Paleontology, Biology, Evolution, Spinosaurus Aegyptiacus, the good stuff. (◡‿◡✿)
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  • palaeopedia:

    The chicken mimic, Gallimimus (1972)

    Phylum : Chordata
    Class : Reptilia
    Order : Saurischia
    Superfamily : Ornithomimoidea
    Family : Ornithomimidae
    Genus : O. bullaltus

    • Late Cretaceous (70 Ma)
    • 8 m long and 250 kg (size)
    • Mongolia (map)

    The feeding habits of ornithomimids have been controversial. The original describers thought Gallimimus preyed upon small animals, using its long arms as rakes to remove covering plant material on the soil. Later suggestions included omnivory and herbivory.

    In 2001 Norell et al. reported a specimen of Gallimimus (IGM 100/1133): a skull with soft tissue preservation. This specimen, as well as another new fossil skull of Ornithomimus, had a keratinous beak with vertical grooves projecting from the bony upper mandible. These structures are reminiscent of the lamellae seen in ducks, in which they function to strain small edible items like plants, forams, mollusks, and ostracods from the water. The authors further noted that ornithomimids were abundant in mesic environments, and rarer in more arid environments, suggesting that they may have depended on waterborne sources of food, possibly filter feeding. They noted that primitive ornithomimids had well developed teeth, while derived forms were edentulous and probably could not feed on large animals.

    One later paper questioned the conclusions of Norell et al. Barrett (2005) noted that vertical ridges are seen on the inner surface of the beaks of strictly herbivorous turtles, and also the hadrosaurid Edmontosaurus. Barrett also offered calculations, estimating how much energy could be derived from filter feeding and the probable energy needs of an animal as big as Gallimimus. He concluded that herbivory was more likely.

    (via tyrannosaurslair)

    rah-bop:

    I suddenly realized that I have a ton of sketches I’ve never bothered to scan. This is an old one but I still like it, though I drew it without reference so please pardon all the inaccuracies.

    Styracosaurs are probably my favorite ceratopsian …but it’s hard to pick just one favorite, honestly. There were so many really cool ones. 

    ink, watercolor

    (via tyrannosaurslair)

    alphynix:

    O is for Ornithomimus

    Ornithomimus was an ornithomimid theropod from the Late Cretaceous of North America, about 70 million years ago. It’s estimated to have reached around 3.8m in length (12’5”). Three specimens have been found with evidence of feathers: a juvenile with hair-like “fuzz”, and two adults with quill knobs on the arm bones. It seems that these dinosaurs developed wing-like feathers at sexual maturity, possibly using them for mating displays similarly to modern ostriches.

    The ornithomimids (“bird mimics”) were named for their superficial resemblance to large flightless birds. They had long legs adapted for speed, relatively small heads, and sloth-like arms. They were the most common small dinosaur in North America, suggesting they were probably herbivores — or possibly omnivores supplementing a plant diet with small prey.

    And they’re flocking this way.

    (via tyrannosaurslair)

    antediluvianechoes:

    Medusaceratops lokii by ~Olorotitan

    The ornithomimids strutted and scampered, dipped their beaks in the water, made tiny arrow-like footprints in the mud. They were all thin extremities pulled from white, feathery bodies. The slender necks and legs and tails and wings waltzed and swung from the torso and hips—ballerinas made of pendulums.

    The smell of rain was strong in the air. It had rained all night, drizzled in the morning, and new gray clouds rolled through the sky—but these were broken and looked to add little to the puddles. 

    The wet weather brought cool breezes and Medusaceratops relished them. On the open flats, the wind played freely, so the dinosaur wagged his heavy head to let the air winnow around his horns and behind his frill. August could be beautiful.

    (via tyrannosaurslair)

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