Ceriantharia (Cnidaria) from Australia, New Zealand and Antarctica with Descriptions of Four New Species Author Stampar, Sérgio N. Laboratório de Evolução e Diversidade Aquática-LEDA, Departamento de Ciências Biológicas, Universidade Estadual Paulista (UNESP), FCL / Assis, Av. Dom Antônio, 2100, 19806 - 900, Assis, SP, Brazil Author Mills, V. Sadie NIWA Invertebrate Collection, National Institute of Water and Atmospheric Research, 301 Evans Bay Parade Hataitai, 6021 Wellington, New Zealand Author Keable, Stephen J. Australian Museum Research Institute, Australian Museum, 1 William Street, Sydney NSW 2010, Australia text Records of the Australian Museum 2020 2020-07-29 72 3 81 100 journal article 10.3853/j.2201-4349.72.2020.1762 2201-4349 4654407 62E3C79A-499F-48DE-AFD9-111D52235D33 Pachycerianthus nobilis ( Haddon & Shackleton, 1893 ) Cerianthus nobilis Haddon & Shackleton, 1893: 116 , 118; Carlgren, 1896: 174; Haddon, 1898: 400–401 ; Pax, 1910: 167 . Pachycerianthus nobilis Molodtsova, 2000: 19 ; Molodtsova, 2007: 133 ; Stampar et al. , 2014: 350, 352. Specimens examined . AM G16074, Dunwich , Stradbroke Island , Moreton Bay , Queensland , Australia , 27.50°S 153.40°E (1974) ; AM G18351, Dunwich , Stradbroke Island , Moreton Bay , Queensland , Australia ( 06/viii/1961 ), on sand flats ( 5 specimens ); Museum and Art Gallery of the Northern Territory : NTM CO14354 , Town Hall , Channel Island , Darwin Harbor , Darwin , Northern Territory , Australia , 12.550°S 130.833°E , 6–8 m depth . Remarks . The specimens studied come from southern Queensland and the northern part of the Northern Territory . As this species has been described from Torres Strait in northern Queensland , the distribution appears to be quite broad, encompassing the Timor Sea, Arafura Sea and Coral Sea. The polyps generally have a whitish-green color in the tentacle region and reddish-brown color in the column. However, some live specimens have different tentacle colors, including purple to green marginal tentacles. All specimens examined were fertile, including those smaller than 3 cm in length. This indicates that reproductive maturity is reached rapidly and long before specimens reach the maximum reported size for the species ( 10 cm in preserved specimens). This is a very little studied species but is apparently common and of commercial importance as it is sold in aquarium stores to amateur hobbyists (SNS personal observation). Therefore, an assessment of conservation status and reproductive patterns of this species would be valuable. Figure 6 . Graphical representation of the arrangement of mesenteries of Pachycerianthus antarcticus sp. nov. Abbreviations: M.C., multiplication chamber; dm, directives; T.P., terminal pore; S, siphonoglyph; B, betamesenteries (convoluted mesentery); M, metamesenteries (double filament); P, protomesenteries. Table 2 . Cnidome of Pachycerianthus antarcticus sp. nov. based on two specimens (NIWA 36894 and 103267). Mean and range given for each cnida.

Pachycerianthus antarcticus sp. nov.
length (in µm)	width (in µm)
column
pytchocysts	59.9 (53.5–65.2)	16.5 (14.5–19.2)
holotrich	64.5 (59.5–69.3)	18.2 (14.5–19.2)
atrichs	36.4 (32.5–40.5)	8.2 (5.1–9.9)
b-mastigophores ii	29.5 (27.7–33.5)	6.9 (5.8–7.7)
b-mastigophores iii	26.8 (23.9–27.9)	7.6 (6.5–8.6)
marginal tentacles
b-mastigophores iv	18.7 (75.6–92.3)	6.1 (5.4–6.9)
atrichs	32.6 (31.7–36.6)	7.2 (6.6–7.9)
labial tentacles
b-mastigophores i	86.7 (75.6–92.3)	10.1 (8.9–11.7)
b-mastigophores ii	29.4 (26.3–32.9)	6.6 (5.7–7.5)
atrichs	38.5 (34.1–40.6)	8.3 (5.5–10.2)
stomodeum
b-mastigophores i	84.5 (72.5–89.6)	9.8 (8.5–10.9)
b-mastigophores ii	28.6 (27.1–29.9)	6.6 (6.2–7.2)
atrichs	30.7 (29.2–32.5)	7.9 (7.1–8.6)
mesenteries Type b
atrichs	30.9 (29.4–33.2)	8.1 (6.9–9.2)
mesenteries Type m
b-mastigophores ii	30.8 (29.2–33.1)	6.7 (6.2–7.3)

Distribution . Queensland and Northern Territory , Australia , New Caledonia , depth: shallow waters.