Register      Login
Invertebrate Systematics Invertebrate Systematics Society
Systematics, phylogeny and biogeography
RESEARCH ARTICLE

An ocean yet to be discovered: increasing systematic knowledge of Indo-Pacific Okenia Menke, 1830 (Nudibranchia : Goniodorididae)

Sofía Paz-Sedano https://orcid.org/0000-0001-7466-1627 A G , Nerida G. Wilson https://orcid.org/0000-0002-0784-0200 B C , Leila Carmona D , Terrence M. Gosliner E and Marta Pola A F
+ Author Affiliations
- Author Affiliations

A Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Campus de Excelencia Internacional UAM + CSIC, Madrid, Spain.

B Collections & Research, Western Australian Museum, Welshpool, WA 6106, Australia.

C School of Biological Sciences, University of Western Australia, Perth, WA 6009, Australia.

D Instituto Universitario de Investigación Marina (INMAR), Universidad de Cádiz, Puerto Real, Cádiz, Spain.

E Department of Invertebrate Zoology, California Academy of Sciences, San Francisco, CA 94118, USA.

F Centro de Investigación en Biodiversidad y Cambio Global (CIBC-UAM), Campus de Excelencia Internacional UAM + CSIC, Madrid, Spain.

G Corresponding author. Email: sofia.paz@uam.es

Invertebrate Systematics 35(7) 797-825 https://doi.org/10.1071/IS20088
Submitted: 29 December 2020  Accepted: 22 April 2021   Published: 23 September 2021

Abstract

Numerous faunistic and ecological studies have been conducted throughout the Indo-Pacific Ocean to assess its biodiversity. Despite the abundance of research, studies on the species that inhabit the Indo-Pacific are still necessary due to its extent and high species richness. The major species richness of the genus Okenia Menke, 1830 (Nudibranchia, Goniodorididae) is found in the Indo-Pacific Ocean, including 38 of 60 valid species. Nevertheless, this number does not represent the real biodiversity, since at least 20 more species are already reported in field-guides as undescribed species belonging to this genus. The systematics of the genus Okenia are still unclear since it has been the subject of only a few and incomplete studies. In the present paper, we describe five new Okenia species from the coastlines of Japan, Mozambique and Australia: Okenia aurorapapillata sp. nov., Okenia elisae sp. nov., Okenia nakanoae sp. nov., Okenia siderata sp. nov. and Okenia tenuifibrata sp. nov. Moreover, anatomical details not previously described of Okenia atkinsonorum, Okenia barnardi, Okenia cf. echinata, Okenia hallucigenia, Okenia hiroi, Okenia japonica, Okenia pellucida, Okenia pilosa and Okenia rhinorma are provided. New partial sequences of standard markers (COI, 16S rRNA and H3) were obtained and a phylogenetic analysis that included all species with available data was performed.

ZOOBANK urn:lsid:zoobank.org:pub:28AE2536-A264–4194–8AE3-C430620572E7

Keywords: new species, phylogeny, taxonomy, Japan, Mozambique, Australia.


References

Abe, T. (1964). ‘Opisthobranchia of Toyama Bay and Adjacent Waters, Collected and Figured mainly by the Members of the Biological Club, Takaoka Senior High School, Toyama Pref.’ (Hokuryukan: Tokio, Japan.)

Ahrens, D., Fujisawa, T., Krammer, H. J., Eberle, J., Fabrizi, S., and Vogler, A. P. (2016). Rarity and incomplete sampling in DNA-based species delimitation. Systematic Biology 65, 478–494.
Rarity and incomplete sampling in DNA-based species delimitation.Crossref | GoogleScholarGoogle Scholar | 26797695PubMed |

Alfaro, M. E., Zoller, S., and Lutzoni, F. (2003). Bayes or bootstraps? A simulation study comparing the performance of Bayesian Markov chain Monte Carlo sampling and bootstrapping in assessing phylogenetic confidence. Molecular Biology and Evolution 20, 255–266.
Bayes or bootstraps? A simulation study comparing the performance of Bayesian Markov chain Monte Carlo sampling and bootstrapping in assessing phylogenetic confidence.Crossref | GoogleScholarGoogle Scholar | 12598693PubMed |

Anderson, J. (2019). Okenia japonica. In ‘The Slug Site’. Available at http://slugsite.us/bow2007/nudwk1088.htm

Atkinson, D. (1999). Observations on Hopkinsia sp. In ‘Sea Slug Forum’. (Australian Museum: Sydney, NSW, Australia.) Available at http://www.seaslugforum.net/find/522

Ayyagari, V. S., and Sreerama, K. (2020). Molecular phylogeny and evolution of Pulmonata (Mollusca: Gastropoda) on the basis of mitochondrial (16S, COI) and nuclear markers (18S, 28S): an overview. Journal of Genetics 99, 17.
Molecular phylogeny and evolution of Pulmonata (Mollusca: Gastropoda) on the basis of mitochondrial (16S, COI) and nuclear markers (18S, 28S): an overview.Crossref | GoogleScholarGoogle Scholar |

Baba, K. (1937). Opisthobranchia of Japan (II). Journal of the Faculty of Agriculture, Kyushu University 5, 289–344.
Opisthobranchia of Japan (II).Crossref | GoogleScholarGoogle Scholar |

Baba, K. (1938). Opisthobranchia of Kii, Middle Japan. Journal of the Faculty of Agriculture, Kyushu University 6, 1–19.
Opisthobranchia of Kii, Middle Japan.Crossref | GoogleScholarGoogle Scholar |

Baba, K. (1940). Some additions to the nudibranch fauna of the northern part of Japan. Nihon Seibutsu Chiri Gakkai Kaiho 10, 103–111.

