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Opercular series in bony fish: operculum (yellow), preoperculum (red), interoperculum (green) and suboperculum (pink) The operculum is a series of bones found in bony fish and chimaeras that serves as a facial support structure and a protective covering for the gills ; it is also used for respiration and feeding.
Chimaeras differ from other cartilagenous fish, having lost both the spiracle and the fifth gill slit. The remaining slits are covered by an operculum, developed from the septum of the gill arch in front of the first gill. [6] The shared trait of breathing via gills in bony fish and cartilaginous fish is a famous example of symplesiomorphy.
After the appearance of jawed fish (placoderms, acanthodians, sharks, etc.) about 420 million years ago, most ostracoderm species underwent a decline, and the last ostracoderms became extinct at the end of the Devonian period. More recent research indicates that fish with jaws had far less to do with the extinction of the ostracoderms than ...
An operculum (fish), a flap that covers the gills in bony fishes and chimaeras. The cover that rapidly opens a cnida of a cnidarian such as a jellyfish or a sea anemone. The lid may be a single hinged flap or three hinged flaps arranged like slices of pie. [1] [3] In insects, the operculum is the name for one or more lids covering the tympanal ...
In practice, fish anatomy and fish physiology complement each other, the former dealing with the structure of a fish, its organs or component parts and how they are put together, such as might be observed on the dissecting table or under the microscope, and the latter dealing with how those components function together in living fish. The ...
The internal shell is nacreous. They have a brown, entirely corneous, circular, multispiral operculum which fits the aperture snugly. The operculum is formed of numerous gradually increasing whorls with a central nucleus. The aperture may be entire, tetragonal or rounded and has no reflected lip. The peristome is generally not continuous.
Shell of marine snail Lunella torquata with the calcareous operculum in place Gastropod shell of the freshwater snail Viviparus contectus with corneous operculum in place. The operculum (Latin for 'cover, covering'; pl. opercula or operculums) is a corneous or calcareous anatomical structure like a trapdoor that exists in many (but not all) groups of sea snails and freshwater snails, and also ...
The Operculum (fish) is scaly and its upper margin has a small, flat spine enclosed within the skin. [8] The smallest species is S. xenochrous with a maximum published total length of 22 cm (8.7 in) while the largest is S. monogramma with a maximum published total length of 38 cm (15 in). [6]