Pentastomida

The tongue worms, a group of parasitic wormlike animals considered to form a distinct phylum thought to be descended from primitive arthropods, though modified by parasitism to form elongate, pseudosegmented, wormlike organisms with two to three pairs of budlike degenerate limbs in the larva and anterior, hollow, fanglike hooks in the adult. Adults are usually parasitic in the lungs or respiratory tract of vertebrates, usually in snakes and other reptiles, though one group parasitizes the air sacs of birds and one family (Linguatulidae) has become adapted to the lungs of mammal carnivores (families Felidae and Canidae). Larvae are found in the viscera of many hosts that serve as prey of the final hosts (insects, fish, amphibians, chiefly frogs, and mammals, chiefly rodents). Dogs may develop adult Linguatula serrata in their nasal passages from infective larvae (nymphs) in the viscera of sheep, cattle, or rabbits, which became infected from water or vegetation contaminated with eggs passed by infected dogs; humans also can develop a larval infection from this source. Human infection of liver, spleen, and lungs has been reported in Africa from Armillifer armillatus and in China by A. moniliformis from contaminated water or vegetation or from handling infected snakes. [see Pentastoma]

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Pen·ta·stom·i·da .pent-ə-'stäm-əd-ə n pl any of a group of parasitic animals that are considered a class of the phylum Arthropoda or a separate phylum, that lack eyes, a circulatory system, and a respiratory system, that live as adults in the respiratory passages or body cavity of reptiles, birds, or mammals and undergo larval development in similar hosts, and that comprise the tongue worms

pen·tas·to·mid pen-'tas-tə-məd n

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Pen·ta·sto·mida (pen″tə-stoґmid-ə) the tongue worms, a small phylum that was formerly considered part of Arthropoda, consisting of degenerate wormlike parasites that lack circulatory and respiratory systems. Adults do not have appendages, but have two pairs of hooks near the mouth, and larvae have two or three pairs of rudimentary legs. Adults live in the respiratory passages and body cavities of reptiles, birds, and mammals. Families of importance in human and veterinary medicine include Porocephalidae and Linguatulidae.