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The family Ascothoracidae Grygier, 1987, a review with descriptions of new abyssal taxa parasitizing ophiuroids and remarks on the invalidity of the genus Parascothorax Wagin, 1964 (Crustacea: Thecostraca: Ascothoracida)


Two new ascothoracidan species in the family Ascothoracidae Grygier, 1987, Ascothorax rybakovi sp. nov. and Cardiosaccus pedri gen. et sp. nov., are described from the Kuril-Kamchatka Trench at abyssal depths of 5150–5700 m. They are among the deepest known ascothoracidans. They live as mesoparasites in permanent cysts within the bursae of the brittle stars Ophiacantha pacifica Lütken and Mortensen, 1899 and Amphiophiura pacifica Litvinova, 1971, respectively. This is the first study of new forms of Ascothoracidae in which SEM has been used in the descriptions, including the lattice organs and the early nauplius. Cardiosaccus differs from Ascothorax in displaying the following apomorphic traits: (i) absence of thoracopod 1; (ii) a smaller fifth antennular segment that is completely fused with the claw; (iii) absence of small setae at the base of this claw; and (iv) an extremely large ventral protrusion of the fourth abdominal segment. Material of Parascothorax synagogoides Wagin, 1964 from near the type locality, studied with SEM, could not be distinguished from Ascothorax by any reliable morphological criteria. Cyst structure and the manner of cyst formation cannot be used, because although cyst is the result of the parasites activity, this is a feature of the host, not something inherent to the parasite. Moreover, the inferred settlement of the larvae of P. synagogoides on the outer edge of the bursal slit is best regarded as plesiomorphic behavior, reflecting how the Ascothoracidae became bursal mesoparasites in the first place. We therefore regard Parascothorax as invalid and refer P. synagogoides to Ascothorax. Within the family Ascothoracidae as now constituted, Ascothorax is cosmopolitan and speciose and includes species that exclusively infect a single host species, whereas Cardiosaccus is monotypic and restricted to the northwest Pacific. Ascothorax rybakovi sp. nov. is the third species of this genus known to harbor hyperparasitic cryptoniscid isopods.

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  1. Bell FJ (1902) Reports on the collections of Natural History made in the Antarctic regions during the voyage of the “Southern Cross”. VIII. Echinoderma 214–220, 2 pl

  2. Berndt W (1907) Über das system der Acrothoracica. Archiv für Naturgeschichte 73:287–289

    Google Scholar 

  3. de Lacaze-Duthiers H (1865) Mémoire sur un mode nouveau de parasitisme observé sur un animal non décrit. CR Acad Sci Paris 61:838–841

  4. Djakonov AM (1914) Ascothorax ophioctenis n.g. und n.sp., ein neuer Endoparasit aus der Gruppe der Ascothoracidae. Trudy imperatorskogo Sankt-Peterburgskogo Obshchestva Estestestvoispytateley 45(4):158–165 (in Russian with German summary)

    Google Scholar 

  5. Forbes E (1852) Echinodermata of the British Tertiaries, 1–36, pls 1–4. Palaeontographical Society, London

    Google Scholar 

  6. Gruvel A (1905) Monographie des Cirrhipèdes our Thécostracés. Masson and Cie, Paris 666 pp

  7. Grygier MJ (1981a) Gorgoniscus incisodactylus, a new isopod of the epicaridean superfamily Cryptoniscoidea, parasitic on an ascothoracican cirriped from Hawaii. Proc Biol Soc Wash 94:122–134

    Google Scholar 

  8. Grygier MJ (1981b) Gorgonolaureus muzikae sp. nov. (Crustacea: Ascothoracida) parasitic on a Hawaiian gorgonian, with special reference to its protandric hermaphroditism. J Nat Hist 15:1019–1045

    Article  Google Scholar 

  9. Grygier MJ (1983a) Ascothorax, a review with descriptions of new species and remarks on larval development, biogeography, and ecology (Crustacea: Ascothoracida). Sarsia 68:103–126

    Article  Google Scholar 

  10. Grygier MJ (1983b) Revision of Synagoga (Crustacea: Maxillopoda: Ascothoracida). J Nat Hist 17:213–239

    Article  Google Scholar 

  11. Grygier MJ (1983c) Ctenosculum hawaiiense Heath: confirmation of its affinities (Crustacea: Ascothoracida - ex Mollusca: Gastropoda). J Crustac Biol 3(2):257–265

    Article  Google Scholar 

  12. Grygier MJ (1984) Ascothoracida (Crustacea: Maxillopoda) parasitic on Chrysogorgia (Gorgonacea) in the Pacific and Western Atlantic. Bull Mar Sci 34(1):141–169

