Thylacocephala
Автор:
Jesse Russell,Ronald Cohn, 107 стр., издатель:
"Книга по Требованию", ISBN:
978-5-5084-5723-5
High Quality Content by WIKIPEDIA articles! The Thylacocephala (from the Greek ??????? or thylakos, meaning "pouch", and ?????? or cephalon meaning "head") are a unique group of extinct arthropods, with possible crustacean affinities. As a class they have a short research history, having been erected in the early 1980s. They typically possess a large, laterally flattened carapace that encompasses the entire body. The compound eyes tend to be large and bulbous, and occupy a frontal notch on the carapace. They possess three pairs of large raptorial limbs, and the abdomen bears a battery of small swimming limbs. The earliest thylacocephalan fossil is thought to date from the lower Cambrian, while the class has a definite presence in Lower Silurian marine communities. As a group, the Thylacocephala survived to the Upper Cretaceous. Beyond this, there remains much uncertainty concerning fundamental aspects of the thylacocephalan anatomy, mode of life, and relationship to the Crustacea,...