A ricinuleid, commonly known as a "hooded tickspider", is an invertebrate animal belonging to the order Ricinulei in the class Arachnida, in the subphylum Chelicerata of the phylum Arthropoda. Orders Acarina Amblypygi Araneae Opiliones Palpigradi Pseudoscorpionida Ricinulei Schizomida Scorpiones Solifugae Uropygi The arachnids, Arachnida, are a class of invertebrate animals in the subphylum Chelicerata. ... Classes Arachnida - spiders, scorpions, etc. ... Phylum (plural: phyla) is a taxon used in the classification of animals, adopted from the Greek phylai the clan-based voting groups in Greek city-states. ... Subphyla and Classes Subphylum Trilobitomorpha Trilobita - Trilobites (extinct) Subphylum Chelicerata Arachnida - Spiders, Scorpions, etc. ...

Physical description

Ricinulei range from 5 to 10 mm in length. Their most notable feature is a "hood" which can be raised and lowered over the head; when lowered, it covers the mouth and the chelicerae. Ricinulei have no eyes. The pedipalps end in pincers that are small relative to their bodies, when compared to those of the related orders of scorpions and pseudoscorpions. The heavy-bodied abdomen forms a narrow pedicel, or waist, where it attaches to the prosoma. In males, the third pair of legs are modified to form copulatory organs. Malpighian tubules and a pair of coxal glands make up the excretory system. They have no lungs, as gas exchange takes place through the trachea. Superfamilies Pseudochactoidea Buthoidea Chaeriloidea Chactoidea Iuroidea Scorpionoidea See the classification sectionfor families. ... A pseudoscorpion, (also known as a false scorpion or book scorpion), is an arachnid belonging to the order Pseudoscorpionida, also known as Pseudoscorpiones or Chelonethida. ... The cephalothorax is an anatomical term used of arachnid and malacostracan arthropods for the first major body section. ... The Malpighian tubules are the insects main organ of excretion and osmoregulation, helping them to maintain water and electrolyte balance. ...

Behavior

Ricinulei are predators, feeding on other small arthropods. Little is known about their mating habits; the males have been observed using their modified third leg to transfer a spermatophore to the female. The eggs are carried under the mother's hood, until the young hatch into six-legged "larva", which later molt into their adult forms. A spermatophore is a capsule or mass created by males of various invertebrate species, containing spermatozoa and transferred in entirety to the female during sex. ...

Habitat

Ricinulei require dampness to survive.

As of 2000, approximately 55 species of ricinulei have been described worldwide, all in a single family which contains 3 genera. This article is about the year 2000. ...