If you dug up a fossil that looked like a circular saw blade made of teeth, you’d be forgiven for being a little confused. Was it some sort of toothy nautilus? A relic of a dinosaur’s carpentry shop?
When Helicoprion (meaning “spiral saw”) was first discovered in 1899, its whorl of teeth was one of the few things identified. Even though there were few skeletal clues, it was quickly decided that these teeth were from a cartilaginous fish. But where did these “teeth” fit in? On the body? Some freaky mouth appendage?
Over a century of confusion followed, but recent work using X-ray analysis of fossil specimens has all but confirmed that this fish used a spiral-fed whorl of teeth, constantly regrowing as today’s sharks do, to catch soft prey like squid, 270 million years ago. It’s actually not a shark at all, but a ratfish, a branch of cartilage-skeletoned fish that branched from sharks in prehistoric times.
Check out more great analysis by Brian Switek at Laelaps. He also features even more great art by Ray Troll, a Helicoprion aficionado who did the image at top.
Fossils of Enigmatic Sea Creatures Surface
by Sid Perkins
New fossil finds reveal that an enigmatic seafloor dweller first described more than a decade ago was armored and much larger than its modern-day kin. Cotyledion tylodes had a goblet-shaped body that surrounded a U-shaped gut (dark feature in fossil at left; arrows denote flow of food), and the animal spent its life anchored to the seafloor or to hard objects that had settled there, such as the molted exoskeletons of trilobites (artist’s representation at right). C. tylodes was first described in 1999 based on a couple of fragmentary fossils unearthed from 520-million-year-old rocks in southern China.
Previously, some scientists have proposed that the tentacled creatures were related to cnidarians, a group that contains jellyfish. But analyses of the new fossils—hundreds of well-preserved specimens extracted from the same ancient rocks—reveal that the animals belong to a group called entoprocts, aquatic creatures that attach to surfaces and filter their food from passing currents, the researchers report online today in Scientific Reports…
(read more: Science NOW)
(images: Zhifei Zhang et al., Scientific Reports)
Ammonite Fossil - carbon dust on Bristol vellum 4x
This week’s BrainSmudge theme is Scientific Illustration. And while today focuses on Astronomy (and Marine Biology was on Saturday), this very cool bit was shared with me and I am compelled to post it. Kind of Paleontology and Marine Biology in one! ”Paleontologists discovered the remains of the creature, called a Belemnotheutis antiquus, during a dig at a Victorian excavation in Trowbridge, Wilts.
They cracked open what appeared to be an ordinary looking rock only to find the one-inch-long black ink sac inside.
After realising what they had stumbled across, they took out a small sample of the black substance and ground it up with an ammonia solution.
Remarkably, the ink they created was good enough to allow them to draw the squid-like animal and write its Latin name.
Other examples of sea creature were also discovered giving the scientists an excellent opportunity to study the species.”
There’s something not quite right about drawing a squid with it’s own ink, even if it is a fossil, but it’s stunning that you can.
West Indian Ocean Coelacanth, Latimeria chalumnae.
Elephant’s sixth ‘toe’ discovered
By Rebecca Morelle [Science reporter, BBC News]
A mysterious bony growth found in elephants’ feet is actually a sixth “toe”, scientists report.
For more than 300 years, the structure has puzzled researchers, but this study suggests that it helps to support elephants’ colossal weight.
Fossils reveal that this “pre-digit” evolved about 40 million years ago, at a point when early elephants became larger and more land-based.
Lead author Professor John Hutchinson, from the UK’s structure and motion laboratory at the Royal Veterinary College, said: “It’s a cool mystery that goes back to 1706, when the first elephant was dissected by a Scottish surgeon.”
"Anyone who has studied elephants’ feet has wondered about it. They’ve thought: ‘Huh, that’s weird,’ and then moved on," he added.
But Prof Hutchinson and colleagues used a combination of CT scans, histology, dissection and electron microscopy to solve the puzzle.
The researchers said the structure was made of bone, although bone with a highly irregular and unusual arrangement.
But closer examination also revealed that it showed a strong similarity with an unusual bone that is found in the front feet of pandas.
This bone - which is not quite an extra digit, but does the job of one - helps the panda to grip bamboo, and is called the panda’s “thumb” or “sixth finger”. Moles too have a bone masquerading as an extra digit, which helps them to dig.
Read More: BBC
The oldest known whale to ply the Antarctic has been found, scientists say.
A 24-inch-long (60-centimeter-long) jawbone was recently discovered amid a rich deposit of fossils on the Antarctic Peninsula.
The creature, which may have reached lengths of up to 20 feet (6 meters), had a mouthful of teeth and likely feasted on giant penguins, sharks, and big bony fish, whose remains were also discovered with the jawbone.
The early whale swam polar waters during the Eocene period, some 49 million years ago. Its age suggests fully aquatic whales evolved from their mammalian ancestors more rapidly than previously thought, said researcher Thomas Mörs, paleozoologist at the Swedish Museum of Natural History.
Based on 53-million-year-old fossils of whale-like, semi-aquatic mammals, scientists had thought mammals gave rise to whales in a process that took 15 million years. The new find suggests it took just 4 million years.
Burgesscomplg (by Goniagnostus)
The color version of the Burgess Shale community that John Whorral and I created together.
I fell in love with the Burgess Shale at Uni…
- Pliny the Elder (d. 79 AD. near Pompeii) called fossils of these animals ammonis cornua (“horns of Ammon”) because the Egyptian god Ammon (Amun) was typically depicted wearing ram’s horns. Often the name of an ammonite genus ends in -ceras, which is Greek for “horn”.
I love ammonites!
The Man Who Swims With Coelacanths
More than seven decades later, the words have the same urgency as when they rolled off Marjorie Courtinay-Latimer’s telegraph machine and into history:
MOST IMPORTANT PRESERVE SKELETON AND GILLS = FISH DESCRIBED.
Courtinay-Latimer was the young curator of a natural history museum on South Africa’s east coast. The message came from J.L.B. Smith, an icthyologist to whom she’d turned when, shortly before Christmas in 1938, local fishermen brought her a fish unlike any they’d ever seen.
Caught at a depth of 240 feet, it was five feet long, covered in bony scales and had fins reminiscent of legs. Courtinay-Latimer immediately sent a sketch to Smith, who thought it looked like a coelacanth. There was just one catch: Coelacanths were extinct, and had been for 70 million years.
The sketch sent by Marjorie Courtinay-Latimer to J.L.B. Smith. South African Institute for Aquatic Biodiversity
Smith’s famous cable came too late, as Courtinay-Latimer didn’t have an aquarium large enough to preserve the fish. But even as they despaired, it was just weeks before another arrived.
Far from being extinct, coelacanths were actually caught with some regularity by native fishermen of the Comoros Islands, on whose rocky undersea slopes they’d lived since swimming with dinosaurs. The coelacanths of the Comoros Islands, along with another population discovered in Indonesia, are now celebrities of the animal kingdom, and nobody has spent more time with them than Hans Fricke.
In 1986, the German explorer and then-freelance photographer convinced a magazine editor to send him and a submarine to the Comoros. Since then he’s led more than 400 dives, helping to produce much of what is now known about coelacanths. After the publication of his latest work, published in Marine Biology and entitled “The population biology of the living coelacanth studied over 21 years,” Wired.com talked to Fricke about his time with the mysterious, magnificent creatures.