Post has attachment
Photo
Edmontonia rugosidens’s most distinguishing characteristic may be its back, which served as armor for the dinosaur. Bony plates called osteoderms covered this animal from the Late Cretaceous (about 100 to 66 million years ago). The osteoderms weren’t bound together, which allowed a certain flexibility and helped prevent puncture wounds from predators. Spikes along the dinosaurs’ sides added protection. Edmontonia is classified as a nodosaurid ankylosaur, and lacks the weapon-like club tail that relatives such as Ankylosaurus had. Instead, Edmontonia’s tails featured a row of triangular spikes that were perhaps used to slash aggressors. A keen sense of smell also aided these herbivores, helping them both avoid predators and find food. Edmontonia roamed Canada as well as other parts of North America and is in fact named for Edmonton, the capital of Alberta, where it was first discovered.

Read more about Edmontonia and other dinosaurs: https://goo.gl/RmHwE6

Post has attachment
In anticipation of the August 21 eclipse, take a quick look at some notable buildings dedicated to exploring the cosmos: observatories and planetariums around the country. From our very own Hayden Planetarium in the Rose Center for Earth and Space to Chicago’s Art Deco Adler Planetarium, L.A.’s beloved Griffith Observatory, and Hawaii’s gleaming Mauna Kea Observatory sitting 13, 796 feet above sea level, Curbed has compiled a list of the top 10 U.S. observatories and planetariums.

Post has attachment
Home Sweet Home
I've written a new Parasite of the Day blog post! This one is about parasitic snail that lives on sea urchins and feed on their spines. But they do more than just that - they also alter their host's spines in such a way to make the spine a more suitable home for them to raise their brood. To read more about this rather tricky mollusc, follow the link below

Post has attachment
A total solar eclipse is a singularly magnificent phenomenon. The Great American Eclipse on August 21, 2017, will be visible as either a partial or a total eclipse throughout North America. See how it appears from various vantage points on Earth, and watch from space as the shadow sweeps across the continent.

Learn more on the blog: https://goo.gl/JHR6yr

Post has attachment
Photo
These arachnids make dinner out of their potential predators in a startling role reversal
At less than a tenth of an ounce, the regal jumping spider can prey on frogs and lizards two to three times its own weight, according to a new study in the Journal of Arachnology.

It's the first time scientists have published observations of jumping spiders—the biggest family of spiders—eating vertebrates.

Source & further reading:
http://news.nationalgeographic.com/2017/08/jumping-spiders-lizards-frogs-predators/

Journal article:
http://americanarachnology.org/JoA_free/JoA_v45_n2/arac-45-2-238.pdf

Photograph by Martin Fisher

#biodiversity #spiders #coolcritters #science

Post has attachment
FROM THE ARCHIVES: in anticipation of Monday's eclipse, the Museum is releasing this rarely seen footage of a 1937 Museum expedition to the Peruvian Andes to capture some of the first color video of a total solar eclipse. The trip included shots taken from a plane at 25,000 feet at the moment of totality--images which would improve scientists' understanding of the Sun's corona.
Watch an excerpt from “The Peruvian Eclipse Expedition,” below, filmed during the Hayden Planetarium-Grace Peruvian Eclipse Expedition of 1937. And learn more about the crew and their instruments on the blog: https://goo.gl/MSsZVq

Post has attachment
There is a cool new homing pigeon result out in JEB that suggests that the pigeons travel at lower speeds and have different wingbeat characteristics when their routes are less familiar. The authors seem to be pitching a cognitive explanation, but I think there might be a simpler mechanism at play...

All mobile agents (animals and robots, walking or flying) have physical limitations that require slowing down in order to sustain tight turns. If you find yourself in a tortuous path with lots of turns, speeds will often get stuck far away from top speed because there are not enough straight-aways to accelerate to top speed before having to slow for another turn. In this case of homing pigeons, their lack of route familiarity can lead to tortuous paths with lots of turns. So couldn't that be enough to explain the differences in airspeed and wingbeat characteristics? In other words, they don't have to be choosing to fly more slowly to improve route learning. The slowdown could be due to biomechanical constraints on flight that prevent flying at top airspeed for all but the straightest (and thus most familiar) routes.

