Dendrogramma

A new marine invertebrate, found off the coast of Australia, may be a survivor of Precambrian times:

Though no living animal closely resembles Dendrogramma, at least three fossils bear a striking resemblance. Albumares, Anfesta, and Rugoconites appear to also to have possessed a disk laced with forking, radiating channels.

Those enigmatic organisms have long captivated biologists with mysterious forms that look like whirls, fronds, and shrubs, and it's still debated whether they should be classified as animals. The life-forms are thought to have vanished more than 540 million years ago at the end of the Ediacaran period, just before a time of rapid animal evolution called the Cambrian explosion.

It is possible that Dendrogramma independently evolved a similar structure as a response to the same conditions as the three extinct species, a common phenomenon called convergent evolution.

"There is this most intriguing similarity to certain Ediacaran forms," Conway Morris says. "[But] I think the similarities are exactly that. They are intriguing rather than compelling."

Still, there is a chance that Dendrogramma are Ediacaran descendants, potentially making these animals the first to survive to modern times in recognizable form.

"If this is true," says study co-author Reinhardt Kristensen, an invertebrate zoologist at the University of Copenhagen, "then we have discovered animals which we'd expect to be extinct around 500 million years ago."

More pics from different angles.

Diagram from the original paper

On a related matter, some Ediacaran life-forms-- the earliest multicell animals on Earth-- were fractals.

Jeholornis

First dinosaur-birds with four wings, now one with two tails:

One of the oldest known birds, Jeholornis, lived in what is today China, along with a trove of other feathered dinosaurs discovered in the region over the last decade. It was also thought to sport only a long fan-feathered tail at its back end. Now, however, paleontologists are claiming discovery of a second tail frond adorning the bird.

"The 'two-tail' plumage of Jeholornis is unique," according to the study, which was led by Jingmai O’Connor of the Chinese Academy of Sciences in Beijing. The report of the discovery of the tail frond was published in the Proceedings of the National Academy of Sciences.

Of 11 Jeholornis fossils that retain evidence of ancient plumage, 6 have signs of this frond of 11 feathers, which would have jutted above the bird's back at a jaunty, upright angle in a "visually striking" manner, according to the study.

Mesozoic coastlines and modern politics

Virgil once wrote, "Felix qui potuit rerum cognóscere causas"-- "Happy is the one who knows the causes of things," and I am certainly happy to know the cause of a band of Democratic-voting counties in the otherwise mostly Republican Deep South, namely that this geographical region used to be the coastline of an ocean that split North America during Cretaceous times. Intermediate links in the causal chain are plankton, chalk, cotton, and slavery:

During the Cretaceous, 139-65 million years ago, shallow seas covered much of the southern United States.   These tropical waters were productive–giving rise to tiny marine plankton with carbonate skeletons which overtime accumulated into massive chalk formations.  The chalk, both alkaline and porous, lead to fertile and well-drained soils in a band, mirroring that ancient coastline and stretching across the now much drier South....
Over time this rich soil produced an amazingly productive agricultural region, especially for cotton.  In 1859 alone a harvest of over 4,000 cotton bales was not uncommon within the belt. And yet, just tens of miles north or south this harvest was rare.  Of course this level of cotton production required extensive labor...
As Washington notes further in his autobiography, “The part of the country possessing this thick, dark, and naturally rich soil was, of course, the part of the South where the slaves were most profitable, and consequently they were taken there in the largest numbers."

Ctenoimbricata

Believe it or not, this odd prickly creature, which lived during the Cambrian era, is a primitive echinoderm:

Echinoderms (starfish, sea urchins, sea cucumbers, crinoids, etc.) are well-known for their pentamerous (5-fold) radial symmetry. ...Many living echinoderms pass through a bilateral larval stage, evidence for the well-worn adage "ontogeny recapitulates phylogeny" (also known as the Biogenic Law, which as a general hypothesis is now largely unaccepted). However, no fossil evidence - that is, an actual bilateral echinoderm - has ever been found (although a few asymmetric fossil echinoderms are known). Until now. Samuel Zamora, of The Natural History Museum in London, and colleagues have just described Ctenoimbricata spinosa, a new genus and species from the Murero Formation (earliest middle Cambrian Period) in northeastern Spain.

Via This View of Life.

Siphusauctum

Over a century after its initial discovery, the Burgess Shale continues to be a treasure trove of bizarre Cambrian fossils, most recently this tulip-shaped creature:

Reconstruction by Marianne Collins

“Most interesting is that this feeding system appears to be unique among animals. Recent advances have linked many bizarre Burgess Shale animals as primitive members of many animal groups that are found today, but Siphusauctum defies this trend.  We do not know where it fits in relation to other organisms,” said lead author O’Brien.

Via Life Before the Dinosaurs.

