S-rDNA sequences, which contain the V5 region sensu Sinniger et al. (2005). Therefore, further integrated studies including morphological and ecological studies are needed to describe this putative new species., Published as part of 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, pp. 323-347 in Zoological Journal of the Linnean Society 194 on pages 341-342, DOI: 10.1093/zoolinnean/zlab068, http://zenodo.org/record/5799592, {"references":["Sinniger F, Ocana OV, Baco AR. 2013. Diversity of zoanthids (Anthozoa: Hexacorallia) on Hawaiian seamounts: description of the Hawaiian gold coral and additional zoanthids. PLoS One 8: e 52607.","Sinniger F, Montoya-Burgos JI, Chevaldonne P, Pawlowski J. 2005. Phylogeny of the order Zoantharia (Anthozoa, Hexacorallia) based on the mitochondrial ribosomal genes. Marine Biology 147: 1121 - 1128."]}

GENUS CHURABANA GEN. NOV. (FIG. 4A���H) Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org:act: EACFCC05-EA56-4F04-94A2-FB716F22004C. Type species: Churabana kuroshioae sp. nov. by original designation. Diagnosis: Parazoanthidae with obligate symbiotic relationship with massive hexasterophoran sponges. Preserved polyps 3.0���4.0 mm in height, 2.8���4.0 mm in diameter. Azooxanthellate. Cteniform endodermal marginal musculature. Remarks: Churabana and other already described sponge-associated zoantharian genera can be easily distinguished from each other by their host sponges (Hexactinellida sponges vs. Demospongiae sponge) and depths; the former can be found at> 140 m, while the latter are found in shallow coral reefs. Although Churabana and several species within Isozoanthus and Epizoanthus are associated with Hexactinellida sponges, these three genera can be distinguished from each other by their hosts: the latter two genera are associated with species within the subclass Amphidiscophora, while species of Churabana are associated with sponge species within the subclass Hexasterophora. Churabana has a unique deletion of 15 bp (from position 168 to 182 in our alignment) in its 16S-rDNA region. Etymology: The generic name is derived from the Ryukyuan language words chura, beautiful, and bana, flower, referring to the appearance of this species. Gender feminine. The Japanese name is 'Chura-tama-sunaginchaku'., Published as part of 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, pp. 323-347 in Zoological Journal of the Linnean Society 194 on page 333, DOI: 10.1093/zoolinnean/zlab068, http://zenodo.org/record/5799592

EPIZOANTHUS STELLARIS HERTWIG, 1888 (FIG. 3D) Material examined: QM G337585. Hunter CMR, New South Wales, Australia, 32��28 ��� 44.4 ��� S ���32��30 ��� 25.2 ��� S, 152��59 ��� 27.6 ��� E ���52��59 ��� 38.4 ��� E, depth 1006���1036 m, beam trawl, coll. M. Ekins on RV Investigator, Cruise IN2017_V03, 3 June 2017, fixed in 99.5% EtOH. Description: External morphology. Circa 40 nearly saucer-shaped polyps connected by strongly developed dark-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 only rise a little from the coenenchyme and flat, 0.4���1.1 mm in height, 3.0��� 6.9 mm in diameter. Capitulary ridges present and well pronounced when contracted, approximately 14���18 in number. Ectoderm and mesoglea of polyps and coenenchyme heavily encrusted with numerous sand and silica particles. Internal morphology. Zooxanthellae absent. Number of mesenteries 28���36, in macrocnemic arrangement. Mesogleal thickness c. 0.1���0.3 mm. Numerous and various size of pigment cells in the ectoderm and mesoglea. Mesoglea thicker than ectoderm and endoderm in column, actinopharynx and mesenteries. Reticulate mesogleal musculature short and poorly developed. Siphonoglyph distinct and V-shaped. Mesenterial filaments present. Habitat and distribution: Tasman Sea at depths of 1006���1036 m in this study. The type locality of this species is off Samboangan [Zamboanga City], Philippines at a depth of 150 m (82 fathoms). This species has been recorded from the Indian Ocean (Reimer & Sinniger, 2021), New Zealand (NIWA, 2018), the East Pacific Ocean (Beaulieu, 2001; Reimer & Sinniger, 2021) and the Caribbean Sea (Due��as & Puentes, 2018). Associated host: Hyalonema sp. Remarks: Epizoanthus stellaris can be distinguished from other Epizoanthus species found on stalks of hexactinellid sponges: the strongly lamellated polyps of E. stellaris are not observed in E. fatuus, E. armatus or E. longiceps (Lwowsky, 1913) (2.0���10.0 mm in height: Lwowsky, 1913; Carlgren, 1923). Lwowsky (1913) synonymized E. stellaris as E. fatuus on account of extreme growth forms of E. fatuus due to the high amounts of morphological variability that are commonly found within zoantharian species. However, the results of