Hominid species may have co-existed

An ancient hominid known as Little Foot may have lived at roughly the same time as Lucy, another famous human forebear, a new study has found. The research, published in the journal Nature, suggests that early hominids may have been far more diverse than previously thought.

Discovered in a cave in South Africa in the early 1990s, Little Foot (named for his tiny feet) was first thought to be about 4 million years old. But later estimates, based on minerals found in the same cave, placed him closer to 2.2 million years old. For years, scientists could not agree. Now, an international team of researchers has turned to a dating technique that measures levels of aluminum and beryllium in the rock layer holding the fossil.

Their conclusion: Little Foot is 3.67 million years old, about half a million years older than Lucy. If accurate, the new estimate suggests that there may have been many different species of Australopithecus inhabiting a far greater range in Africa than previously thought.

“People like to think of evolution as a straight progression,” said Darryl E Granger, a geologist at Purdue University and lead author of the study. “But here we’ve got Lucy’s species in East Africa, and at the same time a very different Australopithecine a continent away. What it does is point to the complexity, the bushiness, of the family tree.”

Frog that can change skin texture
A  new species of frog discovered in Ecuador is the first vertebrate known to change its skin texture from smooth to spiny, researchers say.

The mutable species of rain frog possesses an ability previously observed only with invertebrates such as cuttlefish and octopuses. Around moss – plentiful in its native Ecuadorean forest – the frog sprouts tiny tubercles, presumably as camouflage. Away from the moss, the tubercles rapidly recede and the frog’s skin turns smooth.

Researchers discovered the tiny frog (about the size of a marble) in 2006, but it was three years before they observed its shifting abilities.

“We took a specimen back to the house in a cup to photograph it, and when we looked in the morning, we thought we had grabbed the wrong frog,” said Katherine Krynak, a biologist at Case Western Reserve University and an author of the study. “We put the frog back in the cup with some moss, and soon, it had the spines again.”
During their research, which was published in The Zoological Journal of the Linnean Society, the scientists discovered that a related species of frog could change its skin in a similar manner, raising questions of how the trait evolved. “Either these two different species from two different clades evolved the same trait, or all species had it and then lost the trait, or other species in this clade do this, too, and it’s just never been documented,” Katherine said.
Douglas Quenqua

A farmer ant’s unique fungal crop
Much like human farmers, fungus-farming ants meticulously maintain their subterranean gardens. They regularly fertilise, weed and tend to their crops. Now, researchers have discovered that one primitive species cultivates a kind of fungus that is entirely domesticated.

“These ants make their living by being farmers, and they are absolutely dependent on this fungus,” said Ted Schultz, an entomologist at the Smithsonian Institution. He and his
colleagues will describe their findings in a coming issue of The American Naturalist. Apterostigma megacephala was first described in 1999, based on four specimens found in Peru and Colombia. Ten years later, researchers discovered its nests in the eastern Amazon region of Brazil and realised that the ants cultivate a type of fungus that grows only in its nests and those of a species of leaf-cutter ants.

The fungus, Leucoagaricus gongylophorus, evolved only 2-8 million years ago. DNA sequencing shows that the ant belongs to an ancient lineage that dates back 39 million years. How and when the species got hold of the fungus remains a mystery, Ted said.

The leaf-cutter ant that cultivates the fungus evolved more recently, about 12 million years ago. Other primitive fungus-farming ants cannot
digest the fungus without dying, Ted said.
SINDYA N BHANOO
NYT