Family PYLOCHELIDAE Bate, 1888

Trizocheles spinosus [from Henderson 1888: pl. 11 fig. 1]

Museums

Regional Maps

• Pylochelidae Spence Bate, C. 1888. Report on the Crustacea Macrura collected by H.M.S. Challenger during the years 1873–76. Report on the Scientific Results of the Voyage of H.M.S. Challenger 1873–1876, Zoology 24: 1-942, i-xc figs 1-76 pls 1-150 [10].

  Type genus:

   Pylocheles A. Milne Edwards, 1880.
• Pomatochelidae Stebbing, T.R.R. 1914. South African Crustacea. Part VII. Annals of the South African Museum 15: 1-112 [2].

  Type genus:

   Pomatocheles Miers, 1879.

Taxonomic Decision for Synonymy

• Forest, J. 1987. Résultats de campagnes MUSORSTOM. Les Pylochelidae ou `pagures symetriques' (Crustacea Coenobitoidea). Mémoires du Muséum national d'Histoire naturelle, Paris [1936-1950] 137: 1-254 [25]

Introduction

Pylochelids differ from all other hermit crabs in having a calcified, segmented pleon, usually symmetrical. Removed from their portable shelter, pylochelids superficially resemble mud shrimp (Axiidea). Instead of gastropod shells, the typical hermit crab home, pylochelids inhabit cavities in small pieces of wood, stone, pumice or sponge, or use tusk shells or bamboo as homes. Members of this family are mostly distributed between 200 and 500 m depth, rarely reaching as shallow as 20 m or exceeding 1500 m. In deep water, the body in one genus of deep-water pagurids, Porcellanopagurus, is also straight and symmetrical, but bivalve shells are used for protection.

Pylochelids form an unusual family of more or less symmetrical-bodied `hermit crabs' that live in a variety of objects other than coiled gastropod shells. Their homes include tusk shells (Scaphopoda: Dentalidae), sponges, dead corals, calcareous rocks, pieces of bamboo or other hollow plant material, and even mangroves. Their chelae are often specialised to form an operculum, completely closing the cavity in which they live. They are found in all oceans, from shallow intertidal to relatively deep water. The family was revised thoroughly by Forest (1987), who recognised six subfamilies, only two of which are represented in Australia.

Diagnosis

Body hermit crab-like, pleon symmetrical (asymmetrical only in Mixtopagurus), pleonites separate, calcified and distinct. Chelipeds subequal. Maxillipeds 3 adjacent at base. With paired pleopods on pleonites 2–5.

Diagnosis References

Poore, G.C.B.,& Ahyong, S.T. 2023. Marine decapod Crustacea. A guide to families and genera of the World. Melbourne : CSIRO Publishing pp. 928.

General References

Forest, J. 1987. Résultats de campagnes MUSORSTOM. Les Pylochelidae ou `pagures symetriques' (Crustacea Coenobitoidea). Mémoires du Muséum national d'Histoire naturelle, Paris [1936-1950] 137: 1-254

History of changes