our molecular phylogenetic analyses support that E. stellaris and E. fatuus are distinct species. Beaulieu (2001) observed E. stellaris frequently in the East Pacific Ocean, although it should be noted that several species may be contained in E. stellaris, as observed by Beaulieu (2001), based on the results of the present study., Published as part of 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, pp. 323-347 in Zoological Journal of the Linnean Society 194 on page 331, DOI: 10.1093/zoolinnean/zlab068, http://zenodo.org/record/5799592, {"references":["Hertwig R. 1888. Report on the Actiniaria dredged by H. M. S, ' Challenger' during years 1873 - 1876. Supplement. In: Thomson CW, Murray J, eds. Report on the scientific results of the voyage of H. M. S. Challenger during the years 1873 - 76. Zoology 26: 39 - 41.","Reimer J, Sinniger F. 2021. World List of Zoantharia. Zoantharia. Available at: World Register of Marine Species: http: // marinespecies. org / aphia. php? p = taxdetails & id = 607338 (accessed on 2020 - 10 - 01) ..","NIWA. 2018. NIWA Invertebrate collection, v. 1.1. The National Institute of Water and Atmospheric Research (NIWA). Dataset / Occurrence. https: // nzobisipt. niwa. co. nz / resource? r = obisspecify & v = 1.1 (accessed on 2020 - 09 - 15).","Beaulieu SE. 2001. Life on glass houses: sponge stalk communities in the deep sea. Marine Biology 138: 803 - 817.","Duenas LF, Puentes V. 2018. Aportes al conocimiento de la biodiversidad de aguas profundas del mar Caribe colombiano. Anadarko Colombia Company. Bogota, Colombia. Occurrence dataset https: // doi. org / 10.15472 / kr 6 lqa accessed via GBIF. org (accessed on 2020 - 10 - 01).","Lwowsky FF. 1913. Revision der gattung Sidisia (Epizoanthus auct.), ein beitrag zur kenntnis der zoanthiden. Zoologische Jahrbucher (Systematik) 34: 557 - 613.","Carlgren O. 1923. Ceriantharia und zoantharia der deutschen tiefsee-expedition. Zoantharia. Wissenschaftliche Ergebnisse der Deutschen Tiefsee-Expedition auf dem Dampfer ' Valdivia' 1898 - 1899 19: 252 - 337."]}

GENUS VITRUMANTHUS GEN. NOV. (FIGS 6–8) Type species: Vitrumanthus schrieri sp. nov. by original designation. Zoobank registration: urn:lsid:zoobank.org:act: 00F773E4-4535-49F4-8CDA-30F569190BEF. Diagnosis: Parazoanthidae with obligate symbiotic r e l a t i o n s h i p w i t h m a s s i v e h e x a s t e r o p h o r a n a n d D e m o s p o n g i a e s p o n g e s. P r e s e r v e d p o l y p s 0.3–3.1 mm in length, 0.8–3.4 mm in diameter. Azooxanthellate. Cyclically transitional marginal musculature. Remarks: Vitrumanthus is distinguished from genus Churabana by its marginal musculature. In Vitrumanthus, cyclically transitional marginal musculature with several mesogleal lacunae was observed, while in Churabana cteniform endodermal marginal musculature with comb-like mesogleal pleats was seen. Molecular phylogenetic analyses clearly support the distinctiveness between Churabana and Vitrumanthus. In the 16S-rDNA region, Vitrumanthus has a unique deletion of 15 bp (positions 136–150 in our alignment). Etymology: The generic name is derived from the Latin word vitruma, glass, and Greek word anthos, flower, referring to the appearance of this genus. Gender masculine. The Japanese name is 'Ruri-sunaginchaku'.

EPIZOANTHUS FATUUS (SCHULTZE, 1860) (FIG. 3A, B) Synonymy: Palythoa fatua Schultze, 1860: 36, taf. 2, figs 1���2; Palythoa fatua ��� Andres, 1884: 311; Sidisia fatua ��� Lwowsky, 1913: 589���596, taf. 19, figs 5���8; Sidisia fatua var. alba ��� Lwowsky, 1913: 597. Material examined: MISE-HK33-2 (NSMT-Co 1757), off Amakusa, Kumamoto, Japan, 32��24 ��� 44.8 ��� N 129��28 ��� 01.3 ��� E (position approximate, exact location unknown), 1000 m depth, beat trawl, coll. D. Uyeno on the training vessel Nagasaki-maru, 2011, fixed in 99.5% ethanol. MISE-HK132 (NSMT-Co 1758), Sagami Bay, Kanagawa, Japan, 35��08 ��� 27.5 ��� N ���35��0 8 ��� 33.5 ��� N, 139��32 ��� 12.2 ��� E ���139��32 ��� 44.3 ��� E, 133���274 m depth, dredging, coll. H. Kotsuka on vessel Rinkaimaru, 12 Feb 2015, fixed in 99.5% ethanol. Description: External morphology. Ten to 50 cylindrical polyps connected by strongly developed dark brown and light beige coenenchyme on stalks of hexactinellid sponges (Hyalonema sp.) in preserved specimens. Column of preserved polyps dark brown and light beige in coloration. Colonies covered upper part of stalks, but not around the spiculous anchor. Contracted preserved polyps 0.8���2.9 mm in height, 1.9���3.6 mm in diameter. Capitulum swollen, and diameter of capitulum larger than scapus when contracted. Capitulary ridges present and strongly pronounced when contracted, 14 in number. The number of tentacles of