Skip to main content
SpringerLink
Log in

Diexanthema hakuhomaruae sp. nov. (Copepoda: Siphonostomatoida: Nicothoidae) from the Hadal Zone in the Northwestern Pacific, with an 18S Molecular Phylogeny

  • Original Paper
  • Published:
Acta Parasitologica Aims and scope Submit manuscript

Abstract

Purpose

Diexanthema copepods are ectoparasites on deep-sea isopods. This genus currently contains six species, all reported from the North Atlantic. Our study describes a new species of Diexanthema found on isopods from 7184 to 7186 m depth in the Kuril-Kamchatka Trench, northwestern Pacific.

Methods

We observed the copepod’s morphology, made camera-lucida drawings, and compared our species with congeners. We determined partial sequences for its 16S rRNA and 18S rRNA genes and constructed an 18S-based maximum-likelihood copepod tree to place it phylogenetically. We identified the host isopod species through morphology and cytochrome c oxidase subunit I (COI, cox1) and 18S sequences.

Results/Conclusion

We described the copepod as Diexanthema hakuhomaruae sp. nov. and identified its host as Eugerdella cf. kurabyssalis Golovan, 2015 (Desmosomatidae). This is the first Diexanthema copepod from the Pacific and also from hadal depths. Diexanthema hakuhomaruae most closely resembles D. bathydiaita Richie, 1975, parasitic on Nannoniscus sp. (Nannoniscidae) in the Atlantic, but differs from the latter in having a smooth body surface and leg 5 in the ventrolateral region of the urosome. In the 18S tree, D. hakuhomaruae was the sister group to the Rhizorhina clade, which is consistent with the morphology-based hypothesis that they are closely related.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3

Similar content being viewed by others

Data Availability

The raw data (sampling locality; sampling date; museum deposition numbers, INSD accession numbers, and the depository for specimens) are included in the manuscript.

References

  1. Walter TC, Boxshall G (2023) Nicothoidae Dana, 1852–1853. https://www.marinespecies.org/aphia.php?p=taxdetails&id=135530. Accessed 13 Mar 2023

  2. Boxshall GA, Halsey SH (2004) An introduction to copepod diversity. The Ray Society, London

    Google Scholar 

  3. Kakui K (2016) Descriptions of two new species of Rhizorhina Hansen, 1892 (Copepoda: Siphonostomatoida: Nicothoidae) parasitic on tanaidacean crustaceans, with a note on their phylogenetic position. Syst Parasitol 93:57–68. https://doi.org/10.1007/s11230-015-9604-x

    Article  PubMed  Google Scholar 

  4. Kakui K, Munakata M (2023) A new Sphaeronella species (Copepoda: Siphonostomatoida: Nicothoidae) parasitic on Euphilomedes sp. (Ostracoda: Myodocopa: Philomedidae) from Hokkaido, Japan, with an 18S molecular phylogeny. Syst Parasitol 100:121–131. https://doi.org/10.1007/s11230-022-10075-z

    Article  Google Scholar 

  5. Ohtsuka S, Boxshall GA, Harada S (2005) A new genus and species of nicothoid copepod (Crustacea: Copepoda: Siphonostomatoida) parasitic on the mysid Siriella okadai Ii from off Japan. Syst Parasitol 62:65–81. https://doi.org/10.1007/s11230-005-5483-x

    Article  PubMed  Google Scholar 

  6. Bamber RN, Boxshall GA (2006) A new genus and species of the Langitanainae (Crustacea: Peracarida: Tanaidacea: Tanaidae) bearing a new genus and species of nicothoid parasite (Crustacea: Copepoda: Siphonostomatoida: Nicothoidae) from the New Caledonia slope. Spec Divers 11:137–148. https://doi.org/10.12782/specdiv.11.137

    Article  Google Scholar 

  7. Boyko CB (2009) Nomenclatural issues with Paranicothoe Carton, 1970 and Pseudonicothoe Avdeev & Avdeev, 1978 (Crustacea: Copepoda: Nicothoidae), with comments on the female isopod type specimen of Paranicothoe cladocera Carton, 1970. Proc Biol Soc Wash 122:206–211. https://doi.org/10.2988/08-49.1

    Article  Google Scholar 

  8. Ritchie L (1975) A new genus and two new species of Choniostomatidae (Copepoda) parasitic on two deep sea isopods. Zool J Linn Soc 57:155–178. https://doi.org/10.1111/j.1096-3642.1975.tb01415.x

