An 'Extinct' Frog Makes a Comeback in Israel

June 4, 2013 — The first amphibian to have been officially declared extinct by the International Union for Conservation of Nature (IUCN) has been rediscovered in the north of Israel after some 60 years and turns out to be a unique "living fossil," without close relatives among other living frogs.

Credit: Sarig Gafny

The Hula painted frog was catalogued within the Discoglossus group when it was first discovered in the Hula Valley of Israel in the early 1940s. The frog was thought to have disappeared following the drying up of the Hula Lake at the end of the 1950s, and was declared extinct by the IUCN in 1996. As a result, the opportunity to discover more about this species' history, biology and ecology was thought to have disappeared.

However, a team of Israeli, German and French researchers now report in the scientific journal Nature Communications on an in-depth scientific analysis of this enigmatic amphibian.

Based on new genetic analyses of rediscovered individuals and the morphologic analyses of extant and fossil bones, the conclusion is that the Hula frog differs strongly from its other living relatives, the painted frogs from northern and western Africa. Instead, the Hula frog is related to a genus of fossil frogs, Latonia, which were found over much of Europe dating back to prehistoric periods and has been considered extinct for about a million years,

Continued

Fish DNA Makes Limbs Sprout in Mice

Tia Ghose, LiveScience Staff Writer

Date: 17 April 2013 Time: 01:01 PM ET

The genome of a primitive fish that was once thought to have died when the dinosaurs did has now been sequenced by scientists — and when put into mice, some of the fish DNA caused mice to sprout limbs.

The new analysis, described today (April 17) in the journal Nature, could help to reveal how primitive fish swapped their fins for limbs when they moved from land to sea.

The fish, called a coelacanth, seems to carry snippets of DNA that can turn on genes that code for forelimbs and hind limbs in mice. The new discovery could shed light on how four-legged creatures, called tetrapods, evolved.

"It really is a cornerstone from which we can view tetrapod evolution," said study co-author Chris Amemiya, a geneticist at the Benaroya Research Institute in Seattle, Wash.

Living fossil

The coelacanth was once thought to have gone extinct about 70 million years ago, roughly around the time dinosaurs vanished. But in 1938, a fish trawler brought a bluish-purple, 3.3-foot-long (1 meter) fish with fleshy fins to the South African naturalist Marjorie Courtenay-Latimer. It turned out to be an African coelacanth.

Continued:  http://www.livescience.com/28797-coelacanth-genome-sequenced.html

Skull Confirms Older Origin for 'Living Fossil' Fish

A group of ancient fish, called coelacanths, have changed so little over time they are known as "living fossils." Now, the remains of a skull found in the Yunnan Province of China, confirms these creatures have been around, largely unchanged, for more than 400 million years.

Once thought to have died out at roughly the time the dinosaurs disappeared, the first living coelacanth was discovered in a fishing net in 1938 off the eastern coast of South Africa. Since then, others have turned up elsewhere along the coasts of the Indian Ocean. 

While it's clear their history goes way back, the fossils they left behind have been scarce so far. A lower jawbone, more than 400 million years old and discovered in Australia, hinted at the earliest known emergence of coelacanths whose appearance matched the two species alive today. This small fossil has been described as the oldest coelacanth, but the authors of the recent research write that it offers so little information that it cannot be reliably placed within the fishes' family tree.

The newest fossil evidence, the remains of a skull, date back to almost the same time and contain more definitive features that indicate both it and the Australian fossil were "modern" coelacanths, according to the study researchers writing in the April 10 issue of the journal Nature Communications.

Read on:  http://www.livescience.com/19602-living-fossil-fish-coelacanth.html

2nd coelacanth population found off Tanzania coast (via Chad Arment)

The Yomiuri Shimbun
(Nov. 10, 2011)

A team of Japanese researchers has discovered a hitherto unknown population of coelacanths, a fish species known as a "living fossil," off southeast Africa.

The researchers from Tokyo Institute of Technology and other entities said the newly found breeding group of coelacanths linked to the site has existed for more than 200,000 years without genetic contact with other groups.

