Macrobiotus+richtersi+(Eutardigrada,+Macrobiotidae)

= **Macrobiotus richtersi (Eutardigrada, Macrobiotidae)** =

= Twelve species of Tardigrada are now known from Costa Rica, representing two classes, Eutardigrada and Heterotardigrada, which are further divided into two orders, Diplotardigrada and Echiniscida. These two orders split into three families the Macrobiotidae, Milnesiidae, and Echiniscidae, and finally into four genera Hypsibius, Macrobiotus, Milnesium, and Echiniscus. Macrobiotus richtersi was discoverd in the moss in Monteverde, from the Osa Peninsula in liverworts and lichens, and from Cocos Island. = = = = Macrobiotus richtersi, is a eutardigrade morphospecies with amphimictic diploid and thelytokous triploid cytotypes, was used as a model for the first attempt to define tardigrade chromosomes using banding techniques. = = = = One interesting thing about the macrobiotus richtersi is the excretory system. The excretory system of Macrobiotus richtersi consists of one dorsal and two lateral components. In each of these components there is a tricellular external lobe and a column that can be distinguished where the two parts are being connected distally. The surface of the lobe cells is increased by deep basal infoldings where it forms to a base. It also has fingerlike processes which form a maze next to the basal lamina ir what is known as the epithelium cells. Their cytoplasm contains numerous mitochondria, rough E.R., dictyosomes, and granules. Depending on the physical state of the animal it will have a certain amout of these things. At the ultrastructural level, the cytoplasm of the column shows numerous mitochondria, rough endoplasmic reticulum, lysosomes, and a well developed Golgi apparatus. The lumen of the channel is coated by glycocalyx or a certain glycoprotein. At the base of the column several small cells form the proximal part of a duct that communicates with the gut. The morphology and ultrastructure of the excretory system of M. richtersi have been compared with similar a system of a Isohypsibius megalonyx discovered by Greven in 1979. = = = = = =** //Kingdom-Animalia// ** = =** //Phylum-Tardigrada// **= =** //Class-// **Eutardigrada = =Order-Parachela = = Family- **Macrobiotidae** = =** //Genus-// **** Macrobiotus **= =** //Species-// **** richtersi **= = = = =



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