    Article  Google Scholar 

  9. Boxshall GA, Harrison K (1988) New nicothoid copepods (Copepoda: Siphonostomatoida) from an amphipod and from deep-sea isopods. Bull Br Mus Nat Hist (Zool) 54:285–299

    Google Scholar 

  10. Boxshall GA, Lincoln RJ (1983) Some new parasitic copepods (Siphonostomatoida: Nicothoidae) from deep-sea asellote isopods. J Nat Hist 17:891–900. https://doi.org/10.1080/00222938300770701

    Article  Google Scholar 

  11. Akiyama T, Shimomura M, Nakamura K (2008) Collection of deep-sea small arthropods: gears for collection and processing of samples on deck. TAXA 24:27–32. https://doi.org/10.19004/taxa.24.0_27. (in Japanese with English abstract)

    Article  Google Scholar 

  12. Folmer O, Black M, Hoeh W, Lutz R, Vrijenhoek R (1994) DNA primers for amplification of mitochondrial cytochrome c oxidase subunit I from diverse metazoan invertebrates. Mol Mar Biol Biotechnol 3:294–299

    CAS  PubMed  Google Scholar 

  13. Nakayama T, Watanabe S, Mitsui K, Uchida H, Inouye I (1996) The phylogenetic relationship between the Chlamydomonadales and Chlorococcales inferred from 18SrDNA sequence data. Phycol Res 44:47–55. https://doi.org/10.1111/j.1440-1835.1996.tb00037.x

    Article  CAS  Google Scholar 

  14. Kakui K, Katoh T, Hiruta SF, Kobayashi N, Kajihara H (2011) Molecular systematics of Tanaidacea (Crustacea: Peracarida) based on 18S sequence data, with an amendment of suborder/superfamily-level classification. Zool Sci 28:749–757. https://doi.org/10.2108/zsj.28.749

    Article  Google Scholar 

  15. Kakui K, Fukuchi J, Shimada D (2021) First report of marine horsehair worms (Nematomorpha: Nectonema) parasitic in isopod crustaceans. Parasitol Res 120:2357–2362. https://doi.org/10.1007/s00436-021-07213-9

    Article  PubMed  Google Scholar 

  16. Munakata M, Tanaka H, Kakui K (2021) Heterocypris spadix sp. nov. (Crustacea: Ostracoda: Cypridoidea) from Japan, with information on its reproductive mode. Zool Sci 38:287–296. https://doi.org/10.2108/zs200127

    Article  Google Scholar 

  17. Okamoto N, Kakui K (2022) Integrative taxonomy of Zeuxo (Crustacea: Peracarida: Tanaidacea) from Japan, with the description of a new species. Biologia 77:2497–2506. https://doi.org/10.1007/s11756-022-01121-8

    Article  CAS  Google Scholar 

  18. Kumar S, Stecher G, Tamura K (2016) MEGA7: molecular evolutionary genetics analysis version 7.0 for bigger datasets. Mol Biol Evol 33:1870–1874. https://doi.org/10.1093/molbev/msw054

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  19. Munakata M, Tanaka H, Kakui K (2022) Taxonomy and natural history of Cavernocypris hokkaiensis sp. nov., the first ostracod reported from alpine streams in Japan. Zoosyst Evol 98:117–127. https://doi.org/10.3897/zse.98.80442

    Article  Google Scholar 

  20. Kakui K, Shimada D (2022) Dive into the sea: first molecular phylogenetic evidence of host expansion from terrestrial/freshwater to marine organisms in Mermithidae (Nematoda: Mermithida). J Helminthol 96:e33. https://doi.org/10.1017/S0022149X22000256

    Article  CAS  PubMed  Google Scholar 

  21. Golovan OA (2015) Description of two ubiquitous species of Desmosomatidae (Isopoda: Asellota) from the Northwest Pacific Basin east of the Kuril-Kamchatka Trench. Zootaxa 4039:201–224. https://doi.org/10.11646/zootaxa.4039.2.1

    Article  PubMed  Google Scholar 

  22. Jennings RM, Golovan O, Brix S (2020) Integrative species delimitation of desmosomatid and nannoniscid isopods from the Kuril-Kamchatka trench, with description of a hadal species. Prog Oceanogr 182:102236. https://doi.org/10.1016/j.pocean.2019.102236

