Synchrotron-based imaging techniques of a 50 million-year-old lizard skin have identified the presence of teeth which are invisible to visible light, demonstrating for the first time that this fossil animal was more than just a skin moult. 

Researchers used Synchrotron Rapid Screening X-ray Fluorescence at the Stanford Synchrotron Radiation Lightsource in California to map the chemical make up of a rare fossil lizard skin - powerful x-rays enabled the team to map the presence of phosphorus from teeth in this ancient reptile.

The process involved in the formation of sperm cells involves symmetry, the equal chance that a mammalian egg will be fertilized by "male" sperm, carrying a Y chromosome or a "female" sperm, carrying an X chromosome, and that symmetry means that roughly the same number of males and females are born, which is necessary for the long-term survival of a species.

A study in BMJ's Christmas issue, which spares no effort in its annual attempt to see who in science media rewrites press releases without even reading them, has determined why Rudolph, the famous extra reindeer of Santa we will not show here due to little desire to pay royalties, has a red nose.

Rudolph's nose is red because it is richly supplied with red blood cells which help to protect it from freezing and to regulate brain temperature. This superior "nasal microcirculation" is essential for pulling Santa Claus's sleigh under extreme temperatures, says the BMJ study.

A future without fossil fuels is ideal but impractical in the short term. 

However, for people not afraid of science, a PNAS paper showing that synthetic biology can be used to manipulate hydrocarbon chemicals, found in soaps and shampoos, in cells is some welcome news. This could mean fuel for cars or household power created from naturally-occurring fatty acids. Fossil fuels even more organic than current fossil fuels. Delightful!

The parasite Toxoplasma gondii (T. gondii) is one of the major causes of food-borne diseases but new insights into how the immune system combats T. gondii could lead to the development of long-sought vaccines. 

To fight off pathogens, the immune system relies on Toll-like receptors (TLRs), a class of proteins that recognize microbes and activate immune responses. The important role of TLR11 in recognizing the T. gondii infection was previously demonstrated by a team led by Sankar Ghosh of Columbia University and Alan Sher of the National Institute of Allergy and Infectious Diseases. But scientists had not yet identified any TLRs, including TLR11, that could promote survival in infected animals. 

A new paper detailing research from the rainforests of Panama provides an unprecedented level of detail regarding the diversity and distribution of arthropod species from the soil to the forest canopy - the authors estimate that a 6,000 hectare forest hosts a total of around 25,000 arthropod species, a figure vastly outnumbering that of better-studied organisms.