Baba, K. (1949). ‘Opisthobranchia of Sagami Bay.’ (Iwanami Shoten: Tokyo, Japan.)

Baba, K. (1960). The genera Okenia, Goniodoridella and Goniodoris from Japan (Nudibranchia Goniodorididae). Publications of the Seto Marine Biological Laboratory 8, 79–83.
The genera Okenia, Goniodoridella and Goniodoris from Japan (Nudibranchia Goniodorididae).Crossref | GoogleScholarGoogle Scholar |

Behrens, D. (2001). Okenia pellucida. In ‘The Slug Site’. Available at http://slugsite.us/bow/nudwk275.htm

Bergh, L. S. R. (1874). Neue Nacktschnecken der Südsee, malacologische Untersuchungen II. Journal des Museum Godeffroy 2, 91–116.

Bergh, L. S. R. (1881). Ueber die Gattung Idalia, Leuckart. Archiv für Naturgeschichte 47, 140–181.

Bergh, L. S. R. (1902). The Danish Expedition to Siam 1899–1900. I. Gasteropoda Opisthobranchiata. Det Kongelige Danske Videnskabernes Selskabs Skrifter. 6 Raekke. Naturvidenskabelig og Matematisk Afdeling. 12, 153–218.

Bergh, R. (1907). The Opisthobranchiata of South Africa. Transactions of the Royal Society of South Africa 17, 1–144.
The Opisthobranchiata of South Africa.Crossref | GoogleScholarGoogle Scholar |

Bhave, V. J. (2009). Okenia echinata from Ratnagiri, India. In ‘Sea Slug Forum’. (Australian Museum: Sydney, NSW, Australia.) Available at http://www.seaslugforum.net/find/22982

Bhave, V. J. (2010). Okenia pellucida from Ratnagiri, India. In ‘Sea Slug Forum’. (Australian Museum: Sydney, NSW, Australia.) Available at http://www.seaslugforum.net/find/23273

Bonney, R., Phillips, T. B., Ballard, H. L., and Enck, J. W. (2016). Can citizen science enhance public understanding of science? Public Understanding of Science 25, 2–16.
Can citizen science enhance public understanding of science?Crossref | GoogleScholarGoogle Scholar | 26445860PubMed |

Bouchet, P., and Ortea, J. (1983). A new Hopkinsia feeding on bryozoa in the South Pacific (Mollusca: Opisthobranchia). Venus – Japanese Journal of Malacology 42, 227–233.

Brown, L., Finston, T., Humphreys, G., Eberhard, S., and Pinder, A. (2015). Groundwater oligochaetes show complex genetic patterns of distribution in the Pilbara region of Western Australia. Invertebrate Systematics 29, 405–420.
Groundwater oligochaetes show complex genetic patterns of distribution in the Pilbara region of Western Australia.Crossref | GoogleScholarGoogle Scholar |

Burn, R. (1967). Description of two new species of Okenia (Nudibranchia, Doridacea) from south-eastern Australia. Proceedings of the Royal Zoological Society of New South Wales 1966, 52–57.

Chuk, J. (2010). Okenia rhinorma from S.E. Australia. In ‘Sea Slug Forum’. (Australian Museum: Sydney, NSW, Australia.) Available at http://www.seaslugforum.net/find/23109

Cobb, G. (2009). Okenia rhinorma found sthn Queensland. In ‘Sea Slug Forum’. (Australian Museum: Sydney, NSW, Australia.) Available at http://www.seaslugforum.net/find/22723

Coleman, N. (2008). ‘Nudibranchs Encyclopedia: a Catalogue of Asia. Indo-Pacific Sea Slugs.’ (Neville Coleman’s Underwater Geographic: Logan, Qld, Australia.)

Coleman, N. (2015). ‘Nudibranchs Encyclopedia – Catalogue of Asia/Indo Pacific Sea Slugs.’ 2nd edn. (New Neville Coleman’s Underwater Geographic, Pty Ltd: Logan, Qld, Australia.)

Colgan, D. J., Mclauchlan, A., Wilson, G. D. F., Livingston, S., Macaranas, J., Edgecombe, G. D., Cassis, G., and Gray, M. R. (1998). Molecular phylogenetics of the Arthropoda: relationships based on histone H and U2 snRNA DNA sequences. Australian Journal of Zoology 46, 419–437.
Molecular phylogenetics of the Arthropoda: relationships based on histone H and U2 snRNA DNA sequences.Crossref | GoogleScholarGoogle Scholar |

Cranfield, H. J., Gordon, D. P., Willan, R. C., Marshall, B. A., Battershill, C. N., Francis, M. P., Nelson, W. A., Glasby, C. J., and Read, G. B. (1998). Adventive marine species in New Zealand. NIWA Technical Report 34, 1–48.