    Google Scholar 

  13. Grygier MJ (1985) Lauridae: taxonomy and morphology of ascothoracid crustacean parasites of zoanthids. Bull Mar Sci 36:278–303

    Google Scholar 

  14. Grygier MJ (1987a) Classification of the Ascothoracida (Crustacea). Proc Biol Soc Wash 100(3):452–458

    Google Scholar 

  15. Grygier MJ (1987b) Nauplii, antennular ontogeny, and the position of the Ascothoracida within the Maxillopoda. Joournal of Crustacean Biology 7:87–104

    Article  Google Scholar 

  16. Grygier MJ (1990) Five new species of bathyal Atlantic Ascothoracida (Crustacea: Maxillopoda) from the equator to 50°N latitude. Bull Mar Sci 46:655–676

    Google Scholar 

  17. Grygier MJ (1991) Redescription, ontogeny, and demography of Parascothorax synagogoides (Crustacea: Ascothoracida) parasitic on Ophiopthalmus normani (Ophiuroidea) in the bathyal basins off Southern California. Proceedings of theSan Diego Society of Natural History 6:1–20

  18. Grygier MJ, Fratt DB (1984) The ascothoracid crustacean Ascothorax gigas: redescription, larval development, and notes on its infestation of the Antarctic ophiuroid Ophionotus victoriae. Biology of the Antarctic Seas XVI, Antarct Res Ser 41(2):43–58

  19. Heegaard P (1951) Antarctic parasitic copepods and ascothoracid cirriped from brittle-stars. Videnskabelige Meddelelser Dansk Naturhistorisk Forening 113:171190

  20. Høeg JT, Chan BKK, Kolbasov GA, Grygier MJ (2014) Ascothoracida. In: Martin J, Olesen J, Høeg JT (eds) Atlas of crustacean larvae. Johns Hopkins University Press, Baltimore, pp 104–106

    Google Scholar 

  21. Koehler R (1900) Note preliminaire sur les Echinides et les Ophiures de l'Expédition Antarctique Belge. Bull Acad Roy Belgique 11(3):814–820

  22. Kolbasov GA, Newman WA (2018) A new species of Synagoga (Crustacea: Thecostraca: Ascothoracida) parasitic on an antipatharian from the Azores and Cape Verde Islands, with notes on its morphology, sexuality, host specificity, and biogeography. Mar Biodivers:1–22

  23. Kolbasov GA, Grygier MJ, Høeg JT, Klepal W (2008) External morphology of ascothoracid-larvae of the genus Dendrogaster (Crustacea, Thecostraca, Ascothoracida), with remarks on the ontogeny of the lattice organs. Zool Anz 247(3):159–183

    Article  Google Scholar 

  24. Kolbasov GA, Chan BKK, Petrunina AS (2015) Gorgonolaureus bicornutus sp. nov (Crustacea: Thecostraca: Ascothoracida) from off South-East Taiwan with notes on morphology and distribution. Zootaxa 3972(3):328–342

    Article  PubMed  Google Scholar 

  25. Lin HC, Kolbasov GA, Chan BKK (2016) Phylogenetic relationships of Darwin’s “Mr Arthrobalanus”: the burrowing barnacles (Cirripedia: Acrothoracica). Mol Phylogenet Evol 100(2016):292–302

    Article  PubMed  Google Scholar 

  26. Litvinova NM (1971) The brittle-stars of the genus Amphiophiura of the Pacific and Indian Oceans collected by Soviet Expeditions on the R/V “Vityaz” and “Akademician Kurchatov”. Tr Inst Okeanologii Akad N USSR 92:298–316

  27. Lütken CF, Mortensen T (1899) Reports on an exploration off the west coasts of Mexico, Central and Southern America and off the Galapagos Islands. XXV. The Ophiuridae. Memoirs of the Museum of Comparative Zoology 23(2):97–208

  28. Lyman T (1878) Ophiuridae and Astrophytidae of the “Challenger” expedition. Part I. Bulletin of the Museum of Comparative Zoology at Harvard College, Cambridge, Mass 5(7):65–168, 10 pl

  29. Lyman T (1879) Ophiuridae and Astrophytidae of the “Challenger” expedition. Part II. Bulletin of the Museum of Comparative Zoology at Harvard College, Cambridge, Mass 6(2):17–83, 10 pl

