November 15, 2012
If, while watching this video, you thought of the classic arcade/cell phone/graphing calculator game Snake, you’re not the only one. This is a Illacme plenipes millipede, long thought extinct and rediscovered seven years ago. For an utterly unusual animal, one thing stands out: With up to 750 legs, it has more than any other creature found so far, including 9,999 other species of millipedes.
Yesterday, the first full description of the species was published in the joural ZooKeys. The study was led by Paul Marek of the University of Arizona. The millipede is known only from 17 live specimens Marek’s team found in a home range that is remarkably specific: three small wooded areas strewn with Arkose sandstone boulders in the foothills of San Benito County, California, near San Francisco.
The rareness of the millipede meant that from 1928 until 2005—when Marek, then a Ph.D. student, found a few specimens in the woods near San Juan Bautista—most scientists had simply assumed the species had gone extinct. Over the past seven years, Marek and his colleagues have taken several trips to the area, typically searching for hours before finding a single specimen clinging to the side of a boulder or tunneling four to six inches down into the ground.
In studying these specimens under a microscope, Marek has discovered a number of surprising characteristics that go beyond its legs. ”It basically looks like a thread,” Marek told LiveScience. “It has an uninteresting outward appearance, but when we looked at it with SEM [scanning electron microscopes] and compound microscopes, we found a huge, amazingly complex anatomy.”
The new analysis revealed that the millipede has no eyes, disproportionately long antennae and a rudimentary fused mouth adapted for sucking and piercing plant structures. It also has specialized body hairs on its back that produce silk, which may be used as a defense mechanism to clear bacteria off the millipedes’ bodies.
Of course, the legs are the most striking part of the species’ anatomy. Despite the name millipede, no species are known to have 1,000 legs, but Illacme plenipes comes closest (its Latin name actually means “in highest fulfillment of feet”). The male specimens examined had at most 562 legs, but the females had more, with the winner at 750.
Most millipedes have somewhere between 80 and 100 legs. Marek and his colleagues speculate that this species’ extreme legginess could be a beneficial adaptation for subterranean tunneling or even for clinging to the boulders widely found in the species’ habitat.
DNA analysis has revealed that its closest cousin, Nematozonium filum, lives in Africa, with the two species’ ancestors apparently splitting apart sometime soon after the breakup of Pangea, more than 200 million years ago.
The team has tried to grow the millipedes in a lab but has so far been unable to. They caution that the species could be extremely endangered—in 2007, they stopped searching for wild specimens out of fears that they were depleting the population—and advocate for a formal protection listing, so scientists will have the time to learn more about them before the millipedes go extinct.
November 5, 2012
In December 2010, visitors to Opape Beach, on New Zealand’s North Island, came across a pair of whales—a mother and her calf—that had washed ashore and died. The Department of Conservation was called in; they took photos, collected tissue samples and then buried the corpses at a site nearby. At first, it was assumed that the whales had been relatively common Gray’s beaked whales, widely distributed in the Southern Hemisphere. (You can see the graphic images here, should you wish.)
Months later, when researchers analyzed the tissue DNA, they were shocked. These were spade-toothed whales, members of the world’s rarest whale species, previously known only from a handful of damaged skulls and jawbones that had washed ashore over the years. Until this find, no one had ever seen a complete spade-toothed whale body. The researchers scrambled to exhume the corpses and brought them to the Museum of New Zealand Te Papa Tongarewa for further analysis.
“This is the first time this species—a whale over five meters in length—has ever been seen as a complete specimen, and we were lucky enough to find two of them,” said biologist Rochelle Constantine of the University of Auckland, one of the authors of a paper revealing the discovery that was published today in Current Biology. “Up until now, all we have known about the spade-toothed beaked whale was from three partial skulls collected from New Zealand and Chile over a 140-year period. It is remarkable that we know almost nothing about such a large mammal.”
The species belongs to the beaked whale family, which is relatively mysterious as a whole, mostly because these whales can dive to extreme depths and for very long periods—as deep as 1,899 meters and for as long as 30 minutes or more. Additionally, the majority of beaked whale populations are thinly distributed in very small numbers, so of the 21 species in the family, there are thorough descriptions of only three.
Of these species, the spade-toothed whale may have been the most mysterious. Scientifically known as Mesoplodon traversii, it was named after Henry H. Travers, a New Zealand naturalist who collected a partial jawbone that was found on Pitt Island in 1872. Since then, a damaged skull found on White Island in the 1950s and another found on Robinson Crusoe Island off the Coast of Chile in 1986 are the only evidence of the species.