Darriba, D., Taboada, G. L., Doallo, R., and Posada, D. (2012). jModelTest 2: more models, new heuristics and parallel computing. Nature Methods 9, 772.
jModelTest 2: more models, new heuristics and parallel computing.Crossref | GoogleScholarGoogle Scholar | 22847109PubMed |

Debelius, H., and Kuiter, R. H. (2007). ‘Nudibranchs of the World.’ (Ikan-Unterwasserarchiv: Frankfurt, Germany.)

Ebach, M. C., and Holdrege, C. (2005). DNA barcoding is no substitute for taxonomy. Nature 434, 697.
DNA barcoding is no substitute for taxonomy.Crossref | GoogleScholarGoogle Scholar | 15815602PubMed |

Edmunds, M. (1966). Teshia digitata gen. and sp. nov., a dorid nudibranch from Ghana. Journal of the Malacological Society of London 37, 69–72.
Teshia digitata gen. and sp. nov., a dorid nudibranch from Ghana.Crossref | GoogleScholarGoogle Scholar |

Epstein, H. E., Hallas, J. M., Johnson, R. F., Lopez, A., and Gosliner, T. M. (2019). Reading between the lines: revealing cryptic species diversity and colour patterns in Hypselodoris nudibranchs (Mollusca: Heterobranchia: Chromodorididae). Zoological Journal of the Linnean Society 186, 116–189.
Reading between the lines: revealing cryptic species diversity and colour patterns in Hypselodoris nudibranchs (Mollusca: Heterobranchia: Chromodorididae).Crossref | GoogleScholarGoogle Scholar |

Folmer, O., Black, M., Hoeh, W., Lutz, R., and Vrijenhoek, R. (1994). DNA primers for amplification of mitochondrial cytochrome-c oxidase subunit I from diverse metazoan invertebrates. Molecular Marine Biology and Biotechnology 3, 294–299.
| 7881515PubMed |

Fraser, V. (2002). Okenia amoenula? from South Africa. In ‘Sea Slug Forum’. (Australian Museum: Sydney, NSW, Australia.) Available at http://www.seaslugforum.net/find/5842

Gadagkar, S. R., Rosenberg, M. S., and Kumar, S. (2005). Inferring species phylogenies from multiple genes: concatenated sequence tree versus consensus gene tree. Journal of Experimental Zoology – B. Molecular and Developmental Evolution 304, 64–74.
Inferring species phylogenies from multiple genes: concatenated sequence tree versus consensus gene tree.Crossref | GoogleScholarGoogle Scholar | 15593277PubMed |

Giovos, I., Kleitou, P., Poursanidis, D., Batjakas, I., Bernardi, G., Crocetta, F., Doumpas, N., Kalogirou, S., Kampouris, T. E., Keramidas, I., Langeneck, J., Maximiadi, M., Mitsou, E., Stoilas, V., Tiralongo, F., Romanidis-Kyriakidis, G., Xentidis, N., Zenetos, A., and Langeneck, J. (2019). Citizen-science for monitoring marine invasions and stimulating public engagement: a case project from the eastern Mediterranean. Biological Invasions 21, 3707–3721.
Citizen-science for monitoring marine invasions and stimulating public engagement: a case project from the eastern Mediterranean.Crossref | GoogleScholarGoogle Scholar |

Goddard, J. H. R., Gosliner, T. M., and Pearse, J. S. (2011). Impacts associated with the recent range shift of the aeolid nudibranch Phidiana hiltoni (Mollusca, Opisthobranchia) in California. Marine Biology 158, 1095–1109.
Impacts associated with the recent range shift of the aeolid nudibranch Phidiana hiltoni (Mollusca, Opisthobranchia) in California.Crossref | GoogleScholarGoogle Scholar |

Golestani, H., Crocetta, F., Padula, V., Camacho-García, Y., Langeneck, J., Poursanidis, D., Pola, M., Yokes, M. B., Cervera, J. L., Jung, D. W., Gosliner, T. M., Araya, J. F., Hooker, Y., Schrodl, M., and Valdes, A. (2019). The little Aplysia coming of age: from one species to a complex of species complexes in Aplysia parvula (Mollusca: Gastropoda: Heterobranchia). Zoological Journal of the Linnean Society 187, 279–330.
The little Aplysia coming of age: from one species to a complex of species complexes in Aplysia parvula (Mollusca: Gastropoda: Heterobranchia).Crossref | GoogleScholarGoogle Scholar |

Gosliner, T. M. (1987). ‘Nudibranchs of South Africa.’ (Sea Challengers: Monterey, CA, USA.)

Gosliner, T. M. (2004). Phylogenetic systematics of Okenia, Sakishimaia, Hopkinsiella and Hopkinsia (Nudibranchia: Goniodorididae) with descriptions of new species from the tropical Indo-Pacific. Proceedings of the California Academy of Sciences 55, 125–161.

Gosliner, T. M., Johnson, S., and Bertsch, H. (1986). Additions to the opisthobranch gastropod fauna of the Hawaii Islands. Annual Report – Western Society of Malacology 18, 14–17.

Gosliner, T. M., Valdes, A., and Behrens, D. (2015). ‘Nudibranch & Sea Slug Identification – Indo-Pacific.’ (New World Publications: Jacksonville, FL, USA.)

Gosliner, T. M., Valdes, A., and Behrens, D. (2018). ‘Nudibranch & Sea Slug Identification – Indo-Pacific.’ (New World Publications: Jacksonville, FL, USA.)

