Snakeskin Chiton

Sypharochiton pelliserpentis

Description 6

A common oval chiton about 30mm long by 23mm wide (some sources say up to 50mm long).

Suter says the plate colour is "usually dull, dingy-olive or olive-green marked with black on the ridge and on the sides", but sometimes some plates are light grey, the others greenish or dark brown, rarely the ground-colour is orange. There are often black wedge-shaped markings along the crest of each plate.

The girdle has distinctive light and dark banding pattern of large oval scales, resembling the skin of a snake. The dark bands are the same hue as the body plates. The underside of the foot is pale orange.

They have parallel lines on each plate (running from front to back), and radial lines of small nodules fanning from the top centre back edge to the side edge of each plate and across the whole of the front and rear plates. But these features vary in visibility on each individual and may be worn away in older individuals, often encrusted with coralline algae or barnacles etc. The front plate is larger and much higher than the rear plate. The second plate is notably longer that the others.

The inside of the plates is blue, "indistinctly blotched with olivegreen". The front plate has 10 to 13 slits, the tail plate has 12 to 14 blunt slits and the rest have one slit on each edge.

Similar chitons: Sypharochiton torri (smaller, Stewart Island area), Chiton sinclairi (lines and nodules less pronounced, has dashes of colour along the plates).

Distribution 6

Found in the intertidal zone above mid-tide level. Often found with the shell much eroded clinging, like a limpet, to 'home' sites on rocks at low tide. North Island, South Island, Stewart Island, Chatham Islands.

Synonyms 6

Chiton pelliserpentis (Quoy and Gaimard, 1835)
Sypharochiton maugeanus (Iredale and May, 1916)
Sypharochiton pelliserpentis septentriones (Ashby, 1924)

References 6

New Zealand Mollusca, Marine Land and Freshwater Shells, A W B Powell, 1979
Manual of the New Zealand Mollusca. Henry Suter, 1913

Sources and Credits

  1. (c) Tony Wills, some rights reserved (CC BY-NC), uploaded by Tony Wills
  2. (c) Tony Wills, some rights reserved (CC BY-SA), uploaded by Tony Wills
  3. (c) Lisa Bennett, some rights reserved (CC BY), uploaded by Lisa Bennett
  4. (c) Jon Sullivan, some rights reserved (CC BY),
  5. Tony Wills, no known copyright restrictions (public domain), uploaded by Tony Wills
  6. (c) Tony Wills, some rights reserved (CC BY-SA)

More Info

iNaturalist NZ Map

Depth intertidal
Places Chatham Islands, North Island, South Island, Stewart Island