    Article  Google Scholar 

  23. Altschul SF, Gish W, Miller W, Myers EW, Lipman DJ (1990) Basic local alignment search tool. J Mol Biol 215:403–410. https://doi.org/10.1016/S0022-2836(05)80360-2

    Article  CAS  PubMed  Google Scholar 

  24. Dippenaar SM (2009) Estimated molecular phylogenetic relationships of six siphonostomatoid families (Copepoda) symbiotic on elasmobranchs. Crustaceana 82:1547–1567. https://doi.org/10.1163/001121609X12511103974538

    Article  Google Scholar 

  25. DDBJ (2022) DNA Data Bank Japan. https://www.ddbj.nig.ac.jp/ Accessed 29 Nov 2022

  26. Summers MM, Al-Hakim II, Rouse GW (2014) Turbo-taxonomy: 21 new species of Myzostomida (Annelida). Zootaxa 3873:301–344. https://doi.org/10.11646/zootaxa.3873.4.1

  27. Butcher BA, Smith MA, Sharkey MJ, Quicke DLJ (2012) A turbo-taxonomic study of Thai Aleiodes (Aleiodes) and Aleiodes (Arcaleiodes) (Hymenoptera: Braconidae: Rogadinae) based largely on COI barcoded specimens, with rapid descriptions of 179 new species. Zootaxa 3457:1–232. https://doi.org/10.11646/zootaxa.3457.1.1

    Article  Google Scholar 

Download references

Acknowledgements

We thank Shigeaki Kojima and Yasunori Kano for the opportunity to join R/V Hakuho-maru cruise KH-22-8, conducted as a part of the project “Comprehensive study of diversity and evolutionary mechanisms of deep-sea animals in trenches in the northwestern Pacific” supported by KAKENHI grant (JP19H00999) from the Japan Society for the Promotion of Science (JSPS); Captain Kazuhiko Kasuga and the crew of R/V Hakuho-maru, technicians from Marine Work Japan and MOL Marine & Engineering, and researchers aboard for support in collecting; Hiroshi Kajihara, Jamael Abato, and Tsuyoshi Takano for help in sorting samples; and Matthew H. Dick for reviewing the manuscript and editing the English. This study was supported in part by Atmosphere and Ocean Research Institute, The University of Tokyo, and by KAKENHI grants (JP19K06800 and JP22H02681) from JSPS.

Funding

This study was supported in part by the Atmosphere and Ocean Research Institute, The University of Tokyo, and by KAKENHI grants (JP19K06800 and JP22H02681) from the Japan Society for Promotion of Science (JSPS). The funding agencies had no role in the study design, data collection, analysis, decision to publish, or preparation of the manuscript.

Author information

Authors and Affiliations

  1. Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan

    Keiichi Kakui

  2. Seto Marine Biological Laboratory, Kyoto University, Nishimuro, Japan

    Jun Fukuchi

  3. Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan

    Mizuki Ohta

Authors
  1. Keiichi Kakui
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Jun Fukuchi
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Mizuki Ohta
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

KK conceived and designed the study, made morphological observations on the copepods, and conducted the molecular analysis; MO made morphological observations on the isopods; KK, JF, and MO collected samples, wrote the manuscript, and read and approved the final draft.

Corresponding author

Correspondence to Keiichi Kakui.

Ethics declarations

Conflict of interest

The authors have no competing interests to declare that are relevant to the content of this article.

Ethical Approval

Not applicable.

Consent to Participate

Not applicable.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

This article is registered in ZooBank under https://zoobank.org/4A75D879-2540-46A8-AF47-97C424A48B63.

Supplementary Information

Below is the link to the electronic supplementary material.

11686_2023_676_MOESM1_ESM.fas

Supplementary file1 Aligned 18S sequences used in the maximum-likelihood analysis, with alignment-ambiguous sites retained (FAS 89 KB)

11686_2023_676_MOESM2_ESM.fas

Supplementary file2 Aligned 18S sequences used in the maximum-likelihood analysis, reduced to 1528 positions by removing alignment-ambiguous sites (FAS 78 KB)

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Kakui, K., Fukuchi, J. & Ohta, M. Diexanthema hakuhomaruae sp. nov. (Copepoda: Siphonostomatoida: Nicothoidae) from the Hadal Zone in the Northwestern Pacific, with an 18S Molecular Phylogeny. Acta Parasit. 68, 413–419 (2023). https://doi.org/10.1007/s11686-023-00676-z

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11686-023-00676-z

Keywords

Search

Navigation