Ischnochitonidae Family of Ischnochitons

One Chiton of the Ischnochitonidae Family can be found in this website:

Conspicuous Chiton, Stenoplax conspicua. A representative of the Ischnochitonidae Family of Ischnochitons.

Shells in the Family Ischnochitonidae are Polyplacophora mollusks. The word polyplacophora means “bearing many plates”. Shells in this Class are made up of eight separate, overlapping, plates, called valves. The underside and ends of the valves are attached to a tough mantle which covers the rest of the animal.  This armor plating provides excellent protection,  while being flexible enough to allow the animal to mold and attach itself to irregular hard surfaces. They can also roll into a ball if dislodged from their attachment spot. Family Ischnochitonidae is in the Order Chitonida, meaning that their valves have slit insertion plates. There are three subfamilies in Chitonidae: Acanthopleurinae with five genera and twenty species, Chitoninae with six genera and one hundred thirty-six species, and Toniciinae with three genera and sixty-one species. Shells in this Family are commonly called Ischnochitons or Ischnochitonids.

Ischnochitons have an oval outline,  a flattened profile, and bilateral symmetry. Their eight plates make them easy to distinguish as Polyplacophora mollusks, but differentiating between the several Orders and Families is difficult to do in the field, as it requires removing the plates from the mantle to examine their structure, and microscopic examination of the radula.  The plates may be smooth or sculpted with lengthwise or radial ribs, beads, granules, pustules, or knobs. The broader end valve is the head valve and the narrower end valve is the tail valve. Ischnochitons are more varied in color than True Chitons. They may be black,  blue, brown, gray, green, red, or pink in color. They may mottled, banded, blotched, or spotted.  Ischnochitons tend to have fine to coarse scales on their girdles. They can exceed 10 cm (3.9 inches) in length.

Ischnochitons are found attached to rocks, stones, shells, and other hard substrates. Sometimes they are partially buried in sand. They live in the intertidal zones and to depths exceeding 4390 m (14,399 feet). Most species are found shallower than 20 m (66 feet).  Ischnochitons vary in their diet and may be herbivores, omnivores, or carnivores. Ischnochitons are gonochoric and reproduce sexually, usually through broadcast spawning, but some species spermcast, with the fertilized eggs then brooded between the mantle and the shell (pallial groove).

Ischnochitons are found worldwide in polar, temperate, and tropical waters.