Tetrabranchia

former cephalopod taxon

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Last updated

July 14, 2026

Quick Summary

The term Tetrabranchia refers to a former subclass or order of Cephalopoda. This group is distinguished by having four gills, four heart auricles, and a large, chambered external shell. Existing forms within this classification are represented solely by the genus Nautilus. The Tetrabranchia also includes numerous extinct species, such as those found in the ammonoidea and nautiloidea groups. This contrasts with the dibranchia, which have only two gills.1

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cephalopod
Critical appraisal
…forms, which were considered as Tetrabranchia because Nautilus has four gills rather than two. This unnatural classification, accepted by the French zoologist Alcide d’Orbigny in 1838, was gradually modified through the efforts of the Swiss zoologist Adolph Naef and the German zoologist Georg Grimpe and later workers to the form…
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…forms, which were considered as Tetrabranchia because Nautilus has four gills rather than two. This unnatural classification, accepted by the French zoologist Alcide d’Orbigny in 1838, was gradually modified through the efforts of the Swiss zoologist Adolph Naef and the German zoologist Georg Grimpe and later workers to the form…
Read More