The Western Clawed Frog, also known as Xenopus tropicalis, is a type of frog found in the family Pipidae.
It’s special because it’s the only frog in its genus with a diploid genome. This means it has two sets of chromosomes, making it a great model organism for genetics research.
It’s related to the African Clawed Frog, Xenopus laevis, which is another important model organism for studying developmental biology.
What Are the Advantages of Using the Western Clawed Frog in Research?
There are several reasons why scientists like to use the Western Clawed Frog in their research.
Some of these reasons are:
- Shorter generation time: It takes less than 5 months for this frog to grow and reproduce, making it easier for scientists to study multiple generations quickly.
- Smaller size: The Western Clawed Frog is only 1.6 to 2.4 in (4 to 6 cm) in body length, making it easier to handle and study.
- More eggs per spawn: This frog can lay a large number of eggs at once, which is helpful for researchers who need a lot of samples.
Where Can the Western Clawed Frog Be Found?
The Western Clawed Frog is found in many countries across West Africa, including Benin, Burkina Faso, Cameroon, Ivory Coast, Equatorial Guinea, Gambia, Ghana, Guinea, Guinea-Bissau, Liberia, Nigeria, Senegal, Sierra Leone, Togo, and possibly Mali.
It lives in different types of habitats such as:
- Subtropical or tropical moist lowland forests,
- Moist savanna,
- Rivers and intermittent rivers,
- Swamps and freshwater lakes,
- Freshwater marshes,
- Rural gardens,
- Heavily degraded former forests,
- Water storage areas, ponds, and aquaculture ponds, and
- Canals and ditches.
What Does the Western Clawed Frog Look Like?
The Western Clawed Frog is a medium-sized frog with a somewhat flat body.
It has a snout-vent length of 1.1 to 2.2 in (28 to 55 mm), with females being larger than males. The frog’s eyes are big and sit high on its head.
There is a short tentacle just below each eye. The frog has short, plump limbs with fully webbed feet that have hard claws.
Its skin is finely textured, and its back can be pale or dark brown with small grey and black spots. The belly is dull white or yellowish with some dark patterns.
How Does the Western Clawed Frog Live in Its Environment?
This frog is an aquatic species and lives in the West African rainforest belt. It’s generally considered a forest-dwelling species.
In the dry season, the Western Clawed Frog lives in shallow streams and hides under tree roots, flat stones, or in holes in the riverbank.
It eats earthworms, insect larvae, and tadpoles. When the rainy season starts, it moves across the forest floor at night to find temporary pools.
Reproduction and Tadpole Development
Spawning can take place in large pools with lots of plants, or sometimes in muddy pools without any plants.
The frog lays single eggs that can either stick to plants or float. The tadpoles have wide mouths, no jaws, and long tentacles on their upper lips.
Their tails have wider ventral fins than dorsal fins. The tadpoles can be orange with transparent tails or have blackish tails in darker locations.
They eat by filtering tiny animals from the water. When they grow to about 2 in (5 cm) long, they turn into adult frogs through a process called metamorphosis.
How Is Gender Determined in The Western Clawed Frog?
Gender determination in most amphibians is controlled by sex chromosomes that look the same.
In the Western Clawed Frog, there are three sex chromosomes: Y, W, and Z.
These chromosomes create three male genotypes (YW, YZ, and ZZ) and two female genotypes (ZW and WW).
This means that the offspring of this frog can have different sex ratios, like 1:3 females to males or all females.
The genetic mechanism behind this gender determination system is still unknown.
It’s also unclear if having three sex chromosomes is a stable long-term strategy or if the species is going through a change in its sex chromosomes.
The Y chromosome seems to be the most recent development in the frog’s sex chromosomes, and it’s possible that the Z or Y chromosome could eventually disappear, leading to a simpler XY or ZW gender determination system.
You can check out what this amphibian looks like over here.