Question

Which of the following amphibians has the largest RBC?
(a) Amphiuma
(b) Ambystoma
(c) Siren
(d) Triton

Answer 1

Hint: In an amphibian, which is a long cylindrical body with four vestigial legs and feet comprising three toes, the largest Red Blood Corpuscle (RBC) is present. They are native to the south-central United States and are a genus of aquatic salamanders.

Complete answer:
Amongst vertebrates, amphibian RBC is the largest. The largest RBC of Amphibian and Proteus is approximately 70$\mu m$ in diameter.
The largest RBC is present in Amphiuma tridactylum. With an elongated, dark grey-black or brown colored body and tiny vestigial legs, it is a three-toed amphibian that looks very eel-like. Measuring $70\mu m \times 40\mu m$, they have the largest reported erythrocytes (RBC).

Amphiumas belong to nocturnal carnivores. They spend much of the time concealing permanent bodies of slow-flowing water, such as swamps, wetlands and lakes, in densely vegetated areas. Earthworms, fish, crustaceans, and other small invertebrates are the ones that amphiumas feed on.

Additional information: Those from amphibians, such as frogs, contain a DNA-bearing nucleus which is evident in the center of the cell, unlike traditional mammalian red blood cells. The amphibian circulatory system is fairly uncommon, with three chambers, two atria, and a single ventricle in their cores.
Most red blood cells of mammalians are highly developed and have lost their nucleus. The greatest difference between human blood cells and frog blood cells is that the red blood cells in the frog have a nucleus, while the human blood cells have no nucleus.
So, the correct answer is, ‘Amphiuma’.

Note: All vertebrates transport oxygen via hemoglobin packed in RBCs, except cold-water ice fish. The scale of Vertebrate RBCs varies by 30 fold. In amphibian red blood cells, the presence of a nucleus gives researchers easy access to large amounts of amphibian DNA. There is both a solid and a liquid component of frog blood. Solid components such as red and white blood cells are carried by the liquid plasma. Blood from frogs can be obtained and red blood cells are further separated by centrifugation. Purified cells can be treated with unique enzymes and detergents after removal of the residual plasma to digest the cellular envelope and release DNA from its protein complex. The DNA is then useful for experiments and scientific studies.