Physoclisti
Encyclopedia
Physoclisti are fishes that lack a connection between the gas bladder
and the alimentary canal.
Addition and removal of the gasses from the gas bladder in these fishes occurs through specialised structures called the gas gland and ovale respectively.
The pneumatic duct that connects the gut and gas bladder is present in the embryos of these fish but it is lost during development.This anatomical state is believed to be derived from the ancestral physostomous
state.
Some fishes like eels are anatomically physostomous, but their gas bladders function similar to those of physoclists.
Gas bladder
The swim bladder, gas bladder, fish maw or air bladder is an internal gas-filled organ that contributes to the ability of a fish to control its buoyancy, and thus to stay at the current water depth without having to waste energy in swimming...
and the alimentary canal.
Addition and removal of the gasses from the gas bladder in these fishes occurs through specialised structures called the gas gland and ovale respectively.
The pneumatic duct that connects the gut and gas bladder is present in the embryos of these fish but it is lost during development.This anatomical state is believed to be derived from the ancestral physostomous
Physostome
Physostomes are fishes that have a pneumatic duct connecting the gas bladder to the alimentary canal. This allows the gas bladder to be filled or emptied via the mouth. In contrast, fishes without any connection to their gas bladder are called Physoclisti. The physostome fish encompass the...
state.
Some fishes like eels are anatomically physostomous, but their gas bladders function similar to those of physoclists.