{'fraction_non_alphanumeric': 0.025806451612903226, 'fraction_numerical': 0.01129032258064516, 'mean_word_length': 5.402061855670103, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Embryos Provide Clues to Early Animal Evolution

Fossil-hunters may not be able to contribute much to understanding the evolution of various animal body plans—the architectures that distinguish, say, a mollusk from an arthropod. That was the message for paleontologists at this year's Geological Society of America meeting in New Orleans, where developmental biologists, including the authors of an Article in this week's issue (p.1319), explained that the key innovations probably took place in soft, larvalike creatures more than 600 million years ago—long before the first sizable animal fossils appear in the record.