BI256 Lecture 17: Anthropoda 2 - Chelicerates and Myriapods
Document Summary
Feb 13th arthropoda 2 lecture 17 bi256 animals. Chelicerates are known from over 445 million years ago. Have two body regions (tagmata): the cephalothorax and the abdomen. Generally have six pairs of cephalothoracic appendages including chelicerae, pedipalps, and 4 pairs of legs. Lack mandibles, have no antennae; most species suck liquid food from prey. Class pycnogonida: sea spiders: all have small, thin bodies with leg span up to 0. 75m in length, approx. 1000 species in marine habitats ranging from shallow to deep ocean basins: some species duplicate somites, and may have five or six pairs of legs. Contains extinct eurypterids and living fossils called xiphosurids (horseshow crabs) (5 extant species) Unsegmented shield or carapace covers body in front of a broad abdomen and a long telson (tail) Cephalothorax has 5 pairs of walking legs (includes pedipalps) and a pair of chelicerae book gills. Class arachnida have a great anatomical diversity: more than 80,000 species.
