Frog discovered ‘gives birth’ – Newspaper Zócalo

tags: college, jim mcguire, herpetologist, Coahuila, science, california berkeley

Cd. of Mexico, MEXICO: herpetologist Jim McGuire, University of California Berkeley, has found the first direct evidence of a frog tadpoles gives birth instead of laying eggs. The new species was discovered decades ago on the island of Sulawesi (Indonesia). It had been speculated that gave direct light tadpoles, but never observed or mating frog or the ‘birth’

“Almost all frogs in the world. – Over 6,000 species – have external fertilization by which the male sperm ejected as the eggs are released by the female, “McGuire says. “But there are a lot of strange modifications to this standard pairing mode. This new frog is just one of 10-12 species that has evolved internal fertilization, of which he is the one who gives birth to tadpoles instead of frogs or putting fertilized eggs. “

McGuire and Ben Evans of McMaster University in Ontario, Canada, named the species Limnonectes larvaepartus and described in the journal PLoS ONE.

Frogs have developed an amazing variety of reproductive methods. Indeed, most male frogs fertilizes the eggs after the female lays them. But about a dozen species, including frogs tailed California, have developed ways to fertilize the eggs inside the body of the female.

However, internal fertilization mechanisms are poorly understood least two species of frogs tailed California, one of which has developed a kind of penis-shaped tail that facilitates the transfer of sperm . Tailed frogs lay their fertilized eggs under rocks in streams, but other frogs with internal fertilization give birth to frogs, miniature replicas of the adults.

Although internal fertilization is extremely rare among frogs, there are many other strange reproductive variations. Some frogs carry eggs in bags in the back, tadpoles in bags, or tadpoles transported in holes in the back. The two known species of gastric brooding frog, now extinct, were famous for swallowing their fertilized eggs, which were developed in his stomach, and gave light frogs mouth. Two genera in Africa are also involved in internal fertilization and giving birth to frogs without going through a tadpole stage free life.

In the puddles

The frogs with fangs so -called by two appendices as canines of the lower jaw that used in the struggle-may have evolved in a maximum of 25 species in Sulawesi, although L. larvaepartus is only the fourth to be described formally. With a weight ranging from 3.2 grams to 900 grams, L. larvaepartus is in the range 5-6 grams.

The new species seems to prefer giving birth to tadpoles in small pools or away currents, possibly to avoid the frogs with heavier tusks. There is some evidence that males can also protect tadpoles.

McGuire first encountered the frog just described in 1998, the year began studying the incredible diversity of reptiles and amphibians in Sulawesi, one island east of Borneo and the southern Philippines. The island is a geographical hodgepodge, having been formed from the merger of several islands about 8-10 million years ago.

“Sulawesi is an amazing place from the point of view of diversity of endemic species “he says, as most parts of the island are home to at least five species of fanged frogs living next to each other.

The fanged frogs are special, according to McGuire because they seem to represent an adaptive branching virtually unexplored with many species found in the same places, but adapted to occupy different ecological niches.