Friday, 2 September 2016

Favourite figures from papers 2

Due to the popularity of the last post with over 1000 people viewing the post, I thought it was worth doing a second. The first two were pointed out to me by comments on the last blog post, and are compliments of a tumblr that showed them, although sadly that tumblr seems to have gone inactive after 2 months. Please keep suggesting other figures that are worth being more widely seen

1. Dinosaur pain thresholds
McCrea et al., 2015. Vertebrate Ichnopathology: Pathologies Inferred from Dinosaur Tracks and Trackways from the Mesozoic. Ichnos 22, 235-260.
A set of tracks were discovered showing several deformities of the toes in theropods, including loss of the second digit on the foot. The authors showed a sense of humour by adding a speculative dinosaur pain scale  to the various toe deformities. Using what metric? Who really cares. If it is that brilliant there is nothing to not love.

2. Phytosaurs were not sniffing each like dogs
Senter 2002. Lack of pheromonal sense in phytosaurs and other archosaurs, and its implications for reproductive communication. Paleobiology 28, 544-550.
This weird group of animals look superficially like crocodiles (but are only somewhat closely related), but instead of having their nostrils at the front of the skull like in modern crocodiles, their nostrils are near their eyes. This has implications for their ability to use scent like other animals to detect reproductive pheromones by either sniffing the ground or cloacae (the shared urogenital opening found in most non-mammal terrestrial groups) without breaking their necks or getting their noses/heads squished as beautifully indicated by the figure.

3. The fighting dinosaurs
Figure 1 from Carpenter 1998. Evidence of predatory behavior by carnivorous dinosaurs. Gaia .
Found in 1971 and first described in 1974 by Barsbold (I couldn't find the paper to get the original figures) during the Soviet-Mongolian expeditions it remains one of the most famous fossils ever discovered. It preserves a Velociraptor and Protoceratops forever locked in combat, with the Protoceratops biting down on the right forearm of the Velociraptor, whilst the Velociraptor is kicking its famous sickle claw into the throat region of the Protoceratops. The Velociraptor probably killed the Protoceratops with this kick, but was trapped when its right leg ended up under the Protoceratops. The death scene may have been scavenged explaining the loss of the front limbs of the Protoceratops before ultimately being buried under a sand dune and fossilised. I was lucky enough to see the specimen in Mongolia and it truly is amazing, although having been transported around the world a lot in the last 40 years it is now particularly fragile and hidden in a basement, not the place for a Mongolian national treasure. Hopefully the new dinosaur museum being built in Ulanbataar will put it back on display.

4. Big mamma
Figure 1 from Norell et al., 1995. A nesting dinosaur. Nature 378, 774-776. 
Big mamma is a beautiful skeleton of an oviraptor (Citipati) sitting on its nest brooding its eggs. Oviraptors got their name "egg theives" when Roy Chapman Andrews first found them close to eggs and assumed they were stealing them from Protoceratops. Turns out it was an incredible misnomer and these dinosaurs (with their feathered bodies) brooded their eggs just like modern birds do. There is another specimen (Big Auntie) preserved in the same position as well.

5. T. rex described
Figure 1 from Oxborn 1905. Tyrannosaurus and other Cretaceous carnivorous dinosaurs. Bulletin of the AMNH 21, 259-265.
Possibly the most famous of all dinosaurs, and shamefully/shamelessly one of my favourites. What's not to love from its massive head to its tiny arms. The figured reconstruction shows it tail dragging but we know now that it held its tail out behind it in a far more active posture (see the last blog of favourite figures showing the transition from the Crystal Palace dinosaur reconstructions to the Deinonychus reconstruction by Bakker). It's also sad we no longer have skeletal humans for scale next to our dinosaur reconstructions.

6. The claw...
Figure 4 from Altangerel et al., 1993. Flightless bird from the Cretaceous of Mongolia. Nature 362, 623-626.
T. rex always gets a lot of abuse for its tiny arms, but it doesn't have the smallest or most reduced arms of the dinosaurs. This ridiculously tiny arm belongs to Mononykus (one claw), an alverezsaur which has reduced its arm to basically nothing with one finger. The morphology has been suggested to be linked to breaking into termite mounds although whether it could has not been tested.

7. Pterosaur meets cat
Figure 6 from Martin-Silverstone et al., 2016. A small azhdarchoid pterosaur from the latest Cretaceous, the age of flying giants. Royal Society Open Science.
In the Cretaceous most known pterosaurs (the flying reptiles) are huge creatures, with species like Quetzalcoatlus reaching giraffe sizes. The paper describes a new species of pterosaur from the late Cretaceous of Canada which shows itself to be nearing maximum size, but yet is still small. Mark Witton (an author and very accomplished palaeo-artist) shows its size relative to a cat, and for me (and the internet as a whole) that is a winning combination. Check out the paper as it is open access too!

8. How do you make a chicken walk like a dinosaur?
Figure 1 from Grossi et al., 2014. Walking like dinosaurs: Chickens with artificial tails provide clues about non-avian theropod locomotion. PLoS One 9, e88458.
In response to the question of how do you make a chicken walk like a dinosaur, you stick a plunger on its butt. Well, not exactly a plunger, but a weight that resembles a plunger. As your chicken grows you increase the weight and the result is a more upright posture in their legs relative to the control and the control weight groups. Whilst there are issues with the assumptions as a whole, mostly due to a lot of the muscles that control the leg movements in dinosaurs attach in the tail which isn't the case in birds (as they don't have a long tail), it is an interesting experiment and result.

9. The upside down hallucination inducing animal
Figure 2 from Conway-Morris 1977. A new metazoan from the Cambrian Burgess Shale of British Columbia. Palaeontology 20, 623-640.
Hallucigenia is a weird and wonderful creature from the spectacular Lagerst├Ątten (site of exceptional fossil preservation) of the Burgess Shale. When first found there was much debate over which way round the animal goes, and Conway-Morris speculated it went spikes down. Funnily he even went as far as to speculate about the hypothetical arrangement of muscles (parts B and C of the figure) that would allow the animals to walk on the spines. Recent papers suggest that he got it upside down, and it walked on the soft legs, and had spines on its back to protect itself.

10. Lucy in the sky with broken bones
Figure 2 from Kappelman et al., 2016. Perimortem fractures in Lucy suggest mortality from fall out of tall tree. Nature
Lucy is perhaps the most famous of the fossil hominins due to the remarkably well preserved skeleton (as far as hominins go). New research out suggests that this famous Australopithecus has a bunch of fractures similar to those found in modern humans falling from height and have linked the fossil breaks to Lucy falling out of a tree. Based on the news reports, this is highly controversial and it will be interesting to see whether this hypothesis withstands the test of time.
This one also comes with a bonus video:

That rounds off this next set of 10 favourite figures, across the spectrum from of categories from funny pictures to interesting science. Please let me know yours as I quite enjoy doing these posts!

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