Goto, S. (2020). Okenia pellucida Burn, 1957. In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_pellucida/23059

Gray, J. E. (1850). A list of the genera of recent Mollusca, their synonyma and types. In ‘Figures of Molluscous Animals, Selected from Various Authors’. (Ed. M. E. Gray.) Vol. 4 (August). Frontispiece (portrait of Mrs. Gray), pp. ii–iv (preface), 1–62 (explanation of plates 1–312 in Volumes 1–3), pp. 63–124 (systematic arrangement of figures), pp. 127–219. (reprint of Gray 1847) (Longman, Brown, Green and Longmans: London, UK.)

Guerra-García, J. M., Espinosa Torre, F., and García Gómez, J. C. (2008). Trends in taxonomy today: an overview about the main topics in taxonomy. Zoologica Baetica 19, 15–49.

Hamatani, I. (1961). Preliminary account of a new species of Okenia from Osaka Bay, Japan (Nudibranchia – Goniodorididae). Publications of the Seto Marine Biological Laboratory 9, 363–365.
Preliminary account of a new species of Okenia from Osaka Bay, Japan (Nudibranchia – Goniodorididae).Crossref | GoogleScholarGoogle Scholar |

Hamatani, I. (2001). Two new species of Goniodorididae (Opisthobranchia; Nudibranchia) with a new genus from Kuroshima Island, Okinawa, Japan. Venus 60, 151–156.

Han-de-Beaux, S. (2015). Okenia atkinsonorum nudibranch. In ‘Sydney Dives’. Available at https://www.sydneydives.com/okeniaatkinsonorum.html

Hausdorf, B., and Hennig, C. (2020). Species delimitation and geography. Molecular Ecology Resources 20, 950–960.
Species delimitation and geography.Crossref | GoogleScholarGoogle Scholar | 32384204PubMed |

Hillis, D. M., and Bull, J. J. (1993). An empirical test of bootstrapping as a method for assessing confidence in phylogenetic analysis. Systematic Biology 42, 182–192.
An empirical test of bootstrapping as a method for assessing confidence in phylogenetic analysis.Crossref | GoogleScholarGoogle Scholar |

Imakawa, I. (2015). Okenia rhinorma Rudman, 2007. In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_rhinorma/562

Imakawa, I. (2016). Okenia rhinorma Rudman, 2007. In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_rhinorma/3214

Inkhavilay, K., Sutcharit, C., Bantaowong, U., Chanabun, R., Siriwut, W., Srisonchai, R., Pholyotha, A., Jirapatrasilp, P., and Panha, S. (2019). Annotated checklist of the terrestrial molluscs from Laos (Mollusca, Gastropoda). ZooKeys 834, 1–166.
Annotated checklist of the terrestrial molluscs from Laos (Mollusca, Gastropoda).Crossref | GoogleScholarGoogle Scholar | 31105437PubMed |

Irwin, A. (2018). No PhDs needed: how citizen science is transforming research. Nature 562, 480–482.
No PhDs needed: how citizen science is transforming research.Crossref | GoogleScholarGoogle Scholar | 30353162PubMed |

Iwakiri, A. (2018). Okenia echinata Baba, 1949. In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_echinata/9206

Iwakiri, A. (2018b). Okenia pilosa (Bouchet & Ortea, 1983). In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_pilosa/11181

Iwakiri, A. (2019). Okenia barnardi Baba, 1937. In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_barnardi/18463

Iwakiri, A. (2019b). Okenia echinata Baba, 1949. In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_echinata/15729

Johnson, N. A., Smith, C. H., Pfeiffer, J. M., Randklev, C. R., Williams, J. D., and Austin, J. D. (2018). Integrative taxonomy resolves taxonomic uncertainty for freshwater mussels being considered for protection under the US Endangered Species Act. Scientific Reports 8, 15892.
Integrative taxonomy resolves taxonomic uncertainty for freshwater mussels being considered for protection under the US Endangered Species Act.Crossref | GoogleScholarGoogle Scholar | 30367102PubMed |

Jung, D., Lee, J., and Kim, C. B. (2014). A report on five new records of nudibranch molluscs from Korea. Animal Systematics, Evolution and Diversity 30, 124–131.
A report on five new records of nudibranch molluscs from Korea.Crossref | GoogleScholarGoogle Scholar |

Kakegawa, M. (2016). Okenia rhinorma Rudman, 2007. In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_rhinorma/4036

Kakegawa, M. (2017). Okenia echinata Baba, 1949. In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_echinata/7876

Kakegawa, M. (2020). Okenia echinata Baba, 1949. In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_echinata/19927

Kamei, I. (2017). Okenia barnardi Baba, 1937. In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_barnardi/10420

Kasahara, M. (2020). Okenia japonica Baba, 1949. In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_japonica/19161

Kelnarova, I., Jendek, E., Grebennikov, V. V., and Bocak, L. (2019). First molecular phylogeny of Agrilus (Coleoptera: Buprestidae), the largest genus on Earth, with DNA barcode database for forestry pest diagnostics. Bulletin of Entomological Research 109, 200–211.
First molecular phylogeny of Agrilus (Coleoptera: Buprestidae), the largest genus on Earth, with DNA barcode database for forestry pest diagnostics.Crossref | GoogleScholarGoogle Scholar | 29784069PubMed |

Kimoto, N. (2020). Okenia sp. 5. In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_sp._5

Koh, D. B. (2003). Hopkinsia hiroi from Sth Korea. In ‘Sea Slug Forum’. (Australian Museum: Sydney, NSW, Australia.) Available at http://www.seaslugforum.net/find/9499

Koh, D. B. (2005). Okenia barnardi laying eggs in Korea. In ‘Sea Slug Forum’. (Australian Museum: Sydney, NSW, Australia.) Available at http://www.seaslugforum.net/find/12938

Koh, D. B. (2006). ‘Sea slugs of Korea.’ (Pungdeung: Korea.)