Researchers had believed there was only one breeding group of the species off Africa.

The team published the results in an online edition of the Proceedings of the National Academy of Sciences of the United States.

Coelacanths have been found only in the sea off Africa and Indonesia. In Africa, an area in the sea around the Comoros Islands near Madagascar is home to the only previously known population of the fish.

Tokyo Institute of Technology Prof. Norihiro Okada and his colleagues analyzed genes of more than 20 coelacanths caught off Tanga, northern Tanzania, and nearby sites. The areas are nearly 1,000 kilometers north-northwest of the Comoros Islands.

The results showed the fish belong to a population genetically distinct from that off Comoros Islands.

The two groups seem to have separated 200,000 to 2 million years ago, the researchers said.

Considering the number of fish caught, the researchers assume the newly discovered population may comprise hundreds of coelacanths near the site.

http://www.yomiuri.co.jp/dy/features/science/T111108004421.htm

Loving the Chambered Nautilus to Death

It is a living fossil whose ancestors go back a half billion years — to the early days of complex life on the planet, when the land was barren and the seas were warm.       

Naturalists have long marveled at its shell. The logarithmic spiral echoes the curved arms of hurricanes and distant galaxies. In Florence, the Medicis turned the pearly shells into ornate cups and pitchers adorned with gold and rubies.

Now, scientists say, humans are loving the chambered nautilus to death, throwing its very existence into danger.

“A horrendous slaughter is going on out here,” said Peter D. Ward, a biologist from the University of Washington, during a recent census of the marine creature in the Philippines. “They’re nearly wiped out.”

The culprit? Growing sales of jewelry and ornaments derived from the lustrous shell. To satisfy the worldwide demand, fishermen have been killing the nautilus by the millions, scientists fear. Now marine biologists have begun to assess the status of its populations and to consider whether it should be listed as an endangered species to curb the shell trade.

On eBay and elsewhere, small nautilus shells sell as earrings for $19.95, and as pendants for $24.95. Big ones — up to the size of plates — can be found for $56, often bisected to display the elegant chambers.

As jewelry, the opalescent material from the shell’s inner surface — marketed as a cheaper alternative to real pearl — can fetch $80 for earrings, $225 for bracelets and $489 for necklaces.

Catching the nautilus is a largely unregulated free-for-all in which fishermen from poor South Pacific countries gladly accept $1 per shell.

Scientists worry that rising demand may end up eradicating an animal that grows slowly and needs 15 years or more to reach sexual maturity — an unusually long time for a cephalopod. (Its cousins include the squid and the octopus.)

“In certain areas, it’s threatened with extermination,” said Neil H. Landman, a biologist and paleontologist at the American Museum of Natural History and the co-editor of “Nautilus: The Biology and Paleobiology of a Living Fossil,” a compendium of scientific reports.

The nautilus lives on the slopes of deep coral reefs in the warm southwestern Pacific. While it is easy to catch with baited traps on long lines, the depths — as much as 2,000 feet, below the range of sunlight and scuba divers — make it hard to study.

So to find out just how endangered the nautilus is, biologists began a formal census last summer in at least six regions known to harbor the shy creatures.

Dr. Landman said the relatively few scientists who study the nautilus must overcome “a tremendous lack of knowledge” about its overall numbers and geographic range.

By contrast, modern consumers know far too much, he said: “You can see the shells polished and sold all over the place.”

The fossil record dates the ancestors of the nautilus to the late Cambrian period, 500 million years ago. Some grew to be true sea monsters, with gargantuan shells and big tentacles. Over eons, the thousands of species have dwindled to a handful.

The word “nautilus” comes from the Greek for boat. When the first shells arrived in Renaissance Europe, collectors were stunned: They saw the perfect spirals as reflecting the larger order of the universe.

Later on, Victorian homes displayed them as curios. In his famous 1858 poem “The Chambered Nautilus,” Oliver Wendell Holmes admired “the silent toil” that produced the “lustrous coil.” And in “Twenty Thousand Leagues Under the Sea,” Jules Verne created a watertight submarine of many compartments and christened it the Nautilus.

