New Species of Osedax (Siboglinidae: Annelida) from New Zealand and the Gulf of Mexico Author Berman, Gabriella H. Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093 - 0202, USA Author Hiley, Avery S. Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093 - 0202, USA Author Read, Geoffrey B. National Institute of Water & Atmospheric Research (NIWA), 301 Evans Bay Parade, Hataitai, Wellington New Zealand Author Rouse, Greg W. Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093 - 0202, USA text Zootaxa 2024 2024-04-23 5443 3 337 352 http://dx.doi.org/10.11646/zootaxa.5443.3.2 journal article 10.11646/zootaxa.5443.3.2 1175-5326 11045291 AB6A5DE3-D85B-4103-A92F-917936F19EF3 Osedax bozoi n. sp. Fig. 3A , 4A–D , 6A Material examined. Holotype : SIO-BIC A13918, female (GenBank COI sequence ON357631), collected from experimentally deployed cow bones deployed at 1,996 m depth in the Gulf of Mexico , offshore of New Orleans , Louisiana ( 28.103° N ; 88.451° W ); ROV Global Explorer dive number 17, April 15, 2019 ; fixed and preserved in 95% ethanol . Paratypes : SIO-BIC A10278 (destroyed, GenBank numbers in Table 2 ), A13920 (GenBank COI sequence ON357630), A13922 (GenBank COI sequences ON357686), females, collection data for paratypes is the same as for the holotype . Diagnosis and description. Preserved holotype and other specimens white with greenish patches on root/ ovisac ( Fig. 4A–D ). Four apinnulate palps, distally coiled, ~ 1.5 mm long, ~ 0.2 mm wide, mainly contained inside transparent tube ( Fig. 4A–D ). Trunk ~ 0.5 mm long, 0.2–0.4 mm wide ( Fig. 4A, B, D ). Clear demarcation between palps and trunk; small ‘collar’ visible ventrally at truck/palp junction ( Fig. 4B ). Oviduct visible dorsally along trunk and extends into crown of palps, complete length unknown ( Fig. 4A ). Roots incomplete in holotype ( Fig. 4B–D ), though root extensions may be present on either side of the trunk ( Fig. 4B, D ). Paratype SIO-BIC A13922 with lobed ovisac, lateral root lobes, root extensions present on either side of the trunk ( Fig. 4D ). No dwarf males observed. The rDNC diagnosis for Osedax bozoi n. sp. was recovered as: ‘C’ at site 465, ‘G’ at site 468, and ‘T’ at site 561 of mitochondrial COI. Distribution. Osedax bozoi n. sp. was recovered from cow bones ( Fig. 3A ) deployed at 1,996 m in the Mississippi River Delta region of the Gulf of Mexico south of New Orleans, Louisiana ( Fig. 1 ). Etymology. Osedax bozoi n. sp. is named for the first author’s late cat, Bozo. Remarks. Osedax bozoi n. sp. belongs to Clade II ( Fig. 2 ), an apinnulate ‘nude palp’ clade. Only associated with deployed cow bones ( Fig. 3A ). Paratype SIO-BIC A10278 was sequenced for 16S , 18S , 28S , and H3 as well as COI ( Table 2 ), but the specimen was destroyed for DNA extraction. SIO-BIC A13918, which had a close COI sequence and was largely intact, has been designated as the holotype ( Fig. 4A, B ). Specimens SIO-BIC A10276 (ON357629) and SIO-BIC A10277 (ON357628) were also destroyed for sequencing COI . Osedax bozoi n. sp. had a 1.3% maximum pairwise distance among the six available sequences, which all showed the rDNC diagnostic bases. The haplotype network for Osedax bozoi n. sp. had four unique haplotypes ( Fig. 6A ). One was shared by three of the six sequences, including the holotype . There were three nucleotide substitutions between the most divergent haplotypes, based on a trimmed datafile of 344 bases. Osedax bozoi n. sp. was recovered as the sister group to a clade within Clade II that comprised O. docricketts , O. westernflyer and O. knutei ( Fig. 2 ), though this was poorly supported. These three taxa are all from the Pacific Ocean. In terms of phylogenetic relatedness, the nearest species was Osedax docricketts , an apinnulate species known from Monterey Bay ( California , USA ) and Sagami Bay ( Japan ) on cow and whale bones ( Rouse et al. 2018 ). Osedax bozoi n. sp. and O. docricketts share some morphological characteristics: both lack pigmentation on the trunk and palps and pinnules, both have a tube containing the palps. However, where O. bozoi n. sp. has a distinct demarcation between the palps and the trunk, O. docricketts does not, and the ovisac and oviduct are distinctive on O. bozoi . Osedax docricketts is suspected to be a cryptic species complex ( Berman et al. 2023 ; Rouse et al. 2018 ) and the minimum interspecific distance between the two species was 13.7% based on sequence EU267676, an individual of Osedax docricketts from Monterey Bay ( Table 3 ).