each polyp in this study 28, and tentacles arranged in two rows. Ectoderm and mesoglea of polyps and coenenchyme heavily encrusted with numerous sand and silica particles. Internal morphology: Zooxanthellae absent. Number of mesenteries 28, in macrocnemic arrangement. Mesogleal thickness 0.1���0.3 mm and gradually wider in direction from capitulum towards scapus. Mesoglea either as thick as or thinner than ectoderm. Reticulate mesogleal musculature. Siphonoglyph distinct and V-shaped. Mesenterial filaments present. Habitat and distribution: Indo-Pacific Ocean: near Indonesia (Carlgren, 1923), East China Sea (Pei 1998), the Bay of Bengal, India and Japan (Lwowsky, 1913). Associated host. Hyalonema spp. Remarks: This species has been reported in several studies, which indicate the presence of intraspecific variation (Andres, 1884; Lwowsky, 1913, Carlgren, 1923). In fact, we observed several morphological differences, such as coloration and polyp dimensions, between the two examined specimens (NSMT-Co 1757 and NSMT-Co 1758). Also, some genetic variation of E. fatuus was observed in ITS-rDNA sequences (8 bp), and thus the possibility remains that E. fatuus contains cryptic species, as ITS-rDNA has been demonstrated to be among the most variable genetic regions currently utilized to delineate species within Zoantharia (e.g. Reimer et al., 2007; Montenegro et al., 2015). However, the sequences of the two examined specimens formed a strongly supported monophyletic clade and we therefore identify the examined specimens as a single species in this study. Additional specimens and fine-scale genetic analyses are required to better examine if there is any cryptic diversity within this group., Published as part of 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, pp. 323-347 in Zoological Journal of the Linnean Society 194 on pages 327-330, DOI: 10.1093/zoolinnean/zlab068, http://zenodo.org/record/5799592, {"references":["Schultze MJS. 1860. Die Hyalonemen. Ein Beitrag zur Naturgeschichte der Spongien. Bonn: A. Marcus, i - iii, 1 - 46.","Andres A. 1884. Le Attinie. Fauna und Flora des Golfes von Neapel 9: 1 - 459.","Lwowsky FF. 1913. Revision der gattung Sidisia (Epizoanthus auct.), ein beitrag zur kenntnis der zoanthiden. Zoologische Jahrbucher (Systematik) 34: 557 - 613.","Carlgren O. 1923. Ceriantharia und zoantharia der deutschen tiefsee-expedition. Zoantharia. Wissenschaftliche Ergebnisse der Deutschen Tiefsee-Expedition auf dem Dampfer ' Valdivia' 1898 - 1899 19: 252 - 337.","Pei Z. 1998. Fauna Sinica. Coelenterata: Actiniaria, Ceriantharia, Zoanthidea. Beijing: Science Press, 200 - 201.","Reimer JD, Takishita K, Ono S, Maruyama T. 2007. Diversity and evolution in the zoanthid genus Palythoa (Cnidaria: Hexacorallia) based on nuclear ITS-rDNA. Coral Reefs 26: 399 - 410.","Montenegro J, Sinniger F, Reimer JD. 2015. Unexpected diversity and new species in the sponge-Parazoanthidae association in southern Japan. Molecular Phylogenetics and Evolution 89: 73 - 90."]}

GENUS VITRUMANTHUS GEN. NOV. (FIGS 6���8) Type species: Vitrumanthus schrieri sp. nov. by original designation. Zoobank registration: urn:lsid:zoobank.org:act: 00F773E4-4535-49F4-8CDA-30F569190BEF. Diagnosis: Parazoanthidae with obligate symbiotic r e l a t i o n s h i p w i t h m a s s i v e h e x a s t e r o p h o r a n a n d D e m o s p o n g i a e s p o n g e s. P r e s e r v e d p o l y p s 0.3���3.1 mm in length, 0.8���3.4 mm in diameter. Azooxanthellate. Cyclically transitional marginal musculature. Remarks: Vitrumanthus is distinguished from genus Churabana by its marginal musculature. In Vitrumanthus, cyclically transitional marginal musculature with several mesogleal lacunae was observed, while in Churabana cteniform endodermal marginal musculature with comb-like mesogleal pleats was seen. Molecular phylogenetic analyses clearly support the distinctiveness between Churabana and Vitrumanthus. In the 16S-rDNA region, Vitrumanthus has a unique deletion of 15 bp (positions 136���150 in our alignment). Etymology: The generic name is derived from the Latin word vitruma, glass, and Greek word anthos, flower, referring to the appearance of this genus. Gender masculine. The Japanese name is 'Ruri-sunaginchaku'., Published as part of 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, pp. 323-347 in Zoological Journal of the Linnean Society 194 on page 336, DOI: 10.1093/zoolinnean/zlab068, http://zenodo.org/record/5799592

