Why is ratfish called chimera?
Due to their teeth, chimaeras are commonly known as ratfish or rabbitfish. They also called spook fish or ghost shark because of their spectral appearance, but don’t be afraid, chimaeras are strange but have some charm. Chimaeras are oviparous, which mean that they lay eggs cases in the sand or buried in it.
Do chimeras have operculum?
Ratfishes are characterized by a large head and eyes and by a long, slender tail. They have an operculum , a hard, bony layer of tissue covering the gills, found in many bony fishes but absent in all other chondrichthyans.
How do chimaeras move?
Chimaeras move by flapping the large pectoral fins on the sides of their body, which makes them like they are flying through the water. Many species have a sharp, poisonous spine in front of the first dorsal fin on the top of their body.
Do rat fish have an operculum?
Ratfish do have a few features characteristic of the modern bony fishes, plus some interesting adaptations all their own. As in bony fishes, the upper jaw is fused with the skull (sharks can eject a detachable upper jaw to grab prey), and ratfish have a gill cover, or operculum, on either side of the head.
What is a chimera in the ocean?
In Greek mythology the ‘Chimaera’ was a monstrous fire-breathing hybrid creature. Chimaera are closely related to sharks, skates and rays. But they diverged from their shark relatives around 400 million years ago. They differ from sharks as they have: Upper jaws that are fused to their skull.
What is a long nose chimera?
The Rhinochimaeridae, commonly known as long-nosed chimaeras, are a family of cartilaginous fish. They are similar in form and habits to other chimaeras, but have an exceptionally long conical or paddle-shaped snout. The snout has numerous sensory nerve endings, and is used to find food such as small fish.
Which gills are covered by operculum?
In bony fish, the gills lie in a branchial chamber covered by a bony operculum (branchia is an Ancient Greek word for gills).
How is the operculum attached to the retina?
What is a retinal Operculum? The operculum, which can be seen as a whitish disc-shaped floater, remains attached to the posterior hyaloid membrane overlying the retinal hole. With time, the operculum contracts and deteriorates because of loss of retinal blood supply. In many cases, it is observed to be smaller than the underlying retinal defect.
How is a spotted ratfish different from a bony fish?
Like the bony fish—the large class that contains most fish—the spotted ratfish has a cover over its gills called an operculum. However, the ratfish gill cover is soft and fleshy while the bony fish gill cover is made of bone. Sharks lack an operculum. The ratfish has two dorsal fins on its back. There is a spine in front of the first one.
How are the opercular flaps of a ratfish important?
The opercular series is vital in obtaining oxygen. They open as the mouth closes, causing the pressure inside the fish to drop. Water then flows towards the lower pressure across the fish’s gill lamellae, allowing some oxygen to be absorbed from the water. In cartilaginous ratfishes, they present soft and flexible opercular flaps.
What kind of fish does not have an operculum?
Sharks, rays and relatives such as elasmobranch fishes lack the opercular series. They instead respire through a series of gill slits that perforate the body wall. Without the operculum bone, other methods of getting water to the gills are required, such as ram ventilation, as used by many sharks.