Because the whales were never seen alive, scientists knew nothing of their behavior. In the paper, they are described as “the least known species of whale and one of the world’s rarest living mammals.”
“When these specimens came to our lab, we extracted the DNA as we usually do for samples like these, and we were very surprised to find that they were spade-toothed beaked whales,” Constantine said. To determine that, the researchers compared mitochondrial DNA from both of the stranded whales’ tissue samples and found that they matched that from the skulls and jawbones collected decades ago. “We ran the samples a few times to make sure before we told everyone,” Constantine said.
The researchers note that New Zealand’s national policy of collecting and sequencing DNA from all cetaceans washed ashore has proven especially valuable in cases like these—if this policy weren’t in place, no one might ever have known that the body of a spade-toothed whale had been seen for the first time.
This delayed discovery of a species that has been swimming the oceans all along hints at how much we still don’t know about the natural world—especially the oceans—even in this well-informed age. “It may be that they are simply an offshore species that lives and dies in the deep ocean waters and only rarely wash ashore,” Constantine said, explaining how it could take so long to find the species for the first time. “New Zealand is surrounded by massive oceans. There is a lot of marine life that remains unknown to us.”
September 19, 2012
In our October issue, Michelle Nijhuis joins wildlife biologists in searching Colorado’s caves and waterfalls for one of the world’s most mysterious bird species: the black swift. Although fewer than 100 breeding sites of the black swift are known, Nijhuis was lucky enough to see ornithologist Ron Torretta locate a black swift that had been geotagged in 2010, providing researchers with a cache of information about the wanderings of the enigmatic bird. Here are a few more of the most mysterious and elusive of the world’s bird species.
1. Night Parrot: Between 1912 and 1979, birders spotted this elusive species, native to the interior of Australia, exactly zero times—leading most scientists to believe it had gone extinct. Since then, a tiny handful of sightings of the nocturnal, yellow-green bird have occurred, and experts now estimate that the population is somewhere between 50 and 250 mature individuals. After the last verified sighting in November 2006, when park rangers in the state of Queensland turned up a decapitated specimen that had died after flying into a barbed-wire fence, the Australian government chose to keep the find temporarily secret while they searched for more night parrots, so as to avoid an influx of birders flooding the remote park in hopes of spotting one of the world’s rarest birds.
2. Ribbon-tailed Astrapia: Endemic to the forest highlands of Papua New Guinea, this bird has the longest tail feathers (in relation to body size) of any bird species, with feathers three times its body length. Unfortunately, this stunning plumage has enticed poachers; hunting, along with habitat loss, has led to the species being listed as “near threatened” by the International Union for Conservation of Nature. The species, the most recent bird of paradise to be documented, was first described by explorer Fred Shaw Mayer in 1938.
3. Palila: This species of Hawaiian honeycreeper has one particularly mysterious characteristic—it subsists almost exclusively on the seeds of the māmane plant, which contain a level of toxins that would kill any other small animal. Scientists aren’t sure how the birds digest the seemingly-lethal seeds, although the palila have been observed avoiding certain plants, indicating they might have a way of selecting seeds with lower levels of poison. In 1978, the federal government ruled that feral goats and sheep had to be removed from the palila’s only remaining habitat—the upper slopes of Mauna Kea on the Big Island of Hawai’i—since they consumed māmane plants and threatened the birds’ survival.
4. The Kakapo: Some 82 million years ago, the island of New Zealand broke off from what would become Australia, and the strange, flightless nocturnal parrot species called the kakapo began its unusual evolutionary path. In the absence of predators, it became the world’s largest type of parrot and lost the ability to fly; when European colonists introduced cats, rats and ferrets to New Zealand to control the population of rabbits, the kakapo was nearly wiped out. Now, just 126 wild kakapos live on three predator-free islands off the coast of New Zealand.
5. The Crested Ibis: Named for the crest of white plumage that extends from its nape, the crested ibis used to nest across Japan, China, Korea, Taiwan and Russia. By 1981, after years of habitat loss, just five individuals remained in the wild in Japan, and though scientists took the birds into captivity, a breeding program was unsuccessful. Now, the last remaining wild population—some 500 birds in the Chinese province of Shaanxi—is being buttressed by chicks hatched in captivity as part of a Chinese program. Although the species is still listed as endangered, scientists are cautiously optimistic that it is finally making a comeback.
