Umimayanthus wunanggu, Montenegro & Fromont & Richards & Kise & Gomez & Hoeksema & Reimer, 2024

Montenegro, Javier, Fromont, Jane, Richards, Zoe, Kise, Hiroki, Gomez, Oliver, Hoeksema, Bert W. & Reimer, James Davis, 2024, Museum collections as untapped sources of undescribed diversity of sponge-zoantharian associations with the description of six new species of Umimayanthus (Zoantharia: Parazoanthidae) from Western Australia and eastern Indonesia, Contributions to Zoology 93 (5), pp. 466-522 : 494-498

Umimayanthus wunanggu sp. nov.

Montenegro, Kise & Reimer urn:lsid:zoobank.org:act:E0D67C58-5506-4700-9F44-98C4789A27F7

Etymology. The specific epithet “wunanggu ” is derived from the phoneme used to refer to the hill white gum tree in Wunambal language. This in reference to U. wunanggu sp. nov. forming colonies of white polyps connected by a thin coenenchyma that extends on a linear branching pattern over the sponge surface. “wunanggu winya” n., W-class. /wunaŋgu/. hill white gum, tropical red box, Eucalyptus brachyandra von Mueller, 1859 . See Capell (1941) and Karadada (2011).

Material examined. Type locality: Eclipse Is. [loc. 20], − 13.794197 °S, 126.11881 °E, Western Australia ( fig. 1) .

Holotype. WAM Z88826 (− 13.794197 °S, 126.11881 °E, loc. 20, Eclipse Is., Western Australia, 59 m depth, March 7, 2016 by O.A. Gomez & J.A. Ritchie) . Paratype 1: WAM Z88822 (− 14.401883 °S, 124.944067 °E, loc. 18, Maret Is. Western Australia, 50 m depth, December 8, 2015 by O.A. Gomez & J.A. Ritchie) . Paratype 2: WAM Z88818 (− 15.446442 °S, 124.083022 °E, loc. 15, Camden Sound , Western Australia, 61 m depth, March 20, 2015 by J. Fromont & L. Kirkendale) .

Other material. One additional examined specimen belonging to the Western Australian Museum ; WAM Z88827 (− 15.6233 °S, 121.972233 °E, loc. 13, Lynher Bank, Western Australia, 61 m depth, October 28, 2016 by J. Fromont & J.A. Ritchie) .

Diagnosis. U. wunanggu sp. nov. can be distinguished from all other spongeassociated zoantharians by its symbiotic associations with sponges in the genus Endectyon , and forming colonies of polyps connected by a thin coenenchyma that extends linearly over the host sponge surface; currently known to establish associations with Endectyon (Endectyon) fruticosum and Endectyon (Endectyon)

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thurstoni (Dendy, 1887) . Additionally, unique substitutions across the ITS-rDNA region set this species apart from other species in the genus Umimayanthus , as follows: “C” in positions 360 bp, 421 bp, and 426 bp; “TTAC” from positions 423–426 bp; “A” in position 704 bp; and a unique combination of nucleotides, “AA” between position 704–705 bp, and “CG” in 816–817 bp ( fig. 12).

Description. Size: Preserved polyps are on average 2.4 mm ± 0.22 mm (σ2 = 0.05, max. 2.79 mm, n = 12 polyps) in diameter, and 0.92 mm ± 0.36 mm (σ2 = 0.13, max. 1.77 mm, n = 12 polyps) in height. All measurements were performed on voucher specimens preserved in ethanol: zoantharian voucher numbers WAM Z88826, WAM Z88822, WAM Z88818, and WAM Z88827.

Morphology. The holotype specimen is associated with Endectyon (Endectyon) thurstoni . The polyp diameter of U. wunanggu sp. nov. is remarkably constant, 2.2~ 2.8 mm across all analysed specimens. All specimens were colonies with polyps extended well over the sponge surface. Most specimens had polyps connected by a well-developed coenenchyma, forming

CONTRIBUTIONS TO ZOOLOGY 93 (2024) 466–522

CONTRIBUTIONS TO ZOOLOGY 93 (2024) 466–522

chains of polyps in branches rather than in a reticulate pattern, different from U. cf. aruensis . Capitulary ridges were visible, 14–18 in number. Tentacles were approximately up to 36 in number. Preserved tentacles were light brown in coloration. Capitulum and scapus were heavily encrusted by various particles of sand and silica (= spicules of host sponges). Polyps preserved in ethanol were white or cream in color.

Cnidae. Except for holotrich (S), all categories of cnidae were found. The cnidae composition across tentacles and pharynx was similar and made up of spirocysts, holotrichs (L) and (M), bastrichs and microbasic b-mastigophores. The column had the lowest diversity of cnidae with only holotrichs (L) and (M). In contrast the mesenterial filaments had the largest diversity of cnidae, including holotrichs (L) and (M), microbasic p-mastigophores, bastrichs and microbasic b-mastigophores and special microbasic b-mastigophores. For details on sizes, lengths, and widths of each cnidae type, see table 4 and fig. 13.

Internal morphology. Sphincter muscle was located in the endoderm. Mesenterial arrangement was macrocnemic. Mesenteries were approximately up to 28 in number. Ectoderm and mesoglea of capitulum and scapus were heavily encrusted by various sand and silica particles. Single siphonoglyph.

Distribution. All specimens analysed were collected along the west coast of Western Australia. Lynher Bank [loc. 13], Camden Sound [Loc. 15], Maret Is. [loc. 18] and Eclipse Is. [loc. 20] ( fig. 1). Specimens were found at depths of 50– 61 m.

Associated host. Umimayanthus wunanggu sp. nov. was associated with four sponges in two species in the family Raspailiidae Nardo, 1833 , Endectyon (Endectyon) thurstoni (n = 3) and Endectyon (Endectyon) fruticosum (n = 1). The type locality of Endectyon (Endectyon) thurstoni is India, and this species has also been reported from the Arabian Sea and Western Australia. The type locality of Endectyon (Endectyon) fruticosum is also India and it has additionally been reported from the Aru Islands, Indonesia, the south Andaman Sea, Thailand ( Hooper, 1991), and now from the Kimberley region, Western Australia. Based on this wide host sponge distribution, it may be that the distribution of U. wunanggu sp. nov. is wider than currently known.

Remarks. Umimayanthus wunanggu sp. nov., Umimayanthus mirnangga sp. nov. and Umimayanthus jebarra sp. nov. are

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sibling species that were shown to be closely related in our phylogenetic analyses. Nonetheless, key diagnostic molecular and morphological characters, including the general external morphology of the colonies and the height of the polyps, as well as the different host species, clearly separate these three species from each other. For details refer to each of the species formal description.