News thread

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New research on the timing of monotreme arrival in Australia. Also, meet Murrayglossus, a giant echidna.



www.theguardian.com/science/2022/mar/27/australian-scientists-solve-mystery-of-moment-monotremes-migrated

[creature386]

Voldemort's snake has been found in the Carboniferous: A fossil snake-like amniote that happens to have a similar genus name to a squamate owned by a noseless evil wizard has been described:
www.nature.com/articles/s41559-022-01698-y?fbclid=IwAR2E8VFJJ2JvV2Lv61jJ2qPPd9KJvx1Vjfx4oky4tudH0N-s6231dGX8uHE

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Evolution of life in cities (ecosystems in themselves).

www.inverse.com/science/city-animals-evolution

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Thescelosaurus leg from the Tanis site linked to the Chicxulub asteroid.

www.bbc.com/news/science-environment-61013740?xtor=AL-72-%5Bpartner%5D-%5Bbbc.news.twitter%5D-%5Bheadline%5D-%5Bnews%5D-%5Bbizdev%5D-%5Bisapi%5D

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Large bodies helped long-necked plesiosaurs overcome drag: phys.org/news/2022-04-large-bodies-extinct-marine-reptiles.html

Big (10 cm) Triassic ichthyosaur tooth suitable for snagging giant squid and small ichthyosaurs: www.theguardian.com/science/2022/apr/28/giant-ichthyosaurs-huge-tooth-points-to-sea-creatures-with-robust-bite?CMP=share_btn_tw

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Genomic study supports the idea that dingos are descended from wild dogs, not domestic ones.

www.newscientist.com/article/2317115-dingo-genome-suggests-australian-icon-not-descended-from-domestic-dogs/?utm_term=Autofeed&utm_campaign=echobox&utm_medium=social&utm_source=Twitter#Echobox=1651447764

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This turkey hunter found a ground sloth skull.

www.outdoorlife.com/hunting/hunter-finds-ground-sloth-skull/

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They found a new species of foot-long leech in New Jersey.

www.rutgers.edu/news/camden-research-team-names-new-species-leech-south-jersey-family

[Supercommunist]

Study suggest that while many dinosaurs were endotherms with many having higher metabolism than mammals, some dinosaurs like stegosaurids may have been ectotherms.

Although they had higher metabolic rates ancestrally, ornithischians reduced their metabolic abilities towards ectothermy. The physiological activities of such ectotherms were dependent on environmental and behavioural thermoregulation12, in contrast to the active lifestyles of endotherms.

www.nature.com/articles/s41586-022-04770-6


Full study is behind paywall but found a SD version of it.
www.sciencedaily.com/releases/2022/05/220525110846.htm

There are two big groups of dinosaurs, the saurischians and the ornithischians -- lizard hips and bird hips. The lizard-hipped dinosaurs, like Triceratops and Stegosaurus, had low metabolic rates comparable to those of cold-blooded modern animals. The bird-hipped dinosaurs, including theropods and the sauropods -- the two-legged, more bird-like predatory dinosaurs like Velociraptor and T. rex and the giant, long-necked herbivores like Brachiosaurus -- were warm- or even hot-blooded. The researchers were surprised to find that some of these dinosaurs weren't just warm-blooded -- they had metabolic rates comparable to modern birds, much higher than mammals.

Not sure I totally buy the idea of ceratopsians being full on ecthotherms, maybe the actual article meant mesotherms and the news media versions tried to simplify or misinterpreted things?

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Yeah, seems weird for ceratopsians and hadrosaurs to be ectotherms considering they were able to survive in Arctic areas that sometimes saw snow. I don't see how they could have survived there if they were full-blown ectotherms. If anything, sauropods seem to have preferred warmer habitats (although, this doesn't mean I think they were

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New possible record holder for the oldest tree in the world.

amp.theguardian.com/environment/2022/may/26/worlds-oldest-tree-cypress-chile

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[theropod]

May 26, 2022 5:57:05 GMT 5 Supercommunist said:

Study suggest that while many dinosaurs were endotherms with many having higher metabolism than mammals, some dinosaurs like stegosaurids may have been ectotherms.

Although they had higher metabolic rates ancestrally, ornithischians reduced their metabolic abilities towards ectothermy. The physiological activities of such ectotherms were dependent on environmental and behavioural thermoregulation12, in contrast to the active lifestyles of endotherms.

www.nature.com/articles/s41586-022-04770-6


Full study is behind paywall but found a SD version of it.
www.sciencedaily.com/releases/2022/05/220525110846.htm

There are two big groups of dinosaurs, the saurischians and the ornithischians -- lizard hips and bird hips. The lizard-hipped dinosaurs, like Triceratops and Stegosaurus, had low metabolic rates comparable to those of cold-blooded modern animals. The bird-hipped dinosaurs, including theropods and the sauropods -- the two-legged, more bird-like predatory dinosaurs like Velociraptor and T. rex and the giant, long-necked herbivores like Brachiosaurus -- were warm- or even hot-blooded. The researchers were surprised to find that some of these dinosaurs weren't just warm-blooded -- they had metabolic rates comparable to modern birds, much higher than mammals.

Not sure I totally buy the idea of ceratopsians being full on ecthotherms, maybe the actual article meant mesotherms and the news media versions tried to simplify or misinterpreted things?

They definitely use the term "ectotherms", but then, one rarely sees the therm mesotherm being used in technical context, and their definition of ectotherm is basically everything that plots below the 95% CI for endotherms (more on that below).

