Episode 399: The numerous makes use of of melanin

Episode 399: The numerous makes use of of melanin. Maria McNamara teaches us about melanin, melanosomes, and what they’ll (and might’t) inform us about dinosaur colours.

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Maria McNamara, a paleobiologist and professor of paleontology on the College of Organic, Earth and Environmental Sciences at College Faculty Cork. Observe her on twitter @MariaMcN_palaeo and see extra particulars on Eire’s fossil heritage right here.



The dinosaur of the day: Dyoplosaurus

  • Ankylosaur that lived within the Late Cretaceous in what’s now Alberta, Canada (Dinosaur Park Formation)
  • Appeared like different ankylosaurs, with armor overlaying its physique, walked on all fours, had a tail membership
  • Estimated to be 13 to fifteen ft (3.9 to 4.5 m) lengthy and weigh 3300 to 5500 lb (1500 to 2500 kg)
  • Comparatively small, with an extended, slender tail membership
  • Tail membership had ten vertebrae that shaped the deal with and a number of other osteoderms that shaped the knob
  • Tail membership knob was longer than it was vast
  • In all probability wasn’t born with the tail membership, and shaped it later in life (attainable that the tail membership present in Dyoplosaurus was nonetheless rising)
  • In 2009, Victoria Arbour did a examine (CT scans of golf equipment referred to Dyoplosaurus and Euoplocephalus) on the affect pressure of ankylosaur tail membership strikes and located Dyoplosaurus couldn’t generate sufficient pressure to puncture bone (knob was too small)
  • Could imply the knobs weren’t primarily for protection. Could have been used additionally for show
  • Had slender, bladelike neural spines
  • Had triangular osteoderms on the edges of the entrance of the tail
  • Sacral fenestrae (holes within the pelvis) shaped a butterfly-like association
  • Herbivorous
  • Kind species is Dyoplosaurus acutosquameus
  • Described by William Parks in 1924
  • Genus identify means “double armored lizard”
  • Species identify means “sharp scale”
  • Intently associated to Scolosaurus and Anodontosaurus
  • Holotype present in 1919 by Levi Sternberg, close to Crimson Deer River
  • Holotype features a partial cranium roof, jaw fragments with tooth, osteoderms, pores and skin impressions, vertebrae, tail membership, decrease leg bones, ribs
  • Holotype was principally the again half of the dinosaur, with the entrance half principally lacking
  • Holotype was in all probability an virtually absolutely mature particular person
  • Holotype cranium was initially comprised of a number of scattered fragments, however a variety of the fragments had been discarded in 1924 as a result of they might not be articulated (the remainder made up an incomplete entrance of the cranium roof)
  • Parks wrote, the tail membership was “distinctly completely different from any beforehand described and, so far as I’m conscious, from any which have been collected.”
  • Three tooth had been preserved with the fragments, however Parks solely illustrated the one he thought-about the most effective in his description
  • Tooth has since been misplaced, although the opposite two tooth are nonetheless round
  • Gilmore in 1930 referred a cranium to Dyoplosaurus, based mostly on similarities within the tooth and having osteoderms on the cranium, however he stated the cranium seemed so much like Euoplocephalus tutus
  • Gilmore additionally stated Parks’ illustration of the Dyoplosaurus tooth in 1924 was inaccurate (tooth seemed extra nodosaurid than ankylosaurid) and proposed corrections, together with his personal illustrations of the tooth
  • Two specimens referred to Dyoplosaurus have partial tail golf equipment
  • Evgeny Maleev named a second species in 1956: Dyoplosaurus giganteus, based mostly on a big specimen with caudal vertebrae, foot bones, and osteoderms together with a partial tail membership knob
  • Fossils present in Mongolia (Nemegt Formation)
  • Maleev stated it had comparable vertebrae to Dyoplosaurus acutosquameus however was completely different as a result of it was greater
  • In 1977 it was reassigned to Tarchia by Tumanova, as Tarchia gigantea
  • In 2014, Victoria Arbour and others discovered the holotype to not have diagnostic options (had options in widespread with all ankylosaurines), and regarded it to be a nomen dubium
  • Additionally stated the variations in measurement might be from particular person variation or ontogeny
  • Walter Coombs synonymized Dyoplosaurus, Scolosaurus, and Anodontosaurus with Euoplocephalus in 1971 (one of many Dyoplosaurus jaws was the identical as different Euoplocephalus specimens)
  • Coombs, when synonymizing, stated the variability in ankylosaur skulls from Dinosaur Park Formation and Horseshoe Canyon Formation meant both every specimen was its personal species or there was just one species of ankylosaur, and he determined there was just one species
  • Then in 2009, Victoria Arbour and others redescribed Dyoplosaurus and located it to be legitimate (hips, vertebrae, and particularly the tail is completely different sufficient), and urged the synonymy was due to the fragmentary nature of the specimens of Euoplocephalus
  • Wrote, “it may be essential to look past conventional cranial characters with a purpose to precisely appraise the quantity and nature of assorted ankylosaurid taxa”
  • Arbour and others proposed the variation in skulls meant there have been a number of kinds of ankylosaurs
  • Euoplocephalus was additionally present in a youthful formation (Horseshoe Canyon Formation), a pair million years youthful than the formation the place Dyoplosaurus was discovered (Dinosaur Park Formation)
  • In 2011, Thomson and others confirmed Dyoplosaurus was legitimate
  • In 2011, Tetsuto Miyashita and others seemed on the skulls of Euoplocephalus, and talked about that there are not any cranium characters that separate Dyoplosaurus from Euoplocephalus (options that make them distinctive are within the pelvis and toes), so it’s attainable some skulls referred to Euoplocephalus could also be Dyoplosaurus
  • Lived in an space with frequent flooding
  • Different dinosaurs that lived across the identical time and place embrace the ankylosaurs Edmontonia, Euoplocephalus, and Scolosaurus, the ceratopsid Chasmosaurus, hadrosaurs Corythosaurus, Gryposaurus, and Parasaurolophus, the tyrannosaur Gorgosaurus, the dromaeosaur Hesperonychus, the troodontid Latenivenatrix, and the caenagnathids Caenagnathus and Chirostenotes

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