Scientists have found the oldest sample of animal sperm, concealed in a 100 million-year-old piece of amber. Paleontologists discovered the sample in the reproductive tract of an ancient female crustacean encased in resin -- one of several samples of ostracods from Myanmar. The previously unknown species of crustacean, now named Myanmarcypris hui, resembles a modern day mussel and is an example of an ostracod. Ostracods are small animals that date back some 500 million years, and can still be found in oceans, freshwater lakes and rivers. Using 3D X-ray reconstructive technology, scientists analyzed several ostracod specimens, studying their limbs and...