May 1, 2012
We live in an age of alarming extinction, in which many species are lost in large part due to human activity. At the same time, the natural world is so complex that even after centuries of research, scientists are still rapidly discovering new species everywhere from mountain tops to rain forests to the ocean floor.
This paradox is aptly illustrated by an announcement made yesterday: 24 new species of lizards, known as skinks, have been discovered in the Caribbean islands. But half of them may be close to extinction, and some may already extinct in the wild.
The research was conducted by a team led by Blair Hedges, a biologist at Penn State University and one of the world’s foremost experts at identifying new forms of life. Previously, Hedges has been involved with the discovery of what were then the world’s smallest snake, lizard and frog. The two dozen species named in this paper, published in the journal Zootaxa, constitute one of the largest mass discoveries of lizards in centuries.
To identify the many species of skinks (formally, members of the family Scincidae), Hedges and his team examined specimens housed at zoos and conservation centers around the world. By comparing taxonomic features of the lizards (such as the shapes of scales) and using DNA analysis, they determined that there are a total of 39 distinct species of skinks that live in the Caribbean—6 species that were previously recognized, 9 that had been named long ago but had been considered invalid and the 24 entirely new ones.
“Now, one of the smallest groups of lizards in this region of the world has become one of the largest groups,” Hedges said in a press release. “We were completely surprised to find what amounts to a new fauna, with co-occurring species and different ecological types.” He has determined that the skinks came to the Americas roughly 18 million years ago, likely arriving from Africa on floating rafts of vegetation.
How did the skinks go unnoticed for so long? Hedges speculates that because large numbers of skinks had already disappeared by the start of the 20th century, scientists, tourists and local residents have been much less likely to encounter them in the years since. Additionally, many of the characteristics that distinguish the species from one another have been overlooked or weren’t detectable until now, especially those indicated by DNA analysis.
The researchers determined that the skinks have long been most threatened by an exotic intruder: the mongoose, introduced from India to Cuba in 1872 with the intention of reducing rat populations in sugarcane fields. Rat populations were partially controlled, but by 1900, nearly half of the islands to which the mongoose had spread were also without skinks, and the remaining lizards have dwindled in population ever since. Additionally, the researchers note, current human activities such as forest removal are likely contributing to the skinks’ endangered status. The research team hopes that their data will be used to plan future conservation efforts.
Theoretically, if you’re in the U.S. Virgin Islands, Trinidad and Tobago, or Martinique, you might try looking for a skink. But because each of the species is remarkably rare—with even the non-endangered ones qualifying as vulnerable—it’ll certainly be difficult. Above all, if you do want to find one, hurry up: there may not be much time left.
January 25, 2011
Clouded leopards—named for their large, cloud-like spots—are rare. They are medium-sized (a bit bigger than a housecat) tree dwellers with big teeth and big paws that let them hang upside down among the foliage. In 2006, scientists used DNA studies to determine that there were two species of clouded leopards: Neofelis nebulosa, which lives on the Asian mainland and is the subject of a breeding program at the National Zoo (producing some of the world’s most adorable kittens), and Neofelis diardi, the Sunda clouded leopard, found on the islands of Borneo and Sumatra.
Now a group of researchers led by the Leibniz Institute for Zoo and Wildlife Research in Germany has determined the the Borneo and Sumatra populations are really two separate subspecies, splitting this rare kitty into two even rarer varieties. The scientists, reporting in Molecular Phylogenetics and Evolution, analyzed DNA from 15 leopards on Borneo and 16 on Sumatra and also examined the skulls and coats of museum specimens. They found that the kitties on the two islands looked very similar on the outside but had significant differences in skull shape and in their genetics.
The scientists aren’t certain about the events that led to the evolution of the various species and sub-species, but here’s what they propose: The ancestor species to all modern clouded leopards was living in Southeast Asia when the super-volcano Toba erupted on Sumatra around 75,000 years ago, possibly plunging the Earth into a years-long volcanic winter. Two populations of clouded leopards survived—one in southern China, which evolved into the modern-day clouded leopard, N. nebulosa, and one on Borneo, which became the Sunda clouded leopard, N. diardi. When sea level was low, some of those Sunda clouded leopards were able to travel back to Sumatra, but when the last Ice Age ended, around 10,000 years ago, and sea levels rose, Borneo and Sumatra were once again isolated from each other and the two populations were left to evolve into sub-species apart from each other.