Rat Fish / Ghost Sharks / Spook fish / Rabbit fish ( নিগনি মাছ )

Scientific name: Chimaera sp.

Classification

Phylum: Chordata - Dorsal tubular nerve cord, notochord and gill slits present.

Subphylum: Vertebrata - Vertebral column present.

Superclass: Gnathostoma -Jaws and paired appendages present

Class: Elasmobranchii- Endoskeleton cartilaginous. Scales are usually placoid. The notochord is rudimentary. Spiral valve in the intestine. Opercula absent

Subclass: Bradyodonti-Dentition of crushing type.

Order: Holocephali- Spiracle absent. Operculum present. Skull autostylic with two dorsal fins and an anal fin.

Genus: Chimaera

Habit and Habitats: Chimaeras are cool-water, marine fishes that live at shallow to moderate depths between 80 and 2600 m, where they usually swim just above the bottom.

Characteristics

1. The body is shark-like with a compressed head and blunt snout. The mouth is bounded by lip-like folds. Mouth and nostril ventral in position.
2. Gill-slits communicate with the exterior by a single branchial opening below the operculum which is not bony and covers the gills. Spiracles absent.
3. There are two large dorsal fins and a small ventral fin. The first dorsal fin bears an immensely bony anterior erectile dermal spine while the second dorsal fin is non-erectile. The paired pectoral and pelvic fins are enlarged. The ventral fin is small.
4. The caudal fin is like a folded tail, is produced into whip-like filament and is of diphycercal type.

                                                              

Videos

Ghost Shark Caught on Camera for the First Time. Source: YouTube, National Geographic

        Chimaera: The Deep Sea Phantom. Source: YouTube, Animalogic

References

• Practical zoology vertebrates by S.S Lal
• Wikipedia
• ScienceDirect
• The life of invertebrates by J.Z Young