Fossils provide unparalleled peeks into Earth’s living history in the form of mineralized bones and shells, body imprints and even piles of poop. There always seems to be another twist and turn in evolution’s creations awaiting trowel-wielding scientists. From dinosaur-eating snakes to shark-bitten piles of crocodile dung (seriously), dig up some of this year’s best finds with us in celebration of National Fossil Day. Squashed Jurassic Spider This almost perfectly preserved spider fossil from China (one of two) dates back 165 million years ago, to the middle Jurassic era. Known as Eoplectreurys gertschi, the spiders are older than the only two other specimens known by around 120 million years and rival their detail, paleontologists said in February. Spider fossils are tough to find because their soft bodies don’t preserve well. Thanks to fine volcanic ash, however, this spider was squashed without breaking up its delicate exoskeleton. Image: Paul Selden

Dinosaur-Eating Snakes Calling it a “stunning, once-in-a-lifetime find,” paleontologists reported a 67 million-year-old fossil of a snake coiled around dinosaur eggs and a hatchling -- the first-ever evidence of snakes eating dinosaurs.

Geologist Dhanajay Mohabey of the Indian Geological Survey first unearthed the fossil 26 years ago in a limestone outcropping in the northwestern Indian village of Dholi Dungri. It wasn’t until 2001, however, that he took a second look and found a snake coiled around a broken egg, with a hatchling and two other eggs nearby. Images: 1) Reconstruction of scene, Sculpture by Tyler Keillor and original photography by Ximena Erickson (image modified by Bonnie Miljour). 2) Wilson et al./PLoS Biology

Shark-Bitten Crocodile Poop Yes, you read that correctly. Coprolites -- hunks of fossilized poop -- can reveal the diets and behaviors of ancient animals, but this one is plain weird. Discovered on a beach along the western shore of Chesapeake Bay, researchers don’t think the responsible shark was hungry for the fecal matter. Instead, the now 15-million-year-old poop was probably still inside the unsuspecting crocodile’s intestines when bitten. Image: Stephen Godfrey

New Primate Relative Two 1.9 million-year-old South African skeletons (discovered with some help from Google Earth) have added a new and intriguing member to the primate family. Dubbed Australopithecus sediba, the specimens have long legs and a protruding nose -- features common to Homo, the genus that eventually spawned humans. The creatures also had extra-long forearms and flexible feet. Paleontologists disagree over whether A. sediba is a direct human ancestor or just looks like one. In either case, the fossils provide a rare opportunity for examining a period shrouded in paleontological mystery. Image: Lee Berger/Science

Giant Forgotten Fishes Misidentified fossils that were forgotten and later rediscovered in museums revealed two new species of giant, filter-feeding fish that swam Earth’s oceans for 100 million years. The behemoths, known as Bonnerichthys gladius and Rhinconichthys taylori, grew to 30 to 50 feet long and occupied the ecological niche now filled by whales and whale sharks. That ancient niche was thought to be empty, and such fish to be a short-lived evolutionary bust, but paleobiologists reported that the re-identified specimens show the creatures “had a long and illustrious evolutionary history.” Images: 1) Robert Nicholls, 2) Bonnerichthys jawbones and forefin/Matt Friedman

Ancient Mystery Organisms A collection of 2.1-billion-year-old fossil organisms announced this year may be the earliest known example of complex life on Earth. The fossils are flat discs almost 5 inches across, and have scalloped edges and radial slits. Paleobiologists think they were either complex colonies of single-celled organisms or early animals. The specimens predate the first truly multicellular organism, called Grypania spiralis, which appeared in the fossil record 1.4 billion years ago. But they don’t beat single-celled organisms that emerged about 3.4 billion years ago. Image: Abderrazak El Albani and Arnaud Mazurier

Giant Penguins What was 5 feet tall, ate fish and was grey-and-red all over? According to a paper published this year, it’s Inkayacu paracasensis -- a previously unknown, 36-million-year-old penguin from Peru. The creature weighed in at an estimated 120 to 130 pounds, or roughly twice as heavy as the modern-day emperor penguin. Like its giant cousin Icadyptes, it had an hyper-elongated bill which it used to snap up fish in the ancient equatorial sea. Unlike any other previously unearthed penguin fossils, however, this specimen had feathers preserved along a forelimb, showing the ancient penguins had streamlined flippers for propelling themselves through the water like their modern-day relatives. Image: Julia A. Clarke/Science Via Brian Switek/Laelaps