All in all, interesting study, but I do see some caveats:

Firstly, the sampling resolution is rather small. For each of the fossil ornithodiran taxa listed, only one specimen appears to have been analyzed. A total of 12, excluding birds. While the authors seem confident that complicating factors such as preservation would not significantly affect the results, it is hard to be sure of that with our limited knowledge of fossil biochemistry (even if that team is certainly among the foremost experts on the subject) and how it is impacted by fossilization under different conditions. Do the organic molecules they used as a basis to estimate metabolic rate really get preserved equally everywhere? This isn’t my area of expertise, but that appears a bit doubtful to me. I would be far more confident in the results if instead of one Stegosaurus and one Triceratops, they had analyzed 10 or 20, which showed consistency in the results.

Secondly, the use of the 95% CI as a predictor for endothermy seems odd as well. I think the appropriate interval for testing a hypothesis relating to the individual datapoints would have been the prediction interval, not the confidence interval, since we’re interested in the overall breadth of variation among organisms classed as endothermic, not just the confidence interval on the mean line. They also concede that their methodology underestimates metabolic rates (slightly), but it seems all they do to account for this is including organisms on the lower end of the 95% CI, such as the plesiosaur, as endotherms). I would be really interested in seeing the PIs for metabolic rates of ectotherms and endotherms here.

Thirdly, the results don’t seem to matchu up that well with those of osteohistology. The plesiosaur is a good example here, as they found a comparatively low metabolism, on the lower end of the 95% CI, while histology suggests a particularly high metabolic rate for derived sauropterygians (Fleischle et al. 2018).

Fourthly, some hadrosaurs and ceratopsians (whose representatives were found to be ectotherms by Wiemann at al.) lived in arctic environments. This might not necessarily contradict the results of the study directly (they do not state what taxon hadrosaur and ceratopsian they analyzed or from what locality they are, only that they are from Cretaceous, duh who would have thought), but it sure precludes generalizations. In the extant world, the only ectothermic amnioted north of the polar circle are a single lizard and a handful of lissamphibians. And unlike a small lizard or a frog, an adult Pachyrhinosaurus or Edmontosaurus would hardly have the ability to hibernate under a log to wait out the winter. Now granted, the Cretaceous was warmer than today, but still, even in temperate regions we see relatively few ectotherms, and those that we do see are all small and can seek out thermally buffered sites to spend the winter. There are reasons we don’t have giant monitor lizards or constrictor snakes, giant turtles (except the endothermic leatherback turtle, that is) or crocodiles in the temperate zone today. Admittedly they are also related to reproduction, but we do have various small species, so that’s not all of the story. Temperate ectotherms are size-limited, definitely to something far smaller than a large ceratopsid. Staying active during the polar winter would have been impossible for an ectotherm for obvious reasons, no sunlight equals no ability to reach activity temperatures, and sheltering and hibernating like extant temperate ectotherms seems hardly feasible. Here some more information on the taxa sampled as well as a larger sample size including polar dinosaurs would have been very nice.

Also, finally do note that this says nothing about gigantothermy/inertial homeothermy, but only true endothermy. So it’s entirely plausible that large hadrosaurs, Stegosaurs or Ceratopsians, if they weren’t endotherms, still maintained stable body temperatures by virtue of their large size.

That press coverage still isn’t very good though, seeing how it mixed up ornithischians and saurischians…


Fleischle, C.V., Wintrich, T. and Sander, P.M. 2018. Quantitative histological models suggest endothermy in plesiosaurs. PeerJ 6: e4955.

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Fourthly, some hadrosaurs and ceratopsians (whose representatives were found to be ectotherms by Wiemann at al.) lived in arctic environments. This might not necessarily contradict the results of the study directly (they do not state what taxon hadrosaur and ceratopsian they analyzed or from what locality they are, only that they are from Cretaceous, duh who would have thought), but it sure precludes generalizations. In the extant world, the only ectothermic amnioted north of the polar circle are a single lizard and a handful of lissamphibians. And unlike a small lizard or a frog, an adult Pachyrhinosaurus or Edmontosaurus would hardly have the ability to hibernate under a log to wait out the winter. Now granted, the Cretaceous was warmer than today, but still, even in temperate regions we see relatively few ectotherms, and those that we do see are all small and can seek out thermally buffered sites to spend the winter. There are reasons we don’t have giant monitor lizards or constrictor snakes, giant turtles (except the endothermic leatherback turtle, that is) or crocodiles in the temperate zone today. Admittedly they are also related to reproduction, but we do have various small species, so that’s not all of the story. Temperate ectotherms are size-limited, definitely to something far smaller than a large ceratopsid. Staying active during the polar winter would have been impossible for an ectotherm for obvious reasons, no sunlight equals no ability to reach activity temperatures, and sheltering and hibernating like extant temperate ectotherms seems hardly feasible. Here some more information on the taxa sampled as well as a larger sample size including polar dinosaurs would have been very nice.

To add to this these dinosaurs did not migrate either. There is literally no way around the fact that these hadrosaurs and ceratopsians had to endure dark winters and freezing temperatures annually throughout their entire lives.

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The first dinosaur unique to Nevada: Nevadadromeus.

www.reviewjournal.com/local/local-nevada/meet-nevadadromeus-the-first-dinosaur-unique-to-the-silver-state-2588510/