Chelicerata - Encyclopedia.com
Jun 27, 2018 · Chelicerata. Chelicerata (phylum Arthropoda) A subphylum of arthropods in which the body comprises a cephalothorax or prosoma and an abdomen or opisthosoma, the first pair of feeding structures are the chelicerae that give the subphylum its name, and there are no antennae. The chelicerates are known as fossils from the early Palaeozoic, and ...
Sea Spiders - Encyclopedia.com
May 18, 2018 · Sea spiders (phylum Arthropoda, class Pycnogonida) are a group of arthropods that take their common name from their superficial resemblance to the true spiders. Although rarely seen, these are widespread animals occurring in every ocean, with a preference for cooler waters. Sea spiders occupy a wide range of habitats: some species have been ...
Merostomata (Horseshoe Crabs) - Encyclopedia.com
Class Chelicerata. Subclass Merostomata. Number of families 1. Thumbnail description Marine creatures distinguished by a large, hard exoskeleton that includes an arched, horseshoe-shaped shield in front (prosoma), a middle portion (opisthosoma), and a thin tail (telson); they are among the oldest living organisms
Telson - Encyclopedia.com
May 8, 2018 · telson. telson The spike-like, terminal segment of the opisthosoma that occurs in certain chelicerates (Chelicerata), e.g. limulids and eurypterids. The prominent, backward-pointing spine at or near the rear extremity of a trilobite (Trilobita) is also called a telson, although it may or may not be the equivalent of a true telson.
Arthropoda - Encyclopedia.com
May 23, 2018 · Arthropods are divided into four subphyla. These are the Chelicerata, the Crustacea, the Uniramia, and the Trilobita. The last consists exclusively of extinct forms. Subphylum Chelicerata. The chelicerates include the horseshoe crabs, scorpions, spiders, ticks, mites, sea spiders, and other related species. They are characterized by the ...
Cephalothorax - Encyclopedia.com
May 29, 2018 · cephalothorax In some members of the phylum Arthropoda, the fused head and thorax. It is found in members of the Chelicerata (classes Merostomata, Arachnida, and Pycnogonida), and in most Crustacea. In spiders, it is the prosoma, which is covered by a sclerotized plate (carapace), and which bears the walking limbs, pedipalps, chelicerae, and eyes.
Arachnida (Spiders, Scorpions, Mites, and Ticks)
Arachnida. (Spiders, scorpions, mites, and ticks) Phylum Arthropida. Class Chelicerata. Subclass Arachnida. Number of families 648. Thumbnail description. Highly recognizable and populous eight-legged invertebrates with two body parts (a prosoma and an abdomen), pedipalps, book lungs or tracheae, sometimes poisonous fangs, and generally the ...
Arachnids - Encyclopedia.com
Jun 8, 2018 · Arachnids are members of the subphylum Chelicerata, which also includes the phylogenetically-related (related by evolution) ancient horseshoe crabs. Like other arthropods, arachnids have paired, jointed appendages, a hardened exoskeleton, segmented body, and well developed head.
Araneae - Encyclopedia.com
Araneae (spiders; subphylum Chelicerata, class Arachnida) Very large and diverse order of predatory arachnids most of which feed on arthropods, although the large tarantulas (Mygalomorphs) will catch nestling birds and other vertebrates, and some will catch tadpoles and small fish. The prosoma has a uniform dorsal carapace bearing two–eight ...
Horseshoe Crabs - Encyclopedia.com
Merostomata. Merostomata (phylum Arthropoda) Class which includes the king crabs (horse-shoe crabs) and the extinct eurypterids or ‘water scorpions’. Eurypterids were usually 10–20 cm in length, but some were much larger, e.g. Pterygotus which grew up to 2 m long. They ranged from the Ordovician to the end of the Palaeozoic.