Fossils from Darwin's cabinet

A "treasure trove" of fossils - including some collected by Charles Darwin - has been re-discovered in an old cabinet.
The fossils, lost for some 165 years, were found by chance in the vaults of the British Geological Survey HQ near Keyworth, UK.
...
The find was made by the palaeontologist Dr Howard Falcon-Lang.
Dr Falcon-Lang, who is based in the department of earth sciences at Royal Holloway, University of London, spotted some drawers in a cabinet marked "unregistered fossil plants".
"Inside the drawer were hundreds of beautiful glass slides made by polishing fossil plants into thin translucent sheets," Dr Falcon-Lang explained.
"This process allows them to be studied under the microscope. Almost the first slide I picked up was labelled 'C. Darwin Esq'."

From BBC News. The Daily Mail has more pictures.

Nyctosaurs

An illustration by paleo-artist Mark Witton, showing some very odd pterosaurs: 

 

Found via this old post on Tetrapod Zoology, from which I also learned that baby pterosaurs are called "flaplings."

Characodictyon

This is an electron microscope image of a tiny fossil from the Precambrian era, the shell of a microbe (somewhat resembling modern radiolaria). It may be the oldest example of armor on a living creature. 

Image from Live Science. 

Predators of the Cambrian

A cool CGI reconstruction of Cambrian-era creatures found fossilized at the Burgess Shale:

The two large swimming predators are Hurdia and its cousin Anomalocaris-- the latter of which had very sharp eyes:

The fossils represent compound eyes -- the multi-faceted variety seen in arthropods such as flies, crabs and kin -- and are amongst the largest to have ever existed, with each eye up to 3 cm in length and containing over 16,000 lenses.
The number of lenses and other aspects of their optical design suggest that Anomalocaris would have seen its world with exceptional clarity whilst hunting in well-lit waters. Only a few arthropods, such as modern predatory dragonflies, have similar resolution.
The existence of highly sophisticated, visual hunters within Cambrian communities would have accelerated the predator-prey 'arms race' that began during this important phase in early animal evolution over half a billion years ago

Vowels and vestigial air sacs

Over millions of years, changes to our vocal organs have allowed us to produce a rich mix of sounds. One such change was the loss of the air sac - a balloon-like organ that helps primates to produce booming noises.

All primates have an air sac except humans, in whom it has shrunk to a vestigial organ. ...

To find out how this changed the sounds produced, Bart de Boer of the University of Amsterdam in the Netherlands created artificial vocal tracts from shaped plastic tubes. Air forced down them produced different vowel sounds, and half of the models had an extra chamber to mimic an air sac.

De Boer played the sounds to 22 people and asked them to identify the vowel. If they got it right, they were asked to try again, only this time noise was added to make it harder to identify the sound. If they got it wrong, noise was reduced.

He found that those listening to tubes without air sacs could tolerate much more noise before the vowels became unintelligible.

The air sacs acted like bass drums, resonating at low frequencies, and causing vowel sounds to merge...

Observations of soldiers from the first world war corroborate de Boer's findings. Poison gas enlarged the vestigial air sacs of some soldiers, who are said to have had speech problems that made them hard to comprehend.

From New Scientist.

Tiny bird, giant ant

The above figure, from Archibald et al. (2011), shows a rufous hummingbird Selasphorus rufus alongside the newly described early Eocene giant ant Titanomyrma lubei. This fossil comes from the American Green River Formation, in present-day Wyoming. At 51 mm in length, this is one of the largest known ants.

Information and picture from Catalogue of Organisms.

This odd juxtaposition of creatures demonstrates a principle of adjectival semantics: size is relative. There's no contradiction in saying that a "tiny bird" is the same size as a "giant ant." A tiny dinosaur could be far bigger than either, and a giant virus far smaller.

Mythical taxonomy

From Curiosities of Biological Nomenclature, some interesting taxonomic names with their roots in classical mythology: 

• Achelousaurus horneri Sampson, 1995 (ceratopsian dinosaur). This hornless ceratopsian evolved from horned ancestors. It was named for Achelous, a Greek river god whose horn was broken in a battle with Heracles. The species name (for paleontologist Jack Horner) replaces the lost horn. [J. Vert. Paleo. 15(4)]

• Thermarces cerberus Rosenblatt and Cohen, 1986 (Eelpout fish) from the Galapagos rift vents. Cerberus was the three-headed dog that guarded the gates of Hades.

• Cyclops (copepod) with a single median eye.

• Daedalosaurus Carroll, 1978 (Late Permian gliding reptile from Madagascar) and Icarosaurus Colbert, 1970 (Upper Triassic gliding reptile from New Jersey), after Daedalus and Icarus.

• Damocles Lund, 1986 (Carboniferous shark) The males had an elaborate projection from the back that ended poised over its head.

• Gorgonocephalus medusae (basket star) The basket star looks like a mass of serpents. Medusa was the most famous of the Gorgons, which had serpents for hair.

• Pegasus Linnaeus, 1758 (seamoth fish)

• Amoeba proteus (amoeba), so named because Proteus had the ability to change form.

• Sisyphus Latreille, 1807 (dung beetle) Named after a king condemned in Hades to roll an immense boulder uphill, only to have it inevitably break free and roll down again, this beetle makes and rolls large balls of dung with greater success.

