Lepidopleuridae

Belongs within: Neoloricata. The Lepidopleuridae are a group of small chitons in which the articulamentum is poorly developed (Smith 1960). Characters (from Smith 1960): Relatively small (less than 5 cm long); valves generally sculptured with granules closely set in lines or quincunx; valve coverage complete; girdle narrow, minutely spiculose or scaly; insertion plates lacking, or… Continue reading Lepidopleuridae

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Categorised as Sachitida

Ischnochitonina

Belongs within: Neoloricata.Contains: Callochiton, Acanthochitona, Notoplax, Mopaliidae, Chaetopleuridae, Callistochiton, Ischnochitonidae, Chitonidae. The Ischnochitonina are a group of chitons, including the greater number of living species, in which the ventral layer of the valves forms a well developed articulamentum (Smith 1960). The Cryptoconchidae, in which the dorsal tegmentum is reduced relative to the articulamentum, have been… Continue reading Ischnochitonina

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Categorised as Sachitida

Ischnochitonidae

Belongs within: Ischnochitonina.Contains: Stenoplax (Stenoradsia), Ischnochiton, Lepidozona. The Ischnochitonidae are a group of chitons in which the dorsum of the intermediate valves is divided into distinct lateral and central areas, often by a diagonal rib (Smith 1960). The Lepidochitonidae are a group of chitons in which the valve margins bear distinctly separated apophyses. With plate… Continue reading Ischnochitonidae

Mopaliidae

Belongs within: Ischnochitonina.Contains: Mopalia. The Mopaliidae are a group of chitons found in the Pacific Ocean and polar regions characterised by a more or less bristly girdle (Smith 1960). Characters (from Smith 1960): Small to large chitons with tegmentum divided into usual lateral and central areas, sculpture combining radial and longitudinal ribs or lirae that… Continue reading Mopaliidae

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Categorised as Sachitida

Chitonidae

Belongs within: Ischnochitonina.Contains: Chiton. The Chitonidae are a group of chitons characterised by the presence of well-developed pectination on the outside of the insertion plates (Smith 1960). Members of the subfamily Chitoninae have a microgranulose to strongly grooved tegmentum that lacks extrapigmentary ocelli (Beesley et al. 1998). Characters (from Smith 1960): Small to large chitons… Continue reading Chitonidae

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Categorised as Sachitida

Acanthochitona

Belongs within: Ischnochitonina. Acanthochitona is a cosmopolitan genus of chitons in which the dorsum of valves is ornamented with a sculpture of rounded nodules (Smith 1960). Characters (from Smith 1960): Small to medium-sized chitons, rather narrow and elongated, tegmentum sculpture consisting of separated nodules or pustules of round to tear-drop shape, generally arranged in radial… Continue reading Acanthochitona

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Categorised as Sachitida

Neoloricata

Belongs within: Aculifera.Contains: Leptochiton, Lepidopleuridae, Ischnochitonina. The Neoloricata are the clade of chitons, including all living species, in which the valves of the shell have a more or less hard inner, semiporcelanous layer (the articulamentum) that usually projects to overlap with adjoining valves (Smith 1960). Characters (from Smith 1960): Valve structure consisting of periostracum, tegmentum,… Continue reading Neoloricata

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Categorised as Sachitida

Aculifera

Belongs within: Sachitida.Contains: Chelodina, Neoloricata, Solenogastres, Caudofoveata. The Polyplacophora includes the chitons, molluscs in which the test is comprised of a series of separate overlapping valves surrounded by a spicular girdle. Living chitons had eight valves, but varying numbers are found in stem-group chitons. In the Ordovician to Cretaceous Chelodina, the test contained eight generally… Continue reading Aculifera

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Categorised as Sachitida