Question

Lepidosiren is
A. Mackerel
B. Sardine
C. American lungfish
D. Pilotfish

Answer 1

Hint: It belongs to kingdom Animalia and phylum Chordata. It is a specific genus belonging to class Pisces. They have bony endoskeleton and are eel-shaped.

Complete Answer:
- In this specific question, we need to understand that under kingdom Animalia, Phylum Chordata, we have Class Pisces which contains jawed vertebrates along with definite organs for every metabolic process. The organisms inside this group are poikilotherms, having no ability to maintain their body temperature.
- All the fishes come within this group. They are usually present in freshwater, marine water, and brackish water. Their body is mostly elongated and streamlined. Their body is differentiated into a head, trunk, and tail. They carry gills for respiration and swim using their tail.

Pisces are mainly divided into two groups: Chondrichthyes and Osteichthyes.
- Let us know precisely about these groups. Students remember that the Chondrichthyes are present majorly in the marine environment, comprising all cartilaginous fishes without air bladders. Eg: Scoliodon.
- The other group Osteichthyes is found in both marine and freshwater, consisting of all bony fishes with air bladders. Claspers are absent. The gills are protected with an operculum. Lepidosiren, an American Lungfish is an example. They are eel-shaped with minute heads and dig pits inside the ground forming “L” shaped nests by biting the soil and ejecting mud by way of gill openings for their offspring. They are found in lentic water bodies full of vegetation and marshy conditions.
- It is well researched that lungfishes are more closely phylogenetically linked to land vertebrates than to ray-finned bony fishes i.e. Actinopterygii. Lungfishes, being carnivorous, prey on insects, mollusks, fishes, etc. through stalking, then capturing them by swiftly opening mouths to put negative pressure that draws them in.

Hence, the correct option is C.

Note: The fact that other than Chondrichthyes and Osteichthyes, Pisces is also classified into one another group called Placodermi, a group that existed till the Devonian period only. Remember, this Lepidosiren is an eel-shaped, slow-moving lungfish that lives in swamps.