Glass frogs and walking fish

Wondering whether the two creature featured today are fictional ones? They certainly may seem so to you not only because of their names but also their unusual appearance. However, they are real life animals that are rather rare and strange looking.The Animal Kingdom is teeming with many such wonderful creatures , some of which are yet to be identified by scientists. As we have not seen most of these creatures alive or even in photographs, it is indeed hard to believe that such animals do exist even when we hear of them or see them in print.

The Glass frog as the name implies resembles an ornamental frog made of glass because of its see- through or transparent body.While the general background coloration of most glass frogs is primarily lime green, the abdominal skin of some members of this family is transparent. The internal organs including the heart, liver, and gastrointestinal tract are visible through this translucent skin, and that is why they have been given this name.

Imagine being able to see the animal’s inner organs right down to the beating heart? The translucent skin actually has an advantage for the glass frog because it makes him very difficult for predators to spot, as he almost becomes a part of the leaf he is sitting on. If you shine a light on a tree frog at night (if you can find one) all you will see is his eyes and a smudge for his skull. All frogs in the order Anura which belong to the amphibian family Centrolenidae are known as glass frogs. Based on a specimen collected in north eastern Ecuador, the "giant" Centrolene geckoideum, named by Marcos Jimenez de la Espad, in 1872 was the first species described. After that several other species were described but they were initially placed in the same genera as tree frogs.It was in 1951 that the glass frogs were placed in the Centolenidae family .

Glass frogs are said to have originated in South America and spread into Central America. Between the '50s and '70s, most species of glass frogs were known from Central America, particularly from Costa Rica and Panama.There are over 60 species of glass frogs living.

The unusual looking glass frogs are small, ranging from 3 to 7.5 centimetres (1.2 to 3.0 in) in length about the size o a fingernail. They are generally green in colour ,however, the skin along the lower surface of the body, is translucent. Similar in appearance to some green frogs and even tree frogs, these frogs have eyes that face forward not on the sides like most other frogs .

These frogs which are mostly arboreal can be found near rivers and streams during the breeding season. The female usually lays a clutch of tiny eggs not in the water but on leaves of trees or shrubs anywhere from 10 to 20ft up in the air.These leaves must be hanging over running water of either a stream, small river or creek so that once the eggs hatch, the tadpoles could fall easily into the water below.

The method of egg-laying on the leaf varies between species. Even though the eggs are less vulnerable to predators than those laid within water, they are likely to be affected by the parasitic maggots of some fly species. And because of this factor some glass frogs are reported to have shown parental care about their eggs. Once the tadpoles, which are born with a strong tail and fins, fall into the river down below the parents return to the canopy. However ,some glass frog species are known to eat their young.

There are 134 species of glass frogs with 60 of them threatened. Of the rest, 49 are classified as having "not enough data" to classify their status.In 2004 the International Union for Conservation of Nature and Natural Resources (IUCN) Red List declared hyalinobatrachium pellucidum as an endangered species. Fewer than 5,000 exist. The cause of threat is habitat loss due to small farmers and logging in the Amazonian slopes of the Ecuadorian Andes. IUCN recorded five specimens found in 1979 at Río Azuela in Ecuador. Even when assessors have revisited several times since then, they have found no other glass frogs.

Glass frogs are important because they are a bioindicator. As the climate changes, studying how the glass frogs cope will indicate how the other flora and fauna are handling the changes as well.

The diversity of the natural world is amazing. We need to learn as much as we can about it to conserve and protect the numerous species of fauna and flora that is disappearing over the years.

Like many animals the tiny and beautiful glass frogs too need to be protected. Another fascinating creature that must be conserved is the Mexican walking fish.The axolotl,(pronounced ax-oh-lot-ul), scientific name Ambystoma mexicanum is an aquatic salamander native to Mexico, which is colloquially known as the "Mexican walking fish". Although it is not a fish, but an amphibian, the Australians and New Zealanders frequently refer to the axolotl as the Mexican walking fish.

It is actually an amphibian in a paused state of metamorphism.In general all amphibious fish, some of which are able to spend long periods of time out of water and also use different types of locomotion;springing, snake-like lateral undulation, and tripod-like walking.

The axolotl is part of one of the three branches of class Amphibia, which also includes the frogs and toads (the Anurans), and the mainly eel-like order, Gymnophiona, which are also known as the Caecilians.If anyone of you is familiar with the cartoon series Pokemon you may think the Mexican walking fish inspired the creation of these cartoon characters. The features of these aquatic creatures, which average about 23 centimetres in length are indeed fascinating. Axolotl have external gills and a caudal fin that extends from behind the head to the vent. Branch like gills, which project outwards from the neck, on each side of the head. Each side is split into three branches, which are covered with feathery pink filaments.They do not have lids on their eyes .