VITRUMANTHUS OLIGOMYARIUS (WASSILIEFF, 1908) COMB. NOV. (FIG. 8A���G) Basionym: Gemmaria oligomyaria Wassilieff, 1908: 47, fig. 29; taf. I, fig. 29. Material examined: CMNH ZG-4785, off Katsuura, Chiba, Japan, 34��50���N ���35��00���N, 140��20���W ���140��30���W, 390, vertical long line fishing, coll. A. Tamura on vessel Kiyo-maru, 19 Jan 2006, divided into two pieces, one portion fixed in 5���10% saltwater formalin and other in 99.5% ethanol. Description: External morphology. Circa> 300 cylindrical polyps. Solitary polyps arise from Tretochone duplicata (Topsent, 1928) in preserved specimen. Preserved polyps dark-yellow in coloration and trapezoid when opened. Polyps located all over the three-dimensional structured hexactinellid sponge body. Surface of column smooth, and ectoderm continuous. Ectoderm of polyps partially encrusted with small sized sand and silica particles (c., Published as part of 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, pp. 323-347 in Zoological Journal of the Linnean Society 194 on page 341, DOI: 10.1093/zoolinnean/zlab068, http://zenodo.org/record/5799592, {"references":["Wassilieff A. 1908. Japanische actinien, in Doflein. Abhandlungen der Mathematisch-Physikalischen Klasse der Koniglich Bayerischen Akademie der Wissenschaften 1: 1 - 49.","Topsent E. 1928. Sur deux Euretides du Japon. (Note preliminaire). Bulletin de l'Institut oceanographique de Monaco 515: 1 - 4.","Haddon AC, Shackleton AM. 1891 b. Actiniae: I. Zoantheae. In: Reports on the zoological collections made in the Torres Straits by Professor A. C. Haddon, 1888 - 1889. Scientific Transactions of the Royal Dublin Society 4: 673 - 701, pls 61 - 64.","Sinniger F, Reimer JD, Pawlowski J. 2010. The Parazoanthidae (Hexacorallia: Zoantharia) DNA taxonomy: description of two new genera. Marine Biodiversity 40: 57 - 70.","Reimer J, Sinniger F. 2021. World List of Zoantharia. Zoantharia. Available at: World Register of Marine Species: http: // marinespecies. org / aphia. php? p = taxdetails & id = 607338 (accessed on 2020 - 10 - 01) .."]}

EPIZOANTHUS AFF. FATUUS (SCHULTZE, 1860) (FIG. 3C) Material examined: QM G337590. Hunter CMR, Australia, New South Wales, 32��34 ��� 30.0 ��� S ���32��37 ��� 53.8 ��� S, 153��08 ��� 31.2 ��� E ���153��09 ��� 42.1 ��� E, depth 1006���1036 m, beam trawl, coll. M. Ekins on RV Investigator, Cruise IN2017_V03, 3 June 2017, fixed in 99.5% EtOH. Description: External morphology. Circa 40 cylindrical polyps connected by strongly developed light beige coenenchyme on stalks of hexactinellid sponges (Hyalonema sp.) in preserved specimen. Colony covered upper part of the stalks, but not around the spiculous anchor. Contracted preserved polyps 1.0���3.0 mm in height, 1.5���3.5 mm in diameter. Remarks: The capitulums of this specimen (QM G337590) were not swollen, while capitulums of the examined specimens of Epizoanthus fatuus (NSMT-Co 1757, NSMT-Co 1758) were swollen when contracted. On the other hand, numbers of tentacles and mesenteries were the same between QM G337590 and the examined specimens of E. fatuus. Therefore, we here preliminarily identify the examined specimen as Epizoanthus aff. fatuus., Published as part of 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, pp. 323-347 in Zoological Journal of the Linnean Society 194 on pages 330-331, DOI: 10.1093/zoolinnean/zlab068, http://zenodo.org/record/5799592, {"references":["Schultze MJS. 1860. Die Hyalonemen. Ein Beitrag zur Naturgeschichte der Spongien. Bonn: A. Marcus, i - iii, 1 - 46."]}

GENUS CHURABANA GEN. NOV. (FIG. 4A–H) Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org:act: EACFCC05-EA56-4F04-94A2-FB716F22004C. Type species: Churabana kuroshioae sp. nov. by original designation. Diagnosis: Parazoanthidae with obligate symbiotic relationship with massive hexasterophoran sponges. Preserved polyps 3.0–4.0 mm in height, 2.8–4.0 mm in diameter. Azooxanthellate. Cteniform endodermal marginal musculature. Remarks: Churabana and other already described sponge-associated zoantharian genera can be easily distinguished from each other by their host sponges (Hexactinellida sponges vs. Demospongiae sponge) and depths; the former can be found at> 140 m, while the latter are found in shallow coral reefs. Although Churabana and several species within Isozoanthus and Epizoanthus are associated with Hexactinellida sponges, these three genera can be distinguished from each other by their hosts: the latter two genera are associated with species within the subclass Amphidiscophora, while species of Churabana are associated with sponge species within the subclass Hexasterophora. Churabana has a unique deletion of 15 bp (from position 168 to 182 in our alignment) in its 16S-rDNA region. Etymology: The generic name is derived from the Ryukyuan language words chura, beautiful, and bana, flower, referring to the appearance of this species. Gender feminine. The Japanese name is 'Chura-tama-sunaginchaku'.

