(Dicyemida)
Dicyemids
Дицієміди
Dicyemida, also known as Rhombozoa, is a phylum of tiny parasites that live in the renal appendages of cephalopods. Adult dicyemids range in length from 0.5 to 7 mm, and they can be easily viewed through a light microscope. Dicyemida lack respiratory, circulatory, excretory, digestive, and nervous systems.
The organism’s structure is simple: a single axial cell is surrounded by a jacket of twenty to thirty ciliated cells. The anterior region of the organism is termed a calotte and functions to attach the parasite to folds on the surface of its host’s renal appendages. When more than one species of dicyemida exist within the same host, they have distinctly shaped calottes, which range in shape from conical to disk shaped, or cap shaped. To this day, there has never been a recorded case of two separate species of dicyemida existing in the same host and having exactly the same calotte.
Some part of the dicyemid life cycle may be tied to temperate benthic environments, where they occur in greatest abundance. While dicyemids have occasionally been found in the tropics, the infection rates are typically quite low, and many potential host species are not infected. Dicyemids have never been reported from truly oceanic cephalopods, who instead host a parasitic ciliate fauna.
The phylum contains three families, Conocyemidae, Dicyemidae and Kantharellidae.
Conocyemidae: Conocyema polymorpha, Conocyema deca, Microcyema vespa.
Dicyemidae: Dicyema microcephalum, Dicyema moschatum, Dicyema shorti, Dicyema acciaccatum, Dicyema acheroni, Dicyema aegira, Dicyema apalachiensis, Dicyema australis, Dicyema balamuthi, Dicyema banyulensis, Dicyema benedeni, Dicyema benthoctopi, Dicyema bilobum, Dicyema caudatum, Dicyema ganapatii, Dicyema colurum, Dicyema erythrum, Dicyema dolichocephalum. Dicyema sphyrocephalum, Dicyema lycidoeceum, Dicyema hadrum, Dicyema rhadinum, Dicyema hypercephalum, Dicyema robsonellae, Dicyema knoxi, Dicyema maorum, Dicyema madrasensis, Dicyema octopusi, Dicyema nouveli, Dicyema monodi, Dicyema oligomerum, Dicyema misakiense, Dicyema orientale, Dicyema plathycephalum, Dicyema typoides, Dicyema whitmani, Dicyema sullivani, Dicyema briarei, Dicyema megalocephalum, Dicyema typus, Dicyema acuticephalum, Dicyema apollyoni, Dicyema paradoxum, Dicyema japonicum, Dicyema clavatum, Dicyema schulzianum, Dicyema rondeletiolae, Dicyema macrocephalum, Pseudicyema nakaoi, Pseudicyema truncatum, Dicyemennea gyrinodes, Dicyemennea ophioides, Dicyemennea trochocephalum, Dicyemennea mastigoides, Dicyemennea minabense, Dicyemennea granularis, Dicyemennea abelis, Dicyemennea adscita, Dicyemennea abasi, Dicyemennea abbreviata, Dicyemennea bathybenthum, Dicyemennea lameerei, Dicyemennea antarcticensis, Dicyemennea abreida, Dicyemennea brevicephala, Dicyemennea californica, Dicyemennea filiformis, Dicyemennea rossiae, Dicyemennea brevicephaloides, Dicyemennea longinucleata, Dicyemennea longinucleata, Dicyemennea kaikouriensis, Dicyemennea rostrata, Dicyemennea eltanini, Dicyemennea littlei, Dicyemennea discocephala, Dicyemennea coromandelensis, Dicyemennea eledones, Dicyemennea gracile, Dicyemennea dogieli, Dicyemennea dorycephalum, Dicyemennea canadensis, Dicyemennea adminicula, Dicyemennea parva, Dicyemennea marplatensis, Dicyemennea nouveli, Dicyemodeca anthinocephalum, Dicyemodeca sceptrum, Dicyemodeca dogieli, Pleodicyema delamarie, Dodecadicyema loligoi.
Katharellidae: Kantharella antarctica