Komine, K. (2016). Okenia echinata Baba, 1949. In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_echinata/12780

Koretz, B. (2007). Okenia rhinorma from the Red Sea. In ‘Sea Slug Forum’. (Australian Museum: Sydney, NSW, Australia.) Available at http://www.seaslugforum.net/find/13354

Koruda, T. (2013). Okenia echinata Baba, 1949. In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_echinata

Kozlov, A. M., Darriba, D., Flouri, T., Morel, B., and Stamatakis, A. (2019). RAxML-NG: a fast, scalable, and user-friendly tool for maximum likelihood phylogenetic inference. Bioinformatics 35, 4455.
RAxML-NG: a fast, scalable, and user-friendly tool for maximum likelihood phylogenetic inference.Crossref | GoogleScholarGoogle Scholar | 31070718PubMed |

Kumar, S., Stecher, G., and Tamura, K. (2016). MEGA7: molecular evolutionary genetics analysis version 7.0 for bigger datasets. Molecular Biology and Evolution 33, 1870–1874.
MEGA7: molecular evolutionary genetics analysis version 7.0 for bigger datasets.Crossref | GoogleScholarGoogle Scholar | 27004904PubMed |

Kurihara, T. (2003). Re: Okenia echinata from Japan. In ‘Sea Slug Forum’. (Australian Museum: Sydney, NSW, Australia.) Available at http://www.seaslugforum.net/find/9146

Lee, K. (2011). Okenia rhinorma. In ‘The Slug Site’. Available at http://slugsite.us/bow2007/nudwk737.htm

Lemmon, A. R., Brown, J. M., Stanger-Hall, K., and Lemmon, E. M. (2009). The effect of ambiguous data on phylogenetic estimates obtained by maximum likelihood and Bayesian inference. Systematic Biology 58, 130–145.
The effect of ambiguous data on phylogenetic estimates obtained by maximum likelihood and Bayesian inference.Crossref | GoogleScholarGoogle Scholar | 20525573PubMed |

Leuckart, F. S. (1828). ‘Breves Animalium Quorundum Maxima ex Parte Marinorum Descriptiones.’ (Heidelberg, Germany.)

MacFarland, F. M. (1905). A preliminary account of the Dorididae of Monterey Bay, California. Proceedings of the Biological Society of Washington 18, 35–54.

Macnae, W. (1958). The families Polyceridae and Goniodorididae (Mollusca, Nudibranchiata) in southern Africa. Transactions of the Royal Society of South Africa 35, 341–372.
The families Polyceridae and Goniodorididae (Mollusca, Nudibranchiata) in southern Africa.Crossref | GoogleScholarGoogle Scholar |

Marshall, J. G., and Willan, R. C. (1999). ‘Nudibranchs of Heron Island, Great Barrier Reef. A survey of the Opisthobranchia (Sea Slugs) of Heron and Wistari Reefs.’ (Backhuys Publishers: Leiden, Netherlands.)

McCaffrey, K. (2020). Okenia pellucida Burn, 1967. In ‘Sea Slugs of Hawaii’. Available at http://seaslugsofhawaii.com/species/Okenia-pellucida-b.html

Mikkelsen, N. T., Todt, C., Kocot, K. M., Halanych, K. M., and Willassen, E. (2019). Molecular phylogeny of Caudofoveata (Mollusca) challenges traditional views. Molecular Phylogenetics and Evolution 132, 138–150.
Molecular phylogeny of Caudofoveata (Mollusca) challenges traditional views.Crossref | GoogleScholarGoogle Scholar | 30423439PubMed |

Miller, M. A., Pfeiffer, W., and Schwartz, T. (2010). Creating the CIPRES Science Gateway for inference of large phylogenetic trees. In ‘Proceedings of the Gateway Computing Environments Workshop (GCE)’, 14 November 2010, New Orleans, LA, USA. INSPEC Accession Number 11705685. (IEEE.) 10.1109/GCE.2010.5676129

Mirarab, S., Bayzid, M. S., and Warnow, T. (2016). Evaluating summary methods for multilocus species tree estimation in the presence of incomplete lineage sorting. Systematic Biology 65, 366–380.
Evaluating summary methods for multilocus species tree estimation in the presence of incomplete lineage sorting.Crossref | GoogleScholarGoogle Scholar | 25164915PubMed |

Mizutani, K. (2018). Okenia rhinorma Rudman, 2007. In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_rhinorma/8478

MolluscaBase (2021). Okenia Menke, 1830. In ‘MolluscaBase’. (World Register of Marine Species.) Available at http://www.marinespecies.org/aphia.php?p=taxdetails&id=138042 [Verified 26 February 2021].