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. FAMILY PARAZOANTHIDAE DELAGE & HEROUARD, 1901 GENUS CHURABANA GEN. NOV. (FIG. 4A���H) Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org:act: EACFCC05-EA56-4F04-94A2-FB716F22004C. Type species: Churabana kuroshioae sp. nov. by original designation. Diagnosis: Parazoanthidae with obligate symbiotic relationship with massive hexasterophoran sponges. Preserved polyps 3.0���4.0 mm in height, 2.8���4.0 mm in diameter. Azooxanthellate. Cteniform endodermal marginal musculature. Remarks: Churabana and other already described sponge-associated zoantharian genera can be easily distinguished from each other by their host sponges (Hexactinellida sponges vs. Demospongiae sponge) and depths; the former can be found at> 140 m, while the latter are found in shallow coral reefs. Although Churabana and several species within Isozoanthus and Epizoanthus are associated with Hexactinellida sponges, these three genera can be distinguished from each other by their hosts: the latter two genera are associated with species within the subclass Amphidiscophora, while species of Churabana are associated with sponge species within the subclass Hexasterophora. Churabana has a unique deletion of 15 bp (from position 168 to 182 in our alignment) in its 16S-rDNA region. Etymology: The generic name is derived from the Ryukyuan language words chura, beautiful, and bana, flower, referring to the appearance of this species. Gender feminine. The Japanese name is 'Chura-tama-sunaginchaku'. GENUS CHURABANA GEN. NOV. (FIG. 4A���H) Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org:act: EACFCC05-EA56-4F04-94A2-FB716F22004C. Type species: Churabana kuroshioae sp. nov. by original designation. Diagnosis: Parazoanthidae with obligate symbiotic relationship with massive hexasterophoran sponges. Preserved polyps 3.0���4.0 mm in height, 2.8���4.0 mm in diameter. Azooxanthellate. Cteniform endodermal marginal musculature. Remarks: Churabana and other already described sponge-associated zoantharian genera can be easily distinguished from each other by their host sponges (Hexactinellida sponges vs. Demospongiae sponge) and depths; the former can be found at> 140 m, while the latter are found in shallow coral reefs. Although Churabana and several species within Isozoanthus and Epizoanthus are associated with Hexactinellida sponges, these three genera can be distinguished from each other by their hosts: the latter two genera are associated with species within the subclass Amphidiscophora, while species of Churabana are associated with sponge species within the subclass Hexasterophora. Churabana has a unique deletion of 15 bp (from position 168 to 182 in our alignment) in its 16S-rDNA region. Etymology: The generic name is derived from the Ryukyuan language words chura, beautiful, and bana, flower, referring to the appearance of this species. Gender feminine. The Japanese name is 'Chura-tama-sunaginchaku'., Published as part of 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, pp. 323-347 in Zoological Journal of the Linnean Society 194 on pages 332-333, DOI: 10.1093/zoolinnean/zlab068, http://zenodo.org/record/5799592, {"references":["Carlgren O. 1923. Ceriantharia und zoantharia der deutschen tiefsee-expedition. Zoantharia. Wissenschaftliche Ergebnisse der Deutschen Tiefsee-Expedition auf dem Dampfer ' Valdivia' 1898 - 1899 19: 252 - 337.","Kise H, Dewa N, Reimer JD. 2018. First record of sea urchinassociated Epizoanthus planus from Japanese waters and its morphology and molecular phylogeny. Plankton and Benthos Research 13: 136 - 141.","Delage Y, Herouard E. 1901. Zoanthides - Zoanthidea. In: Traitede Zoologie concrete. Tome II - 2 me Partie. Les Coelenteres. Paris: C. Reinwald, 654 - 667. Available at: https: // gallica. bnf. fr / ark: / 12148 / bpt 6 k 5597996 v. texteImage"]}

GENUS EPIZOANTHUS GRAY, 1867 Type species: Dysidea papillosa Johnston, 1842, by monotypy (see also Opinion 1689 in ICZN, 1992). Diagnosis: Macrocnemic zoantharians with simple mesogleal musculature, readily distinguishable from Palaeozoanthus by the presence of non-fertile micromesenteries (Sinniger & H��ussermann 2009)., Published as part of 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, pp. 323-347 in Zoological Journal of the Linnean Society 194 on page 327, DOI: 10.1093/zoolinnean/zlab068, http://zenodo.org/record/5799592, {"references":["Gray JE. 1867. Notes on Zoanthinae, with descriptions of some new genera. Proceedings of the Zoological Society of London 15: 233 - 240.","Johnston G. 1842. A history of British sponges and lithophytes. Edinburgh, London & Dublin: Publisher","ICZN 1992. Opinion 1689. Epizoanthus Gray, 1867 (Cnidaria, Anthozoa): conserved. Bulletin of Zoological Nomenclature 49: 236 - 237.","Sinniger F, Haussermann V. 2009. Zoanthids (Cnidaria: Hexacorallia: Zoantharia) from shallow waters of the southern Chilean fjord region, with descriptions of a new genus and two new species. Organisms Diversity & Evolution 9: 23 - 36."]}

