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Cavernicola (worm)
Cavernicola is a suborder of planarians found mostly in freshwater habitats of caves, although some species occur on the surface. Description The main morphological feature that defines the suborder Cavernicola is the placement of their ovaries. They are located more posteriorly than in other planarians, which usually have them close to the brain. The copulatory apparatus has a copulatory bursa in most species, although in some it is absent and is replaced by a connection to the intestine. Taxonomy The suborder Cavernicola was originally erected for the family Dimarcusidae Dimarcusidae is a family of triclads found mostly in freshwater habitats of caves, although at least one species, '' Rhodax evelinae'', occurs in surface waters. Currently the family contains only seven species distributed in five genera, althou ... due to its unusual morphological features that did not match those of the other planarian suborders. Recently, the discovery of another unusual cave spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hausera Hauseri
''Hausera'' is a subterranean genus of planarian from Brazil. It contains only the single species ''Hausera hauseri''. It is the first cave-dwelling member of the suborder Cavernicola to have been observed in South America. Etymology Both the genus and species were named after Josef Hauser, a researcher of freshwater flatworms. Description Specimens are long and wide. The pharynx is long, and along with the gonopore is located in the hindmost third of the body. While it lacks eyes, the head has a pair of ciliated sensory organs approximately 140 µm back from the body's anterior end. The intestine extends into the brain and connects with the reproductive system via a genito-intestinal duct. The testicular follicles are arranged in uneven rows near the margins of the body, and the ovaries are located behind but in proximity to the brain, approximately 0.6 millimeters behind the body's tip. The species is colorless. Range and habitat ''Hausera hauseri'' was found in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimarcusidae
Dimarcusidae is a family of triclads found mostly in freshwater habitats of caves, although at least one species, '' Rhodax evelinae'', occurs in surface waters. Currently the family contains only seven species distributed in five genera, although the total number of species is thought to be much higher. Description The morphological features uniting species of Dimarcusidae are related to the reproductive system The reproductive system of an organism, also known as the genital system, is the biological system made up of all the anatomical organs involved in sexual reproduction. Many non-living substances such as fluids, hormones, and pheromones are als .... Their ovaries are located more posteriorly than in most triclads, which usually have them close to the brain. The penis in species of Dimarcusidae contains glandular elements and the common ovovitelline duct is perpendicular to the female genital duct. Taxonomy The family Dimarcusidae was erected in 1972 by Mitchell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suborder
Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized by the nomenclature codes. An immediately higher rank, superorder, is sometimes added directly above order, with suborder directly beneath order. An order can also be defined as a group of related families. What does and does not belong to each order is determined by a taxonomist, as is whether a particular order should be recognized at all. Often there is no exact agreement, with different taxonomists each taking a different position. There are no hard rules that a taxonomist needs to follow in describing or recognizing an order. Some taxa are accepted almost universally, while others are recognized only rarely. The name of an order is usually written with a capital letter. For some groups of organisms, their orders may follow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planarian
A planarian is one of the many flatworms of the traditional class Turbellaria. It usually describes free-living flatworms of the order Tricladida (triclads), although this common name is also used for a wide number of free-living platyhelminthes. Planaria are common to many parts of the world, living in both saltwater and freshwater ponds and rivers. Some species are terrestrial and are found under logs, in or on the soil, and on plants in humid areas. The triclads are characterized by triply branched intestine and anteriorly situated ovaries, next to the brain. Today the order Tricladida is split into three suborders, according to their phylogenetic relationships: Maricola, Cavernicola and Continenticola. Formerly, the Tricladida was split according to habitats: Maricola, which is marine; Paludicola which inhabits freshwater; and Terricola, which is land-dwelling. Planaria exhibit an extraordinary ability to regenerate lost body parts. For example, a planarian split lengt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cave
A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea caves, rock shelters, and grottos, that extend a relatively short distance into the rock and they are called ''exogene'' caves. Caves which extend further underground than the opening is wide are called ''endogene'' caves. Speleology is the science of exploration and study of all aspects of caves and the cave environment. Visiting or exploring caves for recreation may be called ''caving'', ''potholing'', or ''spelunking''. Formation types The formation and development of caves is known as ''speleogenesis''; it can occur over the course of millions of years. Caves can range widely in size, and are formed by various geological processes. These may involve a combination of chemical processes, erosion by water, tectonic forces, microorgani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reproductive System Of Planarians
The reproductive system of planarians is broadly similar among different families, although the associated structures can vary in complexity. All planarians are hermaphrodites, so their reproductive system has a male and a female part. Both parts communicate with the surface of the body via a single opening called gonopore, which is located on the ventral side of the posterior half of the body. Male part of the reproductive system The male part of the reproductive system in planarians has a set of several testicles, distributed throughout the body in two or more rows. They are usually concentrated in the anterior two thirds of the body, although they can reach close to the posterior end. The testicles are connected to a pair of sperm ducts which run posteriorly towards the gonopore. In some groups, the sperm ducts met in their distal part, forming the ejaculatory duct, which then opens in a cavity called “male atrium”. In others, like land planarians, both open in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cavernicola (worm)
Cavernicola is a suborder of planarians found mostly in freshwater habitats of caves, although some species occur on the surface. Description The main morphological feature that defines the suborder Cavernicola is the placement of their ovaries. They are located more posteriorly than in other planarians, which usually have them close to the brain. The copulatory apparatus has a copulatory bursa in most species, although in some it is absent and is replaced by a connection to the intestine. Taxonomy The suborder Cavernicola was originally erected for the family Dimarcusidae Dimarcusidae is a family of triclads found mostly in freshwater habitats of caves, although at least one species, '' Rhodax evelinae'', occurs in surface waters. Currently the family contains only seven species distributed in five genera, althou ... due to its unusual morphological features that did not match those of the other planarian suborders. Recently, the discovery of another unusual cave spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