Morton, J. E., and Miller, M. C. (1968). ‘The New Zealand Seashore.’ (Collins: London and Auckland.)

Mouri, Y. (2018). Okenia echinata Baba, 1949. In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_echinata/9321

Nabhan, A. R., and Sarkar, I. N. (2012). The impact of taxon sampling on phylogenetic inference: a review of two decades of controversy. Briefings in Bioinformatics 13, 122–134.
The impact of taxon sampling on phylogenetic inference: a review of two decades of controversy.Crossref | GoogleScholarGoogle Scholar | 21436145PubMed |

Nakano, R. (2004). ‘Nudibranchs of Japan Islands.’ (Rutles: Tokyo, Japan.)

Nakano, R. (2018). ‘Field Guide to Sea Slugs and Nudibranchs of Japan.’ (Bun-ichi Co., Ltd: Tokyo, Japan.)

Nimbs, M. J., and Smith, S. D. (2016). An illustrated inventory of the sea slugs of New South Wales, Australia (Gastropoda: Heterobranchia). Proceedings of the Royal Society of Victoria 128, 44–113.
An illustrated inventory of the sea slugs of New South Wales, Australia (Gastropoda: Heterobranchia).Crossref | GoogleScholarGoogle Scholar |

Nishina, M. (2001). Okenia japonica from of Hachijo Is, Japan. In ‘Sea Slug Forum’. (Australian Museum: Sydney, NSW, Australia.) Available at http://www.seaslugforum.net/find/4947

Nissie (2006). Okenia barnardi Baba, 1937. In ‘Nissie’. Available at http://nissiesphotoalbums.web.fc2.com/doris/ibaraumiushi.html

Nobuhiko, K. (2018). Okenia hiroi (Baba, 1938). In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_hiroi/9107

Nobuhiko, K. (2018b). Okenia pilosa (Bouchet & Ortea, 1983). In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_pilosa/9112

Norman, A. M. (1890). Revision of British Mollusca. Annals & Magazine of Natural History 6, 60–91.
Revision of British Mollusca.Crossref | GoogleScholarGoogle Scholar |

Odhner, N. J. (1941). New polycerid nudibranchiate mollusca and remarks on this family. Göteborgs Kungl. Vetenskaps- och Vitterhets-Samhälles Handlingar, Ser. B, Matematiska och Naturvetenskapliga Skrifter 1, 1–20.

Ogura, S. (2017). Okenia echinata Baba, 1949. In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_echinata/9513

Oue, T. (2019). Okenia japonica Baba, 1949. In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_japonica/20846

Palumbi, S. R. (1996). Nucleic acids II: the polymerase chain reaction. In ‘Molecular Systematics’. (Eds D. M. Hillis, C. Moritz, and B. K. Mable.) pp. 205–247. (Sinauer & Associates Inc: Sunderland, MA, USA.)

Paz-Sedano, S., Ortigosa, D., and Pola, M. (2017). A new Okenia Menke, 1830 from the Azores Islands, Portugal (Mollusca, Nudibranchia, Goniodorididae). Spixiana 40, 13–22.

Pellet, F., and Pellet, P. (2007). Okenia pellucida from Lembeh, north Sulawesi. In ‘Sea Slug Forum’. (Australian Museum: Sydney, NSW, Australia.) Available at http://www.seaslugforum.net/find/19476

Picton, B. (2002). Okenia barnardi from Hong Kong. In ‘Sea Slug Forum’. (Australian Museum: Sydney, NSW, Australia.) Available at http://www.seaslugforum.net/find/5961

Pires, A. C., and Marinoni, L. (2010). DNA barcoding and traditional taxonomy unified through Integrative Taxonomy: a view that challenges the debate questioning both methodologies. Biota Neotropica 10, 339–346.
DNA barcoding and traditional taxonomy unified through Integrative Taxonomy: a view that challenges the debate questioning both methodologies.Crossref | GoogleScholarGoogle Scholar |

Pola, M., Roldan, P., and Padilla, S. (2014). Molecular data on the genus Okenia (Nudibranchia: Goniodorididae) reveal a new cryptic species from New South Wales (Australia). Journal of the Marine Biological Association of the United Kingdom 94, 587–598.
Molecular data on the genus Okenia (Nudibranchia: Goniodorididae) reveal a new cryptic species from New South Wales (Australia).Crossref | GoogleScholarGoogle Scholar |

Pola, M., Paz-Sedano, S., Macali, A., Minchin, D., Marchini, A., Vitale, F., Licchelli, C., and Crocetta, F. (2019). What is really out there? Review of the genus Okenia Menke, 1830 (Nudibranchia: Goniodorididae) in the Mediterranean Sea with description of two new species. PLoS One 14, e0215037.
What is really out there? Review of the genus Okenia Menke, 1830 (Nudibranchia: Goniodorididae) in the Mediterranean Sea with description of two new species.Crossref | GoogleScholarGoogle Scholar | 31042722PubMed |

Puillandre, N., Lambert, A., Brouillet, S., and Achaz, G. (2012a). ABGD, Automatic Barcode Gap Discovery for primary species delimitation. Molecular Ecology 21, 1864–1877.
ABGD, Automatic Barcode Gap Discovery for primary species delimitation.Crossref | GoogleScholarGoogle Scholar | 21883587PubMed |

