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Episode 366: T. rex cranium power, tooth association, and operating pace

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    Episode 366 is all about Saltopus, a Triassic dinosauriform from Scotland which was initially considered a theropod.

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    On this episode, we focus on:

    Information:

    • We focus on the Biomechanics, Taphonomy, & Quantitative Strategies periods from the Society of Vertebrate Paleontology annual assembly supply
    • A brand new juvenile hadrosauroid, Parrosaurus/Hypsibema missouriensis, was present in Missouri supply
    • A puzzle of 4 Stegosaurus photos was misprinted so there was no distinction to search out between the photographs supply

    The dinosaur of the day: Saltopus

    • Dinosauriform that lived within the Late Triassic in what’s now Scotland (Lossiemouth Sandstone Formation )
    • First considered a theropod
    • Seems to be like different early dinosaurs, small, slender, and bipedal
    • Described as cat-sized
    • Estimated to be 31 to 39 in (80 to 100 cm) lengthy and weigh about 2.2 lb (1 kg)
    • Later estimates of about 20 in (50 cm) lengthy and about 0.2 lb (110 g)
    • Had some very slender components, like neural spines lower than 1 mm large
    • Had an extended tail, about half its physique size was the tail
    • Had 5 fingers on its arms (the fourth and fifth fingers have been decreased/brief)
    • Had comparatively lengthy legs
    • Had comparatively brief arms
    • Doable that Saltopus hunted bugs and small vertebrates, however no cranium or tooth have been discovered
    • Sort species is Saltopus elginensis
    • Discovered round Elgin, Scotland
    • Discovered by William Taylor, who confirmed it to Friedrich von Huene in 1909. Taylor was a well-known fossil collector within the space from 1890 to 1920
    • Named by Friedrich von Huene in 1910
    • Genus title means “hopping foot”
    • Huene thought Saltopus was a frog-like hopper and mentioned that the “skinny and versatile tail could possibly be no hindrance to hopping regardless of its size”
    • Most scientists assume Saltopus was a bipedal runner that used its lengthy tail to assist steadiness
    • Species title refers to Elgin (the Permian and Triassic fossils discovered within the sandstone deposits in and across the city of Elgin, in Moray, Scotland are known as the Elgin Reptiles)
    • Holotype consists of elements of the vertebral column, forelimbs, pelvis, and hindlimbs (no cranium)
    • In 2010, in keeping with Michael Benton, who with a staff in 2010 re-analyzed the sort specimen of Saltopus, “The preservation of the Saltopus specimen is modest to poor.”
    • Preserved as half and counterpart slabs that present the center a part of the skeleton, mendacity belly-down
    • “The fossil is represented, as is typical of specimens from the Lossiemouth Sandstone Formation, by hollows within the medium-grained yellow sandstone; basically all bone materials has vanished.”
    • Huene wrote: “A lot of the bones are become brown iron sand”
    • In different phrases, the specimen is thought from the areas left within the rock the place the bones had dissolved
    • Skeleton consists of vertebral column, left forelimb, pelvic area, hindlimbs (sprawled to the edges) and a part of the tail that attaches to the physique (24 caudal vertebrae)
    • Some scaly pores and skin additionally preserved
    • Benton and others used casts, X-rays, and CT scans to reexamine the fossil
    • Many casts and molds have been made
    • Debates about whether or not it was a dinosaur or dinosauromorph, primarily based on the specimen being incomplete and poorly preserved
    • Had two sacral vertebrae (was dinosaurs had greater than two sacral vertebrae, however later dinosaurs akin to Herrerasaurus have been discovered to have two sacral vertebrae)
    • Based mostly on cladistic evaluation, Benton and others discovered Saltopus to be a dinosauromorph due to the decreased fourth and fifth digits on its arms, in addition to different options of the bones
    • Additionally discovered it to nonetheless be a sound taxon primarily based on distinctive characters
    • Will be the closest relative of true dinosaurs (a typical dinosaur ancestor)
    • In 2017, Matthew Baron and others proposed that dinosaurs be divided into the clades Ornithoscelida and Saurischia (as a substitute of Ornithischia and Saurischia)
    • Saurischia had lizard-like hip bones and included theropods and sauropods, Ornithischia had bird-like hop bones and included ceratopsians and thyreophorans
    • Interviewed Matt Baron in episode 145
    • Discovered there have been carnivores in each the clades Ornithoscelida and Saurischia, and the sister taxon to Dinosauria, Silesauridae, largely consists of herbivores. This may occasionally imply the frequent ancestors of each have been omnivores, and omnivorous ancestors lived in each the northern and southern hemispheres
    • Baron mentioned it is probably not potential to know for positive the origin of dinosaurs however they could have originated within the northern hemisphere, not the southern hemisphere as beforehand thought (one chance is Saltopus)
    • Not everybody agreed that Saltopus was a very good candidate for a dinosaur frequent ancestor (lived about the appropriate time however not the most effective fossils to work with)
    • Additionally, one other genus, Agnosphitys cromhallensis, present in England, was discovered to be a basal member of Silesauridae. Along with Saltopus, additionally helps present dinosaurs and silesaurids might have originated in Laurasia
    • In 2018, Matthew Baron and Megan Williams redescribed the holotype of the Late Triassic dinosauriform Caseosaurus crosbyensis, and located that Caseosaurus, together with Saltopus, have been herrerasaurs and that herrerasaurs have been a sister taxon of dinosaurs (not dinosaurs themselves)
    • Makes all of the herrerasaurs non-dinosaurian dinosauriforms
    • Wrote that their phylogenetic evaluation, “together with different latest analyses of early dinosaurs, pulls aside what stays of the “conventional” group of dinosaurs collectively termed saurischians right into a polyphyletic assemblage and implies that Dinosauria must be thought to be composed solely of Ornithoscelida (Ornithischia + Theropoda) and Sauropodomorpha.”
    • Prompt reviving the title Herrerasauria for the clade (any and all taxa within the herrerasaur lineage).
    • Additionally discovered Silesauridae to be the sister taxon to the clade that contained dinosaurs and herrerasaurs
    • If Saltopus elginensis is a herrerasaur, it helps present herrerasaurs have been in Europe within the Late Triassic and Saltopus can be the primary named herrerasaur from outdoors the Americas
    • As a result of they discovered herrerasaurs to not be dinosaurs (in 2017 within the new mannequin Herrerasauridae and Sauropodomorpha shaped Saurischia, the sister group to Ornithoscelida), they mentioned that Saurischia turned a paraphyletic group and proposed that “Saurischia ought to now be deserted as a clade title” and to solely embody Ornithoscelida (Ornithischia and Theropoda) and Sauropodomorpha as dinosaurs
    • Different animals that lived across the similar time and place as Saltopus embody Scleromochlus, a small archosauriform with lengthy legs; Brachyrhinodon, a lizard-like reptile; Stagonolepis, an armored reptile; Hyperodapedon , a beaked, lizard-like reptile; and Ornithosuchus and Erpetosuchus, pseudosuchians (crocodilian-line archosaurs)

    Enjoyable Truth:
    T. rex had massive highly effective tooth, however a number of fashionable animals have a lot larger tooth.

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