Sea piglet (Arrhis phyllonyx)

Distribution data supplied by the Ocean Biodiversity Information System (OBIS). To interrogate UK data visit the NBN Atlas.Map Help



Arrhis phyllonyx is a compact gammarid amphipod. It has a laterally compressed but moderately cylindrical body consisting of a head with two pairs of antennae, seven thoracic segments and limbs forming a pereon and six abdominal segments and limbs forming a pleon as well as a tail with three limbs. The head has a conspicuous downturned rostrum. The eyes are more or less joined dorsally. The telson is relatively small but entire. It is pale orange in colour. Little is known about the maximum size of Arrhis phyllonyx.

Recorded distribution in Britain and Ireland

A generally more northern species, it has been found off the south coast of Orkney, Scotland and off northern Ireland.

Global distribution



Arrhis phyllonyx is a pelagic species thought to inhabit deep offshore waters.

Depth range


Identifying features

  • Head with conspicuous downturned rostrum.
  • Eyes joined dorsally.
  • Pereopod 7 much longer than pereopod 6.
  • Ramus of third uropod scarcely longer than peduncle.
  • Telson small and entire.

Additional information

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  1. Englisch, U., Coleman, C.O. & W├Ągele, J.W., 2003. First observations on the phylogeny of the families Gammaridae, Crangonyctidae, Melitidae, Niphargidae, Megaluropidae and Oedicerotidae (Amphipoda, Crustacea), using small subunit rDNA gene sequences. Journal of Natural History, 37, 2461-2486

  2. Howson, C.M. & Picton, B.E., 1997. The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]

  3. Sainte-Marie, B. & Brunel, P., 1983. Differences in life history and success between suprabenthic shelf populations of Arrhis phyllonyx (Amphipoda Gammaridea) in two ecosystems of the Gulf of St. Lawrence. Journal of Crustacean Biology, 3, 45-67


  1. NBN (National Biodiversity Network) Atlas. Available from:

  2. OBIS (Ocean Biodiversity Information System),  2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. Accessed: 2024-05-18


This review can be cited as:

Barnes, M.K.S. 2008. Arrhis phyllonyx Sea piglet. In Tyler-Walters H. and Hiscock K. Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 18-05-2024]. Available from:

Last Updated: 22/05/2008