About those chambers: The creature periodically erects barriers inside its shell as it grows, leaving a series of unoccupied spaces behind. Like a submarine, the nautilus changes the amount of gas in the empty chambers to adjust its buoyancy. And it uses jet propulsion to swim.

To feed on fish and shrimp, it has as many as 90 small tentacles — and, like all cephalopods, a relatively large brain and eyes. The coiled shell can exhibit a nacreous luster or bands of bright color. The creature cannot go too deep lest its shell implode — like the hull of a submarine.

http://www.nytimes.com/2011/10/25/science/25nautilus.html?_r=2

Birch Mouse Ancestor Discovered in Inner Mongolia Is New Species of Rare 'Living Fossil'

Paleontologist Yuri Kimura, Southern Methodist University in Dallas,
identified a new species of birch mice, Sicista primus, from 17 tiny teeth.
A single molar is about the size of half a grain of rice. The teeth, however,
are distinctive among the various genera of rodents known as Dipodidae.
Cusps, valleys, ridges and other distinguishing characteristics on the
surface of the teeth are identifiable through a microscope.
(Credit: Yuri Kimura/Southern Methodist University)

ScienceDaily (May 25, 2011) — Tiny fossil teeth discovered in Inner Mongolia are a new species of birch mouse, indicating that ancestors of the small rodent are much older than previously reported, according to paleontologist Yuri Kimura, Southern Methodist University in Dallas.

Fossils of the new species were discovered in sediments that are 17 million years old, said Kimura, who identified the new species and named it Sicista primus to include the Latin word for "first."

Previously the oldest prehistoric ancestor of the modern-day birch mouse was one that inhabited Inner Mongolia 8 million years ago.

Adding 9 million years to the ancestry of the rodent family that includes birch mice and jumping mice distinguishes this genus, Sicista, as a "living fossil," Kimura said. That places the genus among some of the most unique rodents on earth -- those whose ancestry spans 2 to 3 times the average, she said.

Kimura identified Sicista primus from 17 tiny teeth, whose size makes them difficult to find. A single molar is about the size of half a grain of rice. The teeth, however, are distinctive among the various genera of rodents known as Dipodidae. Cusps, valleys, ridges and other distinguishing characteristics on the surface of the teeth are identifiable through a microscope.

"We are very lucky to have these," Kimura said. "Paleontologists usually look for bones, but a mouse is very tiny and its bones are very thin and fragile. The teeth, however, are preserved by enamel. Interestingly, small mammal teeth are very diverse in terms of their structure, so from that we can identify a species."

Kimura reported the new species in the scientific journal Naturwissenschaften. Images of the research and expedition are posted on the SMU Research flickr site (http://www.flickr.com/photos/52146845@N06/sets/72157626764403486/). SMUVideo's "Inner Mongolia yields 'living fossil'" featuring Kimura discussing the research is available on YouTube (http://www.youtube.com/watch?v=khkx11WlKaw).

An SMU doctoral student in the Huffington Department of Earth Sciences, Kimura was part of the international team that discovered the fossils during expeditions to Inner Mongolia in 2004, 2005 and 2007.

Microscopic evidence of a living fossil

The new fossils of Sicista primus from the Early Miocene age are also now the earliest known record of Sicista, the birch mouse genus that comprises 13 modern and 7 fossil species, said Kimura. As a result, Sicista now boasts the most ancient ancestry of the 326 genera in the largest rodent suborder to which it belongs, Myomorpha. The suborder includes laboratory mice and rats.

"The birch mouse is a rare case of a small mammal genus persisting from the Early Miocene without significant morphological changes," Kimura said in reporting the findings.

Rodents, both modern and prehistoric, rank as the most prolific mammals on earth. After the reign of dinosaurs, 65 million years ago, rodents evolved and dispersed worldwide during the Cenozoic, the "Age of Mammals." They comprise about 42 percent of all living mammals. Scientists know now that only 1.5 percent of modern rodent genera, however, go as far back as the Early Miocene or older.

