12 incridicle Fossil Finds in 2015 - 600 M years Ago

Every year, paleontologists dig up discoveries that completely reshape our understanding of life on Earth. But 2015 was something special. From a creature barely bigger than a pinhead to a terrifying prehistoric bird, the fossil finds of that year told a story spanning nearly 600 million years. Here are 12 of the most remarkable ones.

600 Million Years Ago — The Oldest Sponge Ancestor

Courtesy of Zongjun Yin

Barely the size of a pinhead, Eocyathispongia qiania had tubular chambers and surface cells strikingly similar to those of modern sponges — making it one of the earliest known animal ancestors. (SN: 4/4/15, p. 12)

460 Million Years Ago — The Earliest Sea Scorpion

J. Lamsdell

Found in an ancient meteorite impact crater in Iowa, Pentecopterus decorahensis was a genuine sea monster — up to 1.7 meters long with bristly, serrated limbs built for grabbing prey. (SN: 11/14/15, p. 5)

385 Million Years Ago — A Fish That Could Do Push-Ups

Neil Shubin

New analysis of Tiktaalik roseae — the famous "fishapod" transitional species — revealed that its hind fins were much stronger and more limb-like than previously thought, suggesting it could prop itself up and move on land earlier than expected. (SN: 1/24/15, p. 8)

~230 Million Years Ago — T. rex's Plant-Eating Cousin

Chilesaurus diegosuarezi had the skeleton of a theropod dinosaur but the blunt, plant-eating teeth of a herbivore — proof that not all T. rex relatives were carnivores. (SN: 5/30/15, p. 8)

~145 Million Years Ago — A Tiny Dinosaur With Wings

The crow-sized dinosaur Yi qi had bizarre bat-like wing membranes supported by a long bone extending from its wrists — a type of flight apparatus never seen before in dinosaurs. (SN: 5/16/15, p. 6)

~100 Million Years Ago — A Dinosaur Tail in Amber

A chunk of Burmese amber was found to contain a small section of a feathered dinosaur tail, preserving individual feathers, soft tissue, and even traces of pigment — an astonishing window into Cretaceous life. (SN: 12/31/15)

~65 Million Years Ago — New Evidence on Dinosaur Extinction

Drilling into the Chicxulub impact crater off Mexico's Yucatan Peninsula provided new details about the asteroid impact that ended the Cretaceous period — and wiped out the non-avian dinosaurs. (SN: 12/12/15, p. 8)

~47 Million Years Ago — Ida Gets a Rival

A nearly complete primate skeleton found in a German fossil site provided new evidence about early primate evolution, suggesting our deep ancestors were more diverse and widespread than previously understood. (SN: 6/13/15, p. 10)

~20 Million Years Ago — Ancient Whale Cousin

New fossils of ancient whales revealed surprising flexibility in the evolutionary transition from land to sea, showing that whale ancestors experimented with many different body plans before settling into today's familiar forms. (SN: 2016)

~11.6 Million Years Ago — Laia, the Gibbonlike Ancestor

Pliobates cataloniae, nicknamed "Laia," challenges the idea that apes descended from large, gorilla-sized ancestors. This cat-sized primate suggests today’s apes evolved from smaller, gibbonlike creatures. (SN: 11/28/15, p. 10)

~3.5 Million Years Ago — Terror Bird

F. Degrange

Llallawavis scagliai was a South American predator standing 1.2 meters tall, with a beak reinforced like a hatchet for stunning prey on impact. (SN: 5/2/15, p. 11)

~3 Million Years Ago — Little Foot Revealed

After more than two decades of painstaking excavation in a South African cave, researchers unveiled "Little Foot," one of the most complete Australopithecus skeletons ever discovered — offering new insight into our early hominin relatives. (SN: 2015)

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Source: Science News

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Genetic Researchers Grow A Fish That Has Legs !!!

Zebrafish Limbs Freitas et al., Developmental Cell

The fossil record has a lot of strange stories to tell about the evolution of life on Earth, and one of the strangest is how life moved from sea to land. Though clues from the record give the rough outlines of the story--limbs grew from fins in a series of stages in which fins grew longer and narrower--scientists are still filling in the details, trying to determine what genetic changes might have allowed the limbs to grow.





One of the best ways to learn those details is to reproduce the changes that occurred some 400 million years ago--to virtually go back in time and alter the development of the land-goer's living ancestors and see what happens.

Which is what biologist Renata Freitas and colleagues were up to when they added some extra Hoxd13--a gene known to play a role in distinguishing body parts during embryological development-- to the tip of a zebrafish embryo's fin, and watched as the developing fin kept growing:

Comparison of normal and genetically modified zebrafish: Freitas et al., Developmental Cell

Those round objects on the ends of the embryo's fins look a lot like autopods, the multifinger proto-extremities that evolved from lobe-finned fish, allowing life's first foray on to land. Here's a diagram from the researcher's paper, showing the changes that the extra dose of Hoxd13 allowed:

Adding Hoxd13: Freitas et al., Developmental Cell

Their lab findings led the researchers to hypothesize that the secret to limb development may have been a new element in some lobe-finned fish's DNA. When present, this DNA element would have helped turn on the Hoxd13 gene on the fish embryo's fins, leading them to lengthen and grow into limbs.
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