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Family  Cryptoplacidae

Cryptoplacid chitons




This is a small family of very elongate, worm-like chitons. There is only one genus, Cryptoplax, which occurs throughout the Indo-West Pacific region. Species have valves reduced in size, not in contact in adults, embedded in a wide, densely spiculose girdle.

Family Reference:

  • Iredale, T. & Basset Hull, A.F. 1927 Family Cryptoconchidae Pp. 64-90 in A Monograph of the Australian Loricates. Royal Zoological Society of New South Wales, Sydney. 168 pp. (This is a consolidated and repaginated version of the same material that was published in sections in The Australian Zoologist over the years 1923-1927).

  • Gowlett-Holmes, K. 1998. Family Cryptoplacidae. P. 189 in Beesley, P.L., Ross, G.J.B. & Wells, A. (eds) Mollusca: The Southern Synthesis. Fauna of Australia. Vol. 5. CSIRO Publishing: Melbourne. Part B. viii 565-1234 pp.

  • Gowlett-Holmes, K. 2001. Cryptoplacidae. Pp 45-48 in Wells, A. & Houston, W.W.K. (eds) Zoological catalogue of Australia. Vol. 17.2 Mollusca: Aplacophora, Polyplacophora, Scaphopoda, Cephalopoda. Melbourne: CSIRO Publishing, Australia.

  • Kaas, P. & Van Belle, R. This family was not treated by Kaas and van Belle.


The only species of Cryptoplax known from NSW is detailed here.

Cryptoplax iredalei Ashby, 1923 was recorded as a NSW species in the NSW checklist (Iredale & McMichael, 1962) , but it is not included as a NSW species in the subsequent list of Gowlett-Holmes (2001, p. 41). There are no specimens from NSW in the Australian Museum collection. Therefore, it is accordingly removed from the NSW list.

Identification Notes:

Members of this family are easily identified by the elongate body, small valves and spiculose girdle.

See the introduction to Acanthochitonidae for an explanation of shell characters.


Copyright Des Beechey 2019