VITRUMANTHUS SCHRIERI SP. NOV. (FIG. 6A���F) Synonymy: Parazoanthidae sp. ��� Montenegro et al., 2020: 7���8, fig. 2; ���zoanthid symbionts���, ���zoanthids��� ��� Reiswig & Dohrmann, 2014: 241���242, fig. 4A, B; ���white zoanthids��� ��� Van Soest et al., 2014: 438. Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org:act: D326729E-6617-4C5F-8F43-31C5C7133EF4. Material examined: Holotype: RMNH.COEL.42429, SubStation, Cura��ao, 12��14 ��� 01 ��� N, 68��53 ��� 32 ��� W, depth range 161���243 m, manned submarine Curasub, coll. B. W. Hoeksema, 31 Mar 2014, fixed in 99.5% ethanol. Paratype: RMNH.COEL.42430, SubStation, Cura��ao, 12��05 ��� 04 ��� N, 68��53 ��� 54 ��� W, c. 200 m deep, manned submarine Curasub, coll. B. W. Hoeksema, 21 Apr 2014, fixed in 99.5% ethanol. Other material examined: RMNH.COEL.42620, Cargill Pier, Bonaire, Caribbean Netherlands, 12��04 ��� 47.9 ��� N, 68��17 ��� 37.7 ��� W, depth 223 m, manned submarine Curasub based on RV Chapman, coll. L. Becking and E. Meesters, 1 Jun 2013, fixed in 99.5% ethanol. RMNH.COEL.42621, Cargill Pier, Bonaire, Caribbean Netherlands, 12��04 ��� 47.9 ��� N, 68��17 ��� 37.7 ��� W, depth 248 m, manned submarine Curasub based on RV Chapman, coll. L. Becking and E. Meesters, 1 Jun 2013, fixed in 99.5% ethanol. RMNH.COEL.42622, Kralendijk Pier, Bonaire, Caribbean Netherlands, 12��08 ��� 48.9 ��� N, 68��16 ��� 55.6 ��� W, depth 140 m, manned submarine Curasub based on RV Chapman, coll. L. Becking and E. Meesters, 30 May 2013, fixed in 99.5% ethanol. Etymology: The species is named for Adriaan ���Dutch��� Schrier, owner of the manned submersible Curasub and RV Chapman, operated from Substation Cura��ao, for his generosity in allowing BWH to sample specimens. The Japanese name is 'Amime-ruri-sunaginchaku'. Description: External morphology. Circa 50 cylindrical polyps in preserved specimen. Solitary or colonial polyps rise irregularly from the hexactinellid sponge Verrucocoeloidea liberatoriii Reswig & Dohrmann, 2014. Living polyps white and tentacle transparent in coloration. Preserved polyps dark beige. Surface of column rough and ectoderm continuous. Ectoderm and mesoglea of polyps encrusted with numerous and various sizes of sand and silica particles. The living expanded oral disks c. up to 8.0 mm in diameter, expanded polyps c. up to 10 mm in height, 1.0���5.0 mm in diameter. Preserved contracted preserved polyps 0.3���2.1 mm in height, 0.8���2.8 mm in diameter. Capitulary ridges indiscernible. Tentacles 20���24 in number. Internal morphology. Zooxanthellae absent. Cyclically transitional marginal musculature. Encircling sinus present and basal canals of mesenteries absent. Mesenteries thin. Mesoglea thickness c. 0.6 mm. Mesoglea thicker than ectoderm and endoderm. Siphonoglyph distinct and V-shaped. Mesenterial filaments present. Cnidae. Basitrichs and microbasic b-mastigophores, microbasic p-mastigophores, holotrichs and spirocysts (Fig. 5B; Table 2). Distribution and habitats: Caribbean Netherlands: known from Cura��ao and Bonaire at depths of 140��� 248 m. Associated hosts: Verrucocoeloidea liberatorii Reswig & Dohrmann, 2014, Parahigginsia strongylifera Van Soest, Meesters & Becking, 2014 and Cyrtaulon sigsbeei (Schmidt, 1880). Remarks: In terms of host hexactinellid sponges, Vitrumanthus schrieri can be distinguished from V. vanderlandi and V. oligomyarius (Wassilieff, 1908) because only V. schrieri is associated with Verrucocoeloidea sponges. Vitrumanthus schrieri is not only associated with hexactinellid sponges, but also with Demospongiae species in the genus Parahigginsia (Van Soest et al., 2014). On the other hand, V. vanderlandi and V. oligomyarius are associated with Tretochone duplicata (Topsent, 1928). In addition, the column of V. schrieri is rough, due to heavy encrustation, while columns of V. vanderlandi and V. oligomyarius are smooth with almost no encrustations. Vitrumanthus sp. (NSMT-Co 1755) and V. vanderlandi are associated with Cyrtaulon species. Reiswig & Dohrmann (2014) reported zoantharians were found on Verrucocoeloidea