"Diversity within a rodent genus is not unusual, but the long record of the genus Sicista, first recognized at 17 million years ago, is unusual," said Kimura. "The discovery of Early Miocene S. primus reveals that Sicista is fundamental to understanding how a long-lived genus persisted among substantially fast-evolving rodent groups."

Birch mice migrated from Asia to North America

Previously the record for the oldest species of Sicista belonged to an 8 million-year-old species identified in Eurasia, Kimura said.

In identifying the new species, Kimura also reverses the long-held hypothesis that ancestors of birch mice migrated from North America to Asia. That hypothesis has been based on a 14.8 million-year-old specimen from South Dakota, which was identified in 1977 as the separate rodent genus Macrognathomys. Kimura's analysis, however, concludes that Macrognathomys is actually Sicista. For that reason, she concluded, Sicista first inhabited the forests and grasslands of prehistoric Asia and then dispersed to North America via the Bering Land Bridge, Kimura said.

In a comparison of the molars and premolars from Macrognathomys and Sicista primus, Kimura reported finding 12 shared dental characteristics. In addition, phylogenetic analysis to identify evolutionary relationships indicated that both belong to the same genus, Sicista, she said.

Reconnaissance of earlier Central Asiatic Expedition localities yields small mammals

The teeth of Sicista primus were discovered in fine sediments gathered from Gashunyinadege, a fossil locality in the central region of Inner Mongolia.

Gashunyinadege is one of several fossil localities near Tunggur, a fossil site discovered in the 1920s by the Central Asiatic Expedition, which was led by Roy Chapman Andrews from the American Museum of Natural History.

Kimura is a member of an international scientific team sponsored by the Chinese Academy of Sciences Institute of Vertebrate Paleontology and Paleoanthropology and the Natural History Museum of Los Angeles County. The team's expeditions have been led by paleontologists Qiu Zhuding, IVPP; Wang Xiaoming, Natural History Museum of Los Angeles County; and Li Qiang, IVPP. Their expeditions retrace important classic localities, as well as prospect new fossil localities.

Kimura and other members of the team discovered the birch mouse fossils by first prospecting Gashunyinadege for small mammal fossils visible to the naked eye. Those fossils indicated the possibility of even smaller mammal fossils, so the team gathered 6,000 kilograms, more than 13,000 pounds, of Early Miocene sediment. Using standing water from recent rains, they washed the sediments repeatedly through continually smaller screens to separate out small fossils. Bags of concentrate containing particles the size of mouse teeth were returned to IVPP laboratories to hunt for fossils with a microscope.

The research was funded by the Institute for the Study of Earth and Man at SMU, Dallas Paleontological Society, Geological Society of America, Chinese Academy of Sciences Institute of Vertebrate Paleontology and Paleoanthropology.

http://www.sciencedaily.com/releases/2011/05/110524153420.htm

Crocs dispel 'living fossil' myth

Crocodiles can no longer be referred to as "living fossils", according to scientists.


Members of the crocodilian family have previously been thought to have changed little since prehistoric times.

However, new fossil analyses suggests that modern crocodilians actually evolved from a very diverse group.

Recently discovered ancient ancestors include small cat-like specimens, giant "supercrocs" and a pug-nosed vegetarian species.

Body structure
Modern crocodilians are adapted to aquatic environments with long snouts, strong tails and powerful jaws.

Yet contrary to popular belief, scientists now suggest that the basic body structure of crocodiles, alligators and ghariels evolved from a diverse group of prehistoric reptiles with different body shapes.

Since first discovering the unusual crocodilian Simosuchus clarki ten years ago, palaeontologists have worked to recover its fossil from Madagascar.


A decade later, a near-complete skeleton has been achieved, and its analysis has reignited discussion on the evolution of modern crocodilians.

"The skull and lower jaw in particular are preserved almost completely," says Nathan J. Kley, co-editor of the recent study in the Society of Vertebrate Paleontology Memoir.

"This, combined with high-resolution CT scans of the most exquisitely preserved specimen, has allowed us to describe the structure of the head skeleton - both externally and internally - in exceptional detail, including even the pathways of the tiniest nerves and blood vessels," he says.

