Episode 412: Extinction Extravaganza. Evidence of extinctions from volcanic rock, in craters, and even on the moon. Plus a new abelisaurid from Patagonia.

News:

• A new abelisaurid from Patagonia, Elemgasem, was small but named after a mighty Tehuelche god source
• Scientists suggested volcanic eruptions could be the main reason for mass extinctions source
• Scientists suggested dinosaurs were on the decline before they went extinct source
• The moon includes evidence of asteroid impacts on Earth source
• There is a second underwater crater that is from around the same time as Chicxulub source
• A new model shows the tsunami after the Chicxulub impact source
• The Chicxulub impact may have triggered an earthquake that lasted weeks to months source
• Precipitation played a role in the abundance and success of hadrosaurs and ceratopsians in the Late Cretaceous in what is now Alaska source
• Dinosaurs may have been successful and diverse because of the differences in their diets source
• 80 million year old dinosaur eggs were recently found in Jiangxi Province, China source
• In Skåne, Sweden, large carnivorous dinosaurs from the Late Triassic were recently found source
• Reykjavík might be getting a Triceratops skeleton to display source
• To celebrate National Fossil Day, Mississippi State University’s Dunn-Seiler Museum had a competition to name their Triceratops source
• A man in New Zealand used VR to sculpt and then 3D print a life-sized model of a Tyrannosaurus source

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The dinosaur of the day: Brachytrachelopan

• Dicraeosaurid sauropod that lived in the Late Jurassic in what is now Chubut Province, Argentina (Cañadón Calcáreo Formation)
• Similar in shape to other sauropods, walked on all fours, had a long tail, but had a short neck
• Estimated to be less than 33 ft (10 m) long
• Had a short neck, about 40% shorter than other dicraeosaurids (which are diplodocoids) and shorter than any known sauropod
• Dicraeosaurids are known for their shorter necks
• Short necks may have helped with low browsing
• Probably ate plants that grew to about 3 to 6.5 ft (1 to 2 m) tall
• Might have filled the same niche as large iguanodontians, which weren’t around in the Late Jurassic in Gondwana, but there were many large iguanodontians during that time in what is now North America (where there were no dicraeosaurids)
• Helps show that dicraeosaurids had a rapid radiation and really spread out in the Late Jurassic in the Southern Hemisphere, after Gondwana separated from the northern continents (in the Middle Jurassic)
• Named in 2005 by Oliver Rauhut and others
• Type species is Brachytrachelopan mesai
• Species name is in honor of Daniel Mesa, a local shepherd who found the dinosaur while looking for stray sheep
• Genus name means “short-necked Pan” and refers to Pan, the god of the shepherds
• Fossils were found articulated
• Holotype includes vertebrae, including 8 neck vertebrae, part of the ribs, part of the lower left leg and part of the hip
• Probably had 12 neck vertebrae, like other dicraeosaurids
• Lots of the fossils were probably eroded away before it was discovered
• In a study published last month, Guillermo Windholz and others did histology on Brachytrachelopan and found the holotype was not fully grown yet, and though it was large it was also not yet sexually mature
• Found the holotype specimen was at least four years old when it died
• Other dinosaurs that lived around the same time and place included abelisaurids, stegosaurs, and other sauropods like Tehuelchesaurus
• Other animals that lived around the same time and place included crocodylomorphs and fish

Fun Fact:

The Pacific Ocean is shrinking and that may give rise to “Amasia”, Earth’s next supercontinent

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