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