They have wide heads.There are thin, long digits on their underdeveloped limbs .They have short legs with four digits in front and five on the hind feet.The bodies are dark coloured.They prefer a high altitude water body, that is surrounded by a terrestrial environment, like most neotenic species. It is found in regions having deep brackish water and plenty of vegetation. Axolotl is carnivorous and feeds on small creatures like insects, worms and even small fish. It smells the food first and then snaps at it and sucks it inside the stomach.

Axolotl is mainly found in the Mexican lakes of Chalco and Xochimilco, in Mexico city. Unfortunately, the Chalco lake was drained to avoid flooding and exists no longer. The Xochimilco has diminished too and exists just as canals. This is why the axolotl have decreased in number and are classed as an endangered species.

This little creature with half salamander and half fish like body is on the verge of extinction. Water pollution and habitat destruction are the two main reasons responsible for reduction in the number of Mexican walking fish. Scientists estimate that the number of axolotls, which used to be around 1,500 per square mile in certain areas, has reduced to just 25. This is the number of wild axolotls, however, there are large numbers of axolotls in captivity around the world.

The axolotl's unique ability to regenerate the lost body parts is simply amazing and has caught the attention of medical scientists.Do you know that they can even restore some parts of their brain? It has long been known that the axolotl is a worthy study due to its amazing healing and regeneration abilities.

Normal wound healing in animals occurs through the growth of scar tissue, which is not the same as the original tissue, nor is it as robust.

Normal wound healing also does not allow for most animals to re-grow a lost limb.Despite its endangered status, the use of the axolotl as a laboratory animal should ensure the species' survival, if only in captivity.

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FAST FACT

Glass frogs

* The glass frog is a freshwater creature that occupies tropical and subtropical forest territory and inland wetlands, including permanent rivers, streams, creeks and waterfalls.

* The family Centrolenidae now contains two subfamilies and twelve genera (Guayasamin et al., 2009).

* Centrolenidae is a diverse type of frogs distributed from southern Mexico to Panama, and through the Andes from Venezuela and the island of Tobago to Bolivia, with some species in the Amazon and Orinoco River basins, the Guiana Shield region, southeastern Brazil, and northern Argentina.

* The bones are visible from outside and in some species (including the Pichincha glass frog, the Pacific glass frog, the Cochran glass frog and lots of others) the bones are green while in other species they are white.

* A bioindicator is a species that provides clues about the health of the environment where it lives. As the Earth’s weather changes, some of the rain- and cloud forests where Glass Frogs live are becoming too dry, making life difficult for the frogs, as well as other plants and animals. By watching the glass frogs, scientists can learn what impact global warming has on these forests and the amazing species that inhabit them.

* Known as the hyalinobatrachium pellucidum (which means translucent skin), the glass frog is also referred to as the see-through frog,

* While some frogs eat their young, some males are highly territorial and show parental care.

Mexican walking fish

*Axolotl belongs to the family of 'mole salamanders'. *Amphibians are a completely separate group of animals even though some attempt to class them with lizards and reptiles .The fact that reptiles (and human beings too )have a four-chambered heart while amphibians have only three chambers is just one example of how appearance can be deceiving: salamanders might look like lizards, but they are very different indeed.

* Axolotls of various colours occur in captivity, including grey, shades of brown, leucistic (white with black eyes), golden albino, white albino, as well as other varieties, such as the melanoid (a near-black animal).

* The name "axolotl" comes from the Aztec language, "nahuatl". One of the most popular translations of the name connects the Axolotl to the god of deformations and death, Xolotl, while the most commonly accepted translation is "water-dog" (from "atl" for water, and "xolotl", which can also mean dog).

*The axolotl is fully capable of complete limb re-growth. The animal has the added scientific attraction of having especially large embryos, making it easier to deal with under laboratory conditions. Its embryo is also very robust, and can be spliced and combined with different parts of other axolotl embryos with a high degree of success.

* Neoteny is sometimes found in other amphibians, but tends to be caused by low levels of iodine (an essential element for animals to make thyroxine hormones, necessary for growth and development), or possibly by random genetic mutation. Research has also shown that very low temperatures can suppress the production of these hormones, thus also inducing neoteny.

* An adult Mexican walking fish ranges in length from 15- 45 centimetres

* Mexican walking fish becomes sexually mature at the age of about 12 months. The males can be identified by their longer tails .Females have a wider body and lay between 300 to 1000 eggs. Larvae hatch within two to three weeks.

Facts and pix: Internet