A neat paper in Nature Science Reports an open paper with nice illustrations
A new tyrannosaur with evidence for anagenesis and crocodile-like facial sensory system
Thomas D. Carr1, David J. Varricchio2, Jayc C. Sedlmayr3, Eric M. Roberts4 & Jason R. Moore5
1Carthage College, 2001 Alford Park Drive, Kenosha, WI 53140, USA. 2Department of Earth Sciences, Montana State University, P.O. Box 173480, Bozeman, MT 59717-3480, USA. 3Louisiana State University Health Sciences Centre - School of Medicine, 1901 Perdido Street, New Orleans, LA 70112, USA. 4Geosciences, College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia. 5Honors College, University of New Mexico, Albuquerque, NM 87131, USA.
A new species of tyrannosaurid from the upper Two Medicine Formation of Montana supports the presence of a Laramidian anagenetic (ancestor-descendant) lineage of Late Cretaceous tyrannosaurids. In concert with other anagenetic lineages of dinosaurs from the same time and place, this suggests that anagenesis could have been a widespread mechanism generating species diversity amongst dinosaurs, and perhaps beyond. We studied the excellent fossil record of the tyrannosaurid to test that hypothesis. Phylogenetic analysis places this new taxon as the sister species to Daspletosaurus torosus. However, given their close phylogenetic relationship, geographic proximity, and temporal succession, where D. torosus (~76.7–75.2 Ma) precedes the younger new species (~75.1–74.4 Ma), we argue that the two forms most likely represent a single anagenetic lineage. Daspletosaurus was an important apex predator in the late Campanian dinosaur faunas of Laramidia; its absence from later units indicates it was extinct before Tyrannosaurus rex dispersed into Laramidia from Asia. In addition to its evolutionary implications, the texture of the facial bones of the new taxon, and other derived tyrannosauroids, indicates a scaly integument with high tactile sensitivity. Most significantly, the lower jaw shows evidence for neurovasculature that is also seen in birds.
Jane Zhang sing's the soprano's song from the movie The Fifth Element. When originally recorded it was heavily sampled and edited as it was written to be impossible to sing, The story is the song writer didn't know about the range and flexibility some singers have. She uses a microphone, but still....
Enhancement of human color vision by breaking the binocular redundancy
Bradley S. Gundlach, Alireza Shahsafi, Gregory Vershbow, Chenghao Wan, Jad Salman, Bas Rokers, Laurent Lessard, Mikhail A. Kats
To see color, the human visual system combines the responses of three types of cone cells in the retina - a process that discards a significant amount of spectral information. We present an approach that can enhance human color vision by breaking the inherent redundancy in binocular vision, providing different spectral content to each eye. Using a psychophysical color model and thin-film optimization, we designed a wearable passive multispectral device that uses two distinct transmission filters, one for each eye, to enhance the user's ability to perceive spectral information. We fabricated and tested a design that "splits" the response of the short-wavelength cone of individuals with typical trichromatic vision, effectively simulating the presence of four distinct cone types between the two eyes ("tetrachromacy"). Users of this device were able to differentiate metamers (distinct spectra that resolve to the same perceived color in typical observers) without apparent adverse effects to vision. The increase in the number of effective cones from the typical three reduces the number of possible metamers that can be encountered, enhancing the ability to discriminate objects based on their emission, reflection, or transmission spectra. This technique represents a significant enhancement of the spectral perception of typical humans, and may have applications ranging from camouflage detection and anti-counterfeiting to art and data visualization.