Living on the edge – first survey of loriciferans along the Atacama Trench

Keywords: deep-sea, HADES-ERC, Loricifera, meiofauna, Pliciloricus ukupachaensis sp. nov., Rugiloricus


The fauna of Loricifera along a north-south longitudinal transect following the Atacama Trench was explored. Whereas no loriciferans were collected from the actual trench, the continental slope and surrounding abyssal plains yielded two species of Rugiloricus and two of Pliciloricus. All four species are considered as new to science, but only one of them could be formally described. The new species, Pliciloricus ukupachaensis sp. nov., is closely related with the North Atlantic Pliciloricus leocaudatus, and the two species share different morphological traits, including an enlarged anal field with conspicuous pentagonal and hexagonal fields formed by strong, cuticular ridges. Among other peculiar traits, the new species is characterised by having strongly reduced trichoscalid plates and no double trichoscalids. Comparison with previously published, unidentified specimens suggests that the new species’ distributional range might reach as far as Oregon off the US west coast.


Fujimoto S. & Kristensen R.M. 2020. Loricifera. In: Schmidt-Rhaesa A. (ed.) Guide to the Identification of Marine Meiofauna: 415–427. Verlag Dr Friedrich Pfeil, Munich.

Fujimoto S. & Murakami C. 2020. A new genus and species of Nanaloricidae (Loricifera: Nanaloricida) from the Clarion-Clipperton Fracture Zone. Zoologischer Anzeiger 289: 177–188.

Fujimoto S., Yamasaki H., Kimura T., Ohtsuka S. & Kristensen R.M. 2020. A new genus and species of Loricifera (Nanaloricida: Pliciloricidae) from the deep waters of Japan. Marine Biodiversity 50: e103.

Gad G. 2005. Giant Higgins-larvae with paedogenetic reproduction from the deep sea of the Angola Basin – evidence for a new life cycle and for abyssal gigantism in Loricifera? Organisms Diversity and Evolution 5: 59–75.

Gad G. 2009. Culexiregiloricus, a new genus of Nanaloricidae (Loricifera) from the deep sea of the Guinea Basin (Southeast Atlantic). Zootaxa 2096 (1): 33–49.

Gad G. & Martínez Arbizu P. 2005. First report of Arctic Loricifera – a new Rugiloricus-species from the Laptev Sea. Marine Biology Research 1: 313–325.

Grzelak K., Zeppilli D., Shimabukuro M. & Sørensen M.V. 2021. Hadal mud dragons: first insight into the diversity of Kinorhyncha from the Atacama Trench. Frontiers in Marine Science 8: e670735.

Heiner I. 2004. Armorloricus kristenseni (Nanaloricidae, Loricifera), a new species from the Faroe Bank (North Atlantic). Helgoland Marine Research 58: 192–205.

Heiner I. & Kristensen R.M. 2005. Two new species of the genus Pliciloricus (Loricifera, Nanaloricida, Pliciloricidae) from the Faroe Bank, North Atlantic. Zoologischer Anzeiger 243 (3): 121–138.

Heiner I. & Neuhaus B. 2007. Loricifera from the deep sea at the Galápagos Spreading Center, with a description of Spinoloricus turbatio gen. et sp. nov. (Nanaloricidae). Helgoland Marine Research 61: 167–182.

Heiner I. & Neuhaus B. 2010. Phylum Loricifera: corset worms. In: Gordon D.P. (ed.) New Zealand Inventory of Biodiversity, Volume 2: Kingdom Animalia: Chaetognatha, Ecdysozoa, Ichnofossils: 472– 475. Canterbury University Press, Christchurch, New Zealand.

Heiner I., Boesgaard T.M. & Kristensen R.M. 2009. First time discovery of Loricifera from Australian waters and marine caves. Marine Biology Research 5: 529–546.

Higgins R.P. & Kristensen R.M. 1986. New Loricifera from Southeastern United States coastal waters. Smithsonian Contributions to Zoology 438: 1–70.

Kristensen R.M. 1983. Loricifera, a new phylum with Aschelminthes characters from the meiobenthos. Zeitschrift für zoologische Systematik und Evolutionsforschung 21: 163–180.

Kristensen R.M. & Gad G. 2004. Armorloricus, a new genus of Loricifera (Nanaloricidae) from Trezen ar Skoden (Roscoff, France). Cahiers de Biologie marine 45: 121–156.

Kristensen R.M. & Shirayama Y. 1988. Pliciloricus hadalis (Pliciloricidae) a new loriciferan species collected from the Izu-Ogasawara Trench, Western Pacific. Zoological Science 5: 875–881.

Kristensen R.M., Gooday A.J. & Goineau A. 2019. Loricifera inhabiting spherical agglutinated structures in the abyssal eastern equatorial Pacific nodule fields. Marine Biodiversity 49: 2455–2466.

Neves R.C. & Kristensen R.M. 2016. Spinoloricus neuhausi (Loricifera, Nanaloricidae), a new deep sea species from Galápagos Spreading Center. Zoologischer Anzeiger 265: 171–177.

Neves R.C., Reichert H., Sørensen M.V. & Kristensen R.M. 2016. Systematics of Phylum Loricifera: identification keys of families, genera and species. Zoologischer Anzeiger 265: 141–170.

Neves R.C., Kristensen R.M., Rohal M., Thistle D. & Sørensen M.V. 2019. First report of Loricifera from the North East Pacific Region, with the description of two new species. Marine Biodiversity 49: 1151–1168.

Neves R.C., Kristensen R.M. & Møbjerg N. 2021. New records on the rich loriciferan fauna of Trezen ar Skoden (Roscoff, France): description of two new species of Nanaloricus and the new genus Scutiloricus. PLoS ONE 16: e0250403.

Pardos F. & Kristensen R.M. 2013. First record of Loricifera from the Iberian Peninsula, with the description of Rugiloricus manuelae sp. nov. (Loricifera, Pliciloricidae). Helgoland Marine Research 67: 623–638.

Shimabukuro M., Zeppilli D., Leduc D., Wenzhöfer F., Berg P., Rowden A.A. & Glud R.N. 2022. Intra and inter spatial variability of meiofauna in hadal trenches is linked to microbial activity and food availability. Scientific Reports 12: e4338.

Sørensen M.V., Rohal M. & Thistle D. 2018. Deep-sea Echinoderidae (Kinorhyncha: Cyclorhagida) from the Northwest Pacific. European Journal of Taxonomy 456: 1–75.

Sørensen M.V., Grzelak K., Kristensen R.M. & Herranz M. 2022. First account on Loricifera from New Zealand: a new species of Pliciloricus, and a Shira larva with postlarva representing the new genus and species Patuloricus tangaroa gen. et sp. nov. Zoologischer Anzeiger 299: 207–220.

Vincx M. 1996. Meiofauna in marine and fresh water sediments. In: Hall G.S. (ed.) Methods for the Examination of Organismal Diversity in Soils and Sediments: 214–248. CABI University Press, Cambridge, MA.

How to Cite
Sørensen, M. V., Herranz, M., Grzelak, K., Shimabukuro, M., Kristensen, R. M., & Zeppilli, D. (2023). Living on the edge – first survey of loriciferans along the Atacama Trench. European Journal of Taxonomy, 879(1), 162-187.
Research article