liberatorii, and we judge that these are likely V. schrieri based on external morphology and the host hexactinellid sponge species., Published as part of 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, pp. 323-347 in Zoological Journal of the Linnean Society 194 on pages 337-339, DOI: 10.1093/zoolinnean/zlab068, http://zenodo.org/record/5799592, {"references":["Montenegro J, Hoeksema BW, Santos MEA, Kise H, Reimer JD. 2020. Zoantharia (Cnidaria: Hexacorallia) of the Dutch Caribbean with historical distribution records from the Atlantic and one new species of Parazoanthus. Diversity 12 (5): 190.","Reiswig HM, Dohrmann M. 2014. Three new species of glass sponges (Porifera: Hexactinellida) from the West Indies, and molecular phylogenetics of Euretidae and Auloplacidae (Sceptrulophora). Zoological Journal of the Linnean Society 171: 233 - 253.","Van Soest RW, Meesters EH, Becking LE. 2014. Deepwater sponges (Porifera) from Bonaire and Klein Curacao, Southern Caribbean. Zootaxa 3878: 401 - 443.","Schmidt O. 1880. Die Spongien des meerbusen von Mexico (Und des caraibischen Meeres). Heft II. Abtheilung II. Hexactinelliden. Abtheilung III. Tetractinelliden. Monactinelliden und Anhang. Nachtrage zu Abtheilung I (Lithistiden). In: Reports on the dredging under the supervision of Alexander Agassiz, in the Gulf of Mexico, by the USCSS ' Blake'. Jena: Gustav Fischer, 33 - 90.","Wassilieff A. 1908. Japanische actinien, in Doflein. Abhandlungen der Mathematisch-Physikalischen Klasse der Koniglich Bayerischen Akademie der Wissenschaften 1: 1 - 49.","Topsent E. 1928. Sur deux Euretides du Japon. (Note preliminaire). Bulletin de l'Institut oceanographique de Monaco 515: 1 - 4."]}

CHURABANA KUROSHIOAE SP. NOV. (FIG. 4A–I) Synonymy: Parazoanthidae sp. 1 — Reimer et al., 2019: 7, fig. 2A. Zoobank registration: u r n: l s i d: z o o b a n k. org:act: FC503255-BDC2-45C5-9788-41F52BC40FA5. Material examined: Holotype: RUMF-ZG-04447, near Iejima Island, Motobu, Okinawa, Japan, 26°54 ′ 53.6 ″ N, 127°37 ′ 50.9 ″ E, 600–650 m, baskets, coll. T. Higashiji on vessel Daini-kuroshio-maru, 2 March 2018, divided into two pieces, one portion fixed in 5–10% saltwater formalin and other in 99.5% ethanol. Paratype: RUMF-ZG-04448, near Iejima Island, Motobu, Okinawa, Japan, 26°54’53.6 ″ N, 127°37 ′ 50.9 ″ E, 600–650 m, baskets, coll. T. Higashiji on vessel Dainikuroshio-maru, 2 March 2018, fixed in 99.5% ethanol. MISE-JMG51J (NSMT-Co 1754), Nanpo Trough, Kikaijima Island, Kagoshima, Japan, 28°20 ′ 21.64 ″ N, 129°57 ′ 14.56 ″ E, depth 520 m, ROV, coll. Javier Montenegro on RV Natsushima, 14 Oct 2011, fixed in 99.5% ethanol. Etymology: The species is named after the Dainik u r o s h i o -m a r u, a s t h e t y p e s p e c i m e n s w e r e collected by this vessel. The Japanese name is 'Beni-chura-tama-sunaginchaku'. Description: External morphology. Four truncated cone-shaped or cylindrical polyps in preserved specimen. The polyp bases embedded within the sponge Pararete Ijima, 1927. Solitary polyps arise irregularly from Pararete specimens. The living polyps cream-pink or beige and tentacles cream or whitish transparent in coloration. Preserved polyps beige and partially red. Surface of column rough and ectoderm continuous. Ectoderm and mesoglea of polyps encrusted with numerous and various sizes of sand and silica particles. The living expanded oral disks c. 1.5– 2.0 mm in diameter, expanded polyps c. up to 10 mm in height, 4.0–5.0 mm in diameter. Preserved contracted preserved polyps 3.0–4.0 mm in height, 2.8–4.0 mm in diameter. Capitulary ridges discernible, 15–16 in number when contracted. 30–32 tentacles in number. Internal morphology. Zooxanthellae absent. Cteniform endodermal marginal musculature. Encircling sinus present and basal canals of mesenteries absent. Mesenteries thin, 30–32 in macrocnemic arrangement. Mesoglea thickness 0.5–1.6 mm. Mesoglea thicker than ectoderm and endoderm. Siphonoglyph distinct and U-shaped. Mesenterial filaments present. Cnidae. Basitrichs and microbasic b-mastigophores, microbasic p-mastigophores, holotrichs and spirocysts (Fig. 5A; Table 2). Distribution and habitats: Ryukyu Archipelago, Japan: Near Iejima Island, Okinawa and Nanpo Trough, Kikaijima Island, Kagoshima, Japan at depths of 520– 650 m. Associated host: Pararete sp. 1 and Pararete sp. 2. R e m a r k s: C h u r a b a n a k u r o s h i o a e r e s e m b l e s Vitrumanthus species, but they can be easily separated by differences in their marginal musculatures (see also Remarks under Vitrumanthus).