Puillandre, N., Modica, M. V., Zhang, Y., Sirovich, L., Boisselier, M. C., Cruaud, C., Holford, M., and Samadi, S. (2012b). Large‐scale species delimitation method for hyperdiverse groups. Molecular Ecology 21, 2671–2691.
Large‐scale species delimitation method for hyperdiverse groups.Crossref | GoogleScholarGoogle Scholar | 22494453PubMed |

Puillandre, N., Bouchet, P., Duda, T. F., Kauferstein, S., Kohn, A. J., Olivera, B. M., Watkins, C., and Meyer, C. (2014). Molecular phylogeny and evolution of the cone snails (Gastropoda, Conoidea). Molecular Phylogenetics and Evolution 78, 290–303.
Molecular phylogeny and evolution of the cone snails (Gastropoda, Conoidea).Crossref | GoogleScholarGoogle Scholar |

Rauch, C., and Malaquias, M. A. E. (2019). Sea slugs of southern Norway – an example of citizens contributing to science. The Malacologist 73, 23–27.

Riek, D. W. (2004). Okenia echinata? from northern N.S.W. In ‘Sea Slug Forum’. (Australian Museum: Sydney, NSW, Australia.) Available at http://www.seaslugforum.net/find/12814

Ross, K. G., Gotzek, D., Ascunce, M. S., and Shoemaker, D. D. (2010). Species delimitation: a case study in a problematic ant taxon. Systematic Biology 59, 162–184.
Species delimitation: a case study in a problematic ant taxon.Crossref | GoogleScholarGoogle Scholar | 20525628PubMed |

Rudman, W. B. (2004). Further species of the opisthobranch genus Okenia (Nudibranchia: Goniodorididae) from the Indo-West Pacific. Zootaxa 695, 1–70.
Further species of the opisthobranch genus Okenia (Nudibranchia: Goniodorididae) from the Indo-West Pacific.Crossref | GoogleScholarGoogle Scholar |

Rudman, W. B. (2007). Two new species of Okenia (Gastropoda: Nudibranchia: Goniodorididae) from eastern Australia and Tanzania. Zootaxa 1657, 57–67.
Two new species of Okenia (Gastropoda: Nudibranchia: Goniodorididae) from eastern Australia and Tanzania.Crossref | GoogleScholarGoogle Scholar |

Rudman, W. B., and Avern, G. (1988). Molluscan dentistry – the tales that teeth tell. Australian Natural History 22, 388–393.

Rudman, W. B., and Darvell, B. W. (1990). Opisthobranch molluscs of Hong Kong. Part I. Asian Marine Biology 7, 31–79.

Rudman, W. B., and Darvell, B. W. (2001). Okenia japonica from Hong Kong. In ‘Sea Slug Forum’. (Australian Museum: Sydney, NSW, Australia.) Available at http://www.seaslugforum.net/find/5070

Sales, L., Migotto, A. E., Baroni, S., and Cunha, C. M. (2019). Taxonomic reassessment and redescription of Okenia polycerelloides (Ortea & Bouchet, 1983) (Nudibranchia: Goniodorididae) based on morphological and molecular data. Marine Biodiversity 49, 2351–2368.
Taxonomic reassessment and redescription of Okenia polycerelloides (Ortea & Bouchet, 1983) (Nudibranchia: Goniodorididae) based on morphological and molecular data.Crossref | GoogleScholarGoogle Scholar |

Schlick‐Steiner, B. C., Arthofer, W., and Steiner, F. M. (2014). Take up the challenge! Opportunities for evolution research from resolving conflict in integrative taxonomy. Molecular Ecology 23, 4192–4194.
Take up the challenge! Opportunities for evolution research from resolving conflict in integrative taxonomy.Crossref | GoogleScholarGoogle Scholar | 25155716PubMed |

Schwarz, G. (1978). Estimating the dimension of a model. Annals of Statistics 6, 461–464.
Estimating the dimension of a model.Crossref | GoogleScholarGoogle Scholar |

Shinya, R. (2020). Okenia pellucida Burn, 1957. In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_pellucida

Skipworth, I. R. (2007). Okenia atkinsonorum? from New Zealand. In ‘Sea Slug Forum’. (Australian Museum: Sydney, NSW, Australia.) Available at http://www.seaslugforum.net/find/21216

Sokai, Y. (2014). Okenia hiroi (Baba, 1938). In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_hiroi/1604

Song, X. K., Qing, J., Ke, C. H., and Li, F. X. (2009). New records of two Nudibranchia species in coastal waters of China. Journal of Oceanography in Taiwan Straits 28, 1–6.

Stender, K. (2018). Family Goniodorididae EAST ASIA Okenia hiroi. In ‘MarinelifePhotography.com Keoki & Yuko Stender’. Available at https://www.marinelifephotography.com/marine/mollusks/slugs/okenia-hiroi.htm

Su, Y., Huang, L. J., Chang, Y. W., and Mok, H. K. (2009). Temporal changes in nudibranch composition at a coastal site off Penghu (the Pescadores) in the Taiwan Strait. Zoological Studies 48, 448–459.

