Vertebrate Zoology - V. M. Konstantinov 2011

Chordates
Gnathostomes
Class Osteichthyes - Subclass Actinopterygii - Superorder Chondrostei - Order Polypteriformes

Bichirs are a small, highly distinctive group of freshwater fish. Currently, a little over 10 species are known, distributed across tropical Africa. Their bodies are covered with large, rhombic scales that articulate flexibly with one another (Fig. 37). The dorsal fin consists of a series of small finlets, which inspired the common name of these fish. The pectoral fins feature a broad, fleshy base at their origin, giving bichirs an external resemblance to lobe-finned fish (see below). However, the skeletal structures of their fins are strikingly different.

Their swim bladder is exceptionally unique. It is paired, consisting of a larger right lobe and a smaller left lobe. Both lobes communicate with the gut via a common duct and function as an accessory breathing organ. Unlike lungfish and lobe-finned fish, however, bichirs lack internal nostrils. Paired spiracles are present. The digestive tract contains a spiral valve, and The Heart features an conus arteriosus.

Bichirs represent fish highly specialized for life in tropical Water bodies. Certain General characteristics they share with lungfish and lobe-finned fish arose through convergent evolution.

Class="center">Image

Fig. 37. Bichir



Last update: 13/08/2026

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