  30. McClendon JF (1909) The ophiurans of the San Diego region. Univ Calif Publ Zool 6(3):33–64

  31. Mortensen T (1936) Echinoidea and Ophiuroidea. Discovery Reports 12:199–348 pls. 1–9. (iii-1936)

    Article  Google Scholar 

  32. Moyse J (1983) Isidascus bassindalei gen. nov., sp. nov. (Ascothoracida: Crustacea) from Northeast Atlantic with a note on the origin of barnacles. J Mar Biol Assoc U K 63(1):161–180

    Article  Google Scholar 

  33. Newman WA (1974) Two new deep-sea Cirripedia (Ascothoracica and Acrothoracica) from the Atlantic. J Mar Biol Assoc U K 54(2):437–456

    Article  Google Scholar 

  34. Pyefinch KA (1939) Ascothoracica (Crustacea, Cirripedia). The John Murray Expedition, 1933–34 Scientific reports 5(9):247–262

  35. Sars GO (1872) Nye Echinodermer fra den norske kyst. K Vidensk Selsk Forh 1871:1–31

  36. Stephensen K (1935) Two crustaceans (a cirriped and a copepod) endoparasitic in ophiurids. Dan Ingolf Exped 3(12):1–18

  37. Utinomi H (1950) On another form of Acrothoracica, newly found from Formosa. Mem Coll Sci Kyoto Univ, Ser B 19:91–96

  38. Wagin VL (1947) (dated 1946). Ascothorax ophioctenis and the position of Ascothoracida Wagin in the system of the Entomostraca. Acta Zool (Stockholm) 27:155–267

  39. Wagin VL (1949) Ascothorax ophioctenis Djakonov and the position of the order Ascothoracida Vagin in the system of the Entomostraca. Uchenye Zapiski Leningradskogo gosudarstvennogo universiteta, 12, Ser. Biol Nauk 19:12–72 (in Russian)

    Google Scholar 

  40. Wagin VL (1954) On the structure, larval development, and metamorphosis of dendrogasterids (parasitic crustaceans of the order Ascothoracida). Uchenye Zapiski Leningradskogo gosudarstvennogo universiteta, Ser. Biol Nauk 35:42–89 (in Russian)

    Google Scholar 

  41. Wagin VL (1964) On Parascothorax synagogoides gen.n., sp.n. - parasite of Ophiura quadrispina Clark and on geographic distribution of Ascothoracida (Entomostraca). Tr Inst Okeanologii 69:271–284 (in Russian with English summary)

  42. Wagin VL (1968) Ascothorax gigas sp. nov. from the Antarctic ophiuroid Ophionotus victoriae and data on the distribution of the genus Ascothorax. Sb Kratkih Soobshch, Zool 2:10–19 (in Russian)

  43. Wagin VL (1976) Ascothoracida. Kazan. University Press, Kazan 141 pp. (in Russian)

    Google Scholar 

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The authors would like to thank Prof. Angelika Brandt and Prof. Marina Malyutina for inviting ASP to take part in the KURAMBIO II cruise and to Prof. Pedro Martinez Arbizu for providing assistance and help in his lab on board. We are grateful to Anastassya Maiorova for permission to use her photographs of the living animals. We are indebted to Prof. Mark J. Grygier for correction of our MS. We are obliged to Dr. Sabine Stöhr for consultations on hosts’ distribution. We would like to thank Dr. Lena Menzel for editorial revision.


For ASP and GAK, this study was financially supported by the Russian Foundation for Basic Research (grants 17-54-52006 MNT_a, 18-04-00624 А, and 15-29-02447 ofi_m). SEM and TEM studies, and drafting of the paper were supported by the Russian Scientific Foundation, grant 14-50-00029.

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Correspondence to Gregory A. Kolbasov.

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All applicable international, national, and/or institutional guidelines for the care and use of animals were followed by the authors.

Sampling and field studies

All necessary permits for sampling and observational field studies have been obtained by the authors from the competent authorities and are mentioned in the acknowledgements, if applicable.

Additional information

Cardiosaccus pedri sp. nov.

Figures 12, 13, 14, 15, 16, 17, 18, 19, 20, and 21


Ascothorax rybakovi sp. nov.

Figures 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11


Communicated by A. Brandt

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Kolbasov, G.A., Petrunina, A.S. The family Ascothoracidae Grygier, 1987, a review with descriptions of new abyssal taxa parasitizing ophiuroids and remarks on the invalidity of the genus Parascothorax Wagin, 1964 (Crustacea: Thecostraca: Ascothoracida). Mar Biodiv 49, 1417–1447 (2019).

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  • Cysticolous parasites of echinoderms
  • New species
  • Taxonomy
  • Morphology
  • Key to species
  • Distribution
  • SEM
  • Lattice organs