• Talos Zanno et al., 2011 (birdlike theropod dinosaur) Named for a winged bronze giant of Greek mythology, which could run extremely fast and which succumbed to an ankle wound. The name is also a pun on "talon".

Another particularly lovely name in this vein belongs to Prodryas persephone, a fossil butterfly whose species name refers to the queen of the underworld. (The naturalist who named Prodryas gave similarly allusive names to two other fossil butterflies: Lithopsyche styx and Jupiteria charon.)

Prehistoric iridescence

Although the original colors of the fossil moths were not preserved, the researchers were able to reconstruct them because the tiny color-producing patterns in the moth scales were intact. "The level of detail preserved in the scales of the fossil moths is just spectacular", said McNamara. The fossil moths owe their color to a stack of layers inside the scales. These layers form a fossil multilayer reflector, which usually produces iridescent colour that changes depending on viewing angle. But other details of the fossil scales suppressed this effect, producing instead muted colors. "The moths basically wanted to appear the same colour from different angles – they didn't want flashy iridescence" said McNamara.

Full story at Physorg.

Also, iridescence in animals may go back as far as the Cambrian era:

At different times of day and different viewing angles, the marine creatures [Wiwaxia, Canadia, and Marella] would have glowed blue, red, yellow, or green. Since the evolution of these worms coincides with the first appearance in the fossil record of animals with eyes, such as trilobites, the twinkling colors may have warned predators to avoid these armored, and perhaps unpalatable, animals.

When I was a child, the color of prehistoric animals was presented as an unknowable mystery. But now, discoveries like these are commonplace-- but no less wonderful for it.  

Raven-feathered Archaeopteryx

For years, palaeontologists have speculated about Archaeopteryx's colour scheme, without knowing for sure. Artists have painted it in every shade from tan and rusty brown, to bright greens and blues.

All this speculation could soon end, with new ways to detect prehistoric colours. 

...The feather [shown above] was most probably black. While the full colour pattern of Archaeopteryx has yet to be uncovered, Carney noted that melanosomes on the black feather have structural properties which may have strengthened the feathers for the demands of flight. The miniscule structures which hide the secrets of prehistoric colour were not just for show.

From New Scientist. Other prehistoric birds and feathered non-avian dinosaurs were more colorful, and some later fossil feathers display iridescence.

Fossil silky lacewing

This insect, Undulopsychopsis alexi, would have fluttered among the dinosaurs.

Image from Science Daily.

Dinofeathers in amber

 

An amazing find from Alberta, Canada:

Feathers believed to be from dinosaurs have been found beautifully preserved in Alberta amber.
The primitive, hair-like feathers known as protofeathers likely belonged to theropods — dinosaurs similar to tiny Tyrannosaurus rexes — that roamed the swampy forests of Alberta 80 million years ago, said Alexander P. Wolfe, a University of Alberta earth sciences professor who co-authored the research published Thursday in Science.
...The feathers are preserved down to the pigments that show what colour they are and microscopic details of their structure.
Based on the fact that the protofeathers were just single filaments or clumps of filaments, just two centimetres long, the researchers concluded "these had nothing to do with flight," Wolfe said.
Instead, he believes they were used to keep the dinosaurs warm.

Another of the Canadian specimens. Image source.

Lake sharks of Triassic Kyrgyzstan

Several 230-million-year-old teeth and egg capsules uncovered at a fossil site in southwestern Kyrgyzstan suggest hundreds of young sharks once congregated in a shallow lake, a new study says.
Called hybodontids, the animals were likely bottom feeders, like modern-day nurse sharks.
Mothers would've attached their eggs to horsetails and other marshy plants along the lakeshore. Once born, the Triassic-era babies would've had their pick from a rich food supply of tiny invertebrates, while dense vegetation offered protection from predators.

Image (showing a beautiful fossil egg case) and information from National Geographic.

Eoandromeda octobrachiata

Near the roots of the tree of life, we find a living spiral:

A 580-million-year-old fossil is casting doubt on the established tree of animal life. The invertebrate, named Eoandromeda octobrachiata because its body plan resembles the spiral galaxy Andromeda, suggests that the earliest branches in the tree need to be reordered, say the authors of study in Evolution and Development.
The researchers, led by paleontologist Feng Tang of the Chinese Academy of Geological Sciences in Beijing, believe that Eoandromeda is the ancient ancestor of modern ocean dwellers known as comb jellies — gelatinous creatures similar to jellyfish, but rounder and with eight rows of iridescent paddles along their sides. If they are right, it would be the oldest known fossil of a comb jelly. And that would support a rewrite of the animal tree. 

From Nature, via The Book of Barely Imagined Beings.

Ammolite

This colorful, rare gemstone comes from the fossil shells of prehistoric ammonites. Sometimes there are found whole shells composed of ammolite.

"Straight-sided towers of lenses... "

The eye of the trilobite Erbenochile.