Primary source:

"Homing pigeons (Columba livia) modulate wingbeat characteristics as a function of route familiarity"
by Lucy Taylor, Steven Portugal, and Dora Biro
Journal of Experimental Biology (2017), 220:2908–2915
http://doi.org/10.1242/jeb.154039

Abstract
=====
Mechanisms of avian navigation have received considerable attention, but whether different navigational strategies are accompanied by different flight characteristics is unknown. Managing energy expenditure is critical for survival; therefore, understanding how flight characteristics, and hence energy allocation, potentially change with birds' familiarity with a navigational task could provide key insights into the costs of orientation. We addressed this question by examining changes in the wingbeat characteristics and airspeed of homing pigeons (Columba livia) as they learned a homing task. Twenty-one pigeons were released 20 times individually either 3.85 or 7.06 km from home. Birds were equipped with 5 Hz GPS trackers and 200 Hz tri-axial accelerometers. We found that, as the birds' route efficiency increased during the first six releases, their median peak-to-peak dorsal body (DB) acceleration and median DB amplitude also increased. This, in turn, led to higher airspeeds, suggesting that birds fly slower when traversing unfamiliar terrain. By contrast, after route efficiency stabilised, birds exhibited increasing wingbeat frequencies, which did not result in further increases in speed. Overall, higher wind support was also associated with lower wingbeat frequencies and increased DB amplitude. Our study suggests that the cost of early flights from an unfamiliar location may be higher than subsequent flights because of both inefficient routes (increased distance) and lower airspeeds (increased time). Furthermore, the results indicate, for the first time, that birds modulate their wingbeat characteristics as a function of navigational knowledge, and suggest that flight characteristics may be used as ‘signatures’ of birds' route familiarity.
=====

Post has attachment
A nice confirmation of theory! The adult and juvenile stages of frogs have been decoupled so that frogs and tadpoles effectively evolve independently from each other. It's like two organisms evolving at once that just happen to be packaged in the same genome.

Abstract snippet: "Antagonistic selection is expected to drive low genetic correlations between life stages, theoretically permitting stages to evolve independently. Here we describe, using Australian frog radiation, the evolutionary consequences on morphological evolution when life stages are under different selective pressures. ... Australian frogs and their tadpoles are evolving independently; their markedly different morphospaces and contrasting estimated evolutionary histories of body shape diversification indicate that different processes are driving morphological diversification at each stage."

Full bib info and abstract:

"Adult frogs and tadpoles have different macroevolutionary patterns across the Australian continent"
by Emma Sherratt, Marta Vidal-García, […]J. Scott Keogh
Nature Ecology & Evolution (2017)
http://doi.org/10.1038/s41559-017-0268-6

Abstract
=====
Developmental changes through an animal’s life are generally understood to contribute to the resulting adult morphology. Possible exceptions are species with complex life cycles, where individuals pass through distinct ecological and morphological life stages during their ontogeny, ending with metamorphosis to the adult form. Antagonistic selection is expected to drive low genetic correlations between life stages, theoretically permitting stages to evolve independently. Here we describe, using Australian frog radiation, the evolutionary consequences on morphological evolution when life stages are under different selective pressures. We use morphometrics to characterize body shape of tadpoles and adults across 166 species of frog and investigate similarities in the two resulting morphological spaces (morphospaces) to test for concerted evolution across metamorphosis in trait variation during speciation. A clear pattern emerges: Australian frogs and their tadpoles are evolving independently; their markedly different morphospaces and contrasting estimated evolutionary histories of body shape diversification indicate that different processes are driving morphological diversification at each stage. Tadpole morphospace is characterized by rampant homoplasy, convergent evolution and high lineage density. By contrast, the adult morphospace shows greater phylogenetic signal, low lineage density and divergent evolution between the main clades. Our results provide insight into the macroevolutionary consequences of a biphasic life cycle.
=====

Post has attachment
+Bill Sullivan and +Kate Stone had an article about ScienceConnected, the parent of the GotScience.org webzine, published today in Plos. It describes why making science more accessible is important.


http://blogs.plos.org/scicomm/2017/08/14/science-connected-accessible-science-communication/
Wait while more posts are being loaded