Tank-like
S. clarki differs greatly to other crocodilians with a blunt snout, short tail and "tank-like" body.

With its short jaw and weak, leaf-shaped teeth, scientists suggest that the reptile would have been unable to take prey from the water's edge in the same way modern crocodiles do.


Instead, researchers propose that the ancient crocodile lived inland, feeding on vegetation in its semi-arid grassland habitat.

Researchers describe S. clarki as the "most bizarre" of a group of fossilised crocodilians thought to live around 66 million years ago.

This year, palaeontologists working in Tanzania also unearthed fossils of a tiny crocodile-like creature with teeth resembling those of mammals.

The "cat-like" crocodilian's unusual teeth differ from the conical teeth of modern crocodiles, used for ripping and tearing.

At the larger end of the scale, the preserved remains of an eight-tonne giant crocodile further fuelled debate when they were recovered in 2001.

By Ella Davies

Earth News reporter

Ancient seaweed is living fossil

By Matt Walker Editor, Earth News

Verdigellas: older than we thought

Ancient seaweed that have been found growing in the deep sea are "living fossils", researchers have reported.

The two types of seaweed, which grow more than 200m underwater, represent previously unrecognised ancient forms of algae, say the scientists.

As such, the algae could belong to the earliest of all known green plants, diverging up to one billion years ago from the ancestor of all such plants.

Details of the discovery are published in the Journal of Phycology.

"The algae occur in relatively deep marine waters - 210m, which is certainly deep for a photosynthetic organism," Professor Frederick Zechman told the BBC.

"They can be found in shallower water but typically under ledges in low light.

"They appear to possess special chlorophyll pigments that allow them to utilise the low intensity blue light found at depth."

Professor Zechman of California State University in Fresno, US, sampled the seaweeds with a team of researchers based across the US and in Belgium.

The algae had previously been identified. They belong to the scientific groups, or genera, called Palmophyllum and Verdigellas.

But Professor Zechman's team is the first to study their genetic make-up, and it is this research that has revealed their startling ancestry.

Green origins
Green plants in general belong to one of two groups, or clades.

One clade includes all land plants and the green algae with the most complex structures, known as charophytes or more commonly stoneworts.

The other clade, known as the Cholorophyta, comprises all other green algae.

Most studies have sought to determine what ancient plants gave rise to the land plants and stoneworts.

But little research has been done into the origin of the other green algae.

So Professor Zechman's team collected and studied Palmophyllum algae from New Zealand waters and Verdigellas from the western Atlantic Ocean.

These algae are unusual as they are multicellular, but their individual cells do not interact with each other in any meaningful way.

Instead, single cells sit in a gelatinous matrix, which can form complex shapes such as stalks.

The scientists analysed the DNA within the nuclei and chloroplasts in the algae's cells.

Instead of belonging to the Cholorophyta, the scientists discovered that both types of algae actually belong to a distinct new group of green plants, one that is incredibly ancient.


The algae are so different that they should be assigned their own Order, a high level taxonomic group, say the scientists.

What is more, "by comparing those gene sequences to the same genes in other green plants, we have discovered that these green algae are among the earliest diverging green plants... if not the earliest diverging lineage of green plants," Professor Zechman told the BBC.

"That would put them in the ball park of over a billion years old."

Plant progenitor
The discovery could "vastly change" our view of which green plant was the ancestor to all those we see today, he says.

That progenitor of green plants is currently thought to be a single-celled plant that had a tail-like structure called a flagellum, which allows the cell to move itself in water.

But no single-celled or flagellated algae of the types studied by Professor Zechman's team have been observed, suggesting the earliest green plants may not have had flagella after all.

Professor Zechman said the previously unrecognised ancient algae could be characterised as "living fossils", even though no actual fossils of such algae are known to exist.

The algae's ability to harness low light intensities allows them to grow in deep water habitats - and that may be the key to their incredible longevity.

At such depths, plants face less stress from the actions of waves, variations in temperature and fewer herbivores that might feed on them.