VITRUMANTHUS SCHRIERI SP. NOV. (FIG. 6A–F) Synonymy: Parazoanthidae sp. – Montenegro et al., 2020: 7–8, fig. 2; ‘zoanthid symbionts’, ‘zoanthids’ – Reiswig & Dohrmann, 2014: 241–242, fig. 4A, B; ‘white zoanthids’ – Van Soest et al., 2014: 438. Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org:act: D326729E-6617-4C5F-8F43-31C5C7133EF4. Material examined: Holotype: RMNH.COEL.42429, SubStation, Curaçao, 12°14 ′ 01 ″ N, 68°53 ′ 32 ″ W, depth range 161–243 m, manned submarine Curasub, coll. B. W. Hoeksema, 31 Mar 2014, fixed in 99.5% ethanol. Paratype: RMNH.COEL.42430, SubStation, Curaçao, 12°05 ′ 04 ″ N, 68°53 ′ 54 ″ W, c. 200 m deep, manned submarine Curasub, coll. B. W. Hoeksema, 21 Apr 2014, fixed in 99.5% ethanol. Other material examined: RMNH.COEL.42620, Cargill Pier, Bonaire, Caribbean Netherlands, 12°04 ′ 47.9 ″ N, 68°17 ′ 37.7 ″ W, depth 223 m, manned submarine Curasub based on RV Chapman, coll. L. Becking and E. Meesters, 1 Jun 2013, fixed in 99.5% ethanol. RMNH.COEL.42621, Cargill Pier, Bonaire, Caribbean Netherlands, 12°04 ′ 47.9 ″ N, 68°17 ′ 37.7 ″ W, depth 248 m, manned submarine Curasub based on RV Chapman, coll. L. Becking and E. Meesters, 1 Jun 2013, fixed in 99.5% ethanol. RMNH.COEL.42622, Kralendijk Pier, Bonaire, Caribbean Netherlands, 12°08 ′ 48.9 ″ N, 68°16 ′ 55.6 ″ W, depth 140 m, manned submarine Curasub based on RV Chapman, coll. L. Becking and E. Meesters, 30 May 2013, fixed in 99.5% ethanol. Etymology: The species is named for Adriaan ‘Dutch’ Schrier, owner of the manned submersible Curasub and RV Chapman, operated from Substation Curaçao, for his generosity in allowing BWH to sample specimens. The Japanese name is 'Amime-ruri-sunaginchaku'. Description: External morphology. Circa 50 cylindrical polyps in preserved specimen. Solitary or colonial polyps rise irregularly from the hexactinellid sponge Verrucocoeloidea liberatoriii Reswig & Dohrmann, 2014. Living polyps white and tentacle transparent in coloration. Preserved polyps dark beige. Surface of column rough and ectoderm continuous. Ectoderm and mesoglea of polyps encrusted with numerous and various sizes of sand and silica particles. The living expanded oral disks c. up to 8.0 mm in diameter, expanded polyps c. up to 10 mm in height, 1.0–5.0 mm in diameter. Preserved contracted preserved polyps 0.3–2.1 mm in height, 0.8–2.8 mm in diameter. Capitulary ridges indiscernible. Tentacles 20–24 in number. Internal morphology. Zooxanthellae absent. Cyclically transitional marginal musculature. Encircling sinus present and basal canals of mesenteries absent. Mesenteries thin. Mesoglea thickness c. 0.6 mm. Mesoglea thicker than ectoderm and endoderm. Siphonoglyph distinct and V-shaped. Mesenterial filaments present. Cnidae. Basitrichs and microbasic b-mastigophores, microbasic p-mastigophores, holotrichs and spirocysts (Fig. 5B; Table 2). Distribution and habitats: Caribbean Netherlands: known from Curaçao and Bonaire at depths of 140– 248 m. Associated hosts: Verrucocoeloidea liberatorii Reswig & Dohrmann, 2014, Parahigginsia strongylifera Van Soest, Meesters & Becking, 2014 and Cyrtaulon sigsbeei (Schmidt, 1880). Remarks: In terms of host hexactinellid sponges, Vitrumanthus schrieri can be distinguished from V. vanderlandi and V. oligomyarius (Wassilieff, 1908) because only V. schrieri is associated with Verrucocoeloidea sponges. Vitrumanthus schrieri is not only associated with hexactinellid sponges, but also with Demospongiae species in the genus Parahigginsia (Van Soest et al., 2014). On the other hand, V. vanderlandi and V. oligomyarius are associated with Tretochone duplicata (Topsent, 1928). In addition, the column of V. schrieri is rough, due to heavy encrustation, while columns of V. vanderlandi and V. oligomyarius are smooth with almost no encrustations. Vitrumanthus sp. (NSMT-Co 1755) and V. vanderlandi are associated with Cyrtaulon species. Reiswig & Dohrmann (2014) reported zoantharians were found on Verrucocoeloidea liberatorii, and we judge that these are likely V. schrieri based on external morphology and the host hexactinellid sponge species.