Tanonaka, S. (2020). Okenia hiroi (Baba, 1938). In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_hiroi/22740

Thollesson, M. (2000). Increasing fidelity in parsimony analysis of dorid nudibranchs by differential weighting, or a tale of two genes. Molecular Phylogenetics and Evolution 16, 161–172.
Increasing fidelity in parsimony analysis of dorid nudibranchs by differential weighting, or a tale of two genes.Crossref | GoogleScholarGoogle Scholar | 10942604PubMed |

Tibiriçá, Y., and Malaquias, M. A. E. (2017). The bubble snails (Gastropoda, Heterobranchia) of Mozambique: an overlooked biodiversity hotspot. Marine Biodiversity 47, 791–811.
The bubble snails (Gastropoda, Heterobranchia) of Mozambique: an overlooked biodiversity hotspot.Crossref | GoogleScholarGoogle Scholar |

Tibiriçá, Y., Pola, M., and Cervera, J. L. (2017). Astonishing diversity revealed: an annotated and illustrated inventory of Nudipleura (Gastropoda: Heterobranchia) from Mozambique. Zootaxa 4359, 1–133.
Astonishing diversity revealed: an annotated and illustrated inventory of Nudipleura (Gastropoda: Heterobranchia) from Mozambique.Crossref | GoogleScholarGoogle Scholar | 29245453PubMed |

Tillen, G. (2011). Okenia rhinorma Rudman, 2007. In ‘Sea-Slugs from the Philippine Islands’. Available at https://www.philippine-sea-slugs.com/Nudibranchia/Doridina/Okenia_rhinorma_01.html

Toms, J. A., Pola, M., von der Heyden, S., and Gosliner, T. M. (2021). Disentangling species of the genus Limacia OF Müller, 1781, from southern Africa and Europe using integrative taxonomical methods, with the description of four new species. Marine Biodiversity 51, 1–31.
Disentangling species of the genus Limacia OF Müller, 1781, from southern Africa and Europe using integrative taxonomical methods, with the description of four new species.Crossref | GoogleScholarGoogle Scholar |

Van Belle, D. (2003). Thecacera from Lembeh. In ‘Sea Slug Forum’. (Australian Museum: Sydney, NSW, Australia.) Available at http://www.seaslugforum.net/find/8751

Vinarski, M. V., Aksenova, O. V., Bespalaya, Y. V., Kondakov, A. V., Tomilova, A. A., Khrebtova, I. S., Gofarov, M. Y., and Bolotov, I. N. (2021). One Beringian genus less: a re‐assesment of Pacifimyxas Kruglov & Starobogatov, 1985 (Mollusca: Gastropoda: Lymnaeidae) questions the current estimates of Beringian biodiversity. Journal of Zoological Systematics and Evolutionary Research 59, 44–59.
One Beringian genus less: a re‐assesment of Pacifimyxas Kruglov & Starobogatov, 1985 (Mollusca: Gastropoda: Lymnaeidae) questions the current estimates of Beringian biodiversity.Crossref | GoogleScholarGoogle Scholar |

Vogel, R. M., and Schultz, L. P. (1970). Cargoa cupella, new genus and new species of nudibranch from Chesapeake Bay and the generic status of Okenia Menke, Idalia Leuckart and Idalla Örsted. The Veliger 12, 388–393.

Waterton, C. (2017). ‘Barcoding Nature: Shifting Cultures of Taxonomy in an Age of Biodiversity Loss.’ (Routledge.)

Willan, R. C., and Coleman, N. (1984). ‘Nudibranchs of Australasia.’ (Australasian Marine Photographic Index: Sydney, NSW, Australia.)

Yeates, D., Seago, A., Nelson, L., Cameron, S. L., Joseph, L., and Trueman, J. W. H. (2011). Integrative taxonomy, or iterative taxonomy? Systematic Entomology 36, 209–217.
Integrative taxonomy, or iterative taxonomy?Crossref | GoogleScholarGoogle Scholar |

Yumi, I. (2017). Okenia hiroi (Baba, 1938). In ‘Nudibranchs in the World’. Available at https://en.seaslug.world/species/okenia_hiroi/20750

Zhang, J., Kapli, P., Pavlidis, P., and Stamatakis, A. (2013). A general species delimitation method with applications to phylogenetic placements. Bioinformatics 29, 2869–2876.
A general species delimitation method with applications to phylogenetic placements.Crossref | GoogleScholarGoogle Scholar | 23990417PubMed |

Zheng, C., Ye, Z., Zhu, X., Zhang, H., Dong, X., Chen, P., and Bu, W. (2020). Integrative taxonomy uncovers hidden species diversity in the rheophilic genus Potamometra (Hemiptera: Gerridae). Zoologica Scripta 49, 174–186.
Integrative taxonomy uncovers hidden species diversity in the rheophilic genus Potamometra (Hemiptera: Gerridae).Crossref | GoogleScholarGoogle Scholar |

Zou, S., Fei, C., Song, J., Bao, Y., He, M., and Wang, C. (2016). Combining and comparing coalescent, distance and character-based approaches for barcoding microalgaes: a test with Chlorella-like species (Chlorophyta). PLoS One 11, e0153833.
Combining and comparing coalescent, distance and character-based approaches for barcoding microalgaes: a test with Chlorella-like species (Chlorophyta).Crossref | GoogleScholarGoogle Scholar | 27092945PubMed |