Perch is a common name for freshwater fish from the genus Perca, which belongs to the family Percidae of the large order Perciformes. The name comes from Greek: πέρκη, romanized: perke, meaning the type species of this genus, the European perch.
Planarians (triclads) are free-living flatworms of the class Turbellaria, order Tricladida, which includes hundreds of species, found in freshwater, marine, and terrestrial habitats. Planarians are characterized by a three-branched intestine, including a single anterior and two posterior branches. Their body is populated by adult stem cells called neoblasts, which planarians use for regenerating missing body parts. Many species are able to regenerate any missing organ, which has made planarians a popular model in research of regeneration and stem cell biology. The genome sequences of several species are available, as are tools for molecular biology analysis.
The Turbellaria are one of the traditional sub-divisions of the phylum Platyhelminthes (flatworms), and include all the sub-groups that are not exclusively parasitic. There are about 4,500 species, which range from 1 mm (0.039 in) to large freshwater forms more than 500 mm (20 in) long or terrestrial species like Bipalium kewense which can reach 600 mm (24 in) in length. All the larger forms are flat with ribbon-like or leaf-like shapes, since their lack of respiratory and circulatory systems means that they have to rely on diffusion for internal transport of metabolites. However, many of the smaller forms are round in cross section. Most are predators, and all live in water or in moist terrestrial environments. Most forms reproduce sexually and with few exceptions all are simultaneous hermaphrodites.
The order Notostraca, containing the single family Triopsidae, is a group of crustaceans known as tadpole shrimp or shield shrimp. The two genera, Triops and Lepidurus, are considered living fossils, with similar forms having existed since the end of the Devonian, around 360 million years ago. They have a broad, flat carapace, which conceals the head and bears a single pair of compound eyes. The abdomen is long, appears to be segmented and bears numerous pairs of flattened legs. The telson is flanked by a pair of long, thin caudal rami. Phenotypic plasticity within taxa makes species-level identification difficult, and is further compounded by variation in the mode of reproduction. Notostracans are omnivores living on the bottom of temporary pools and shallow lakes.
Dugesia is a genus of dugesiid triclads that contains some common representatives of the class Turbellaria. These common flatworms are found in freshwater habitats of Africa, Eurasia, and Australia. Dugesia is best known to non-specialists because of its regeneration capacities.
Dugesiidae is a family of freshwater planarians distributed worldwide. The type genus is Dugesia Girard, 1850.
Dugesia tubqalis is a species of dugesiid triclad that inhabits springs of Morocco. It is named after the Toubkal peak, the highest in the Atlas Mountains. It has been found between 1,702 and 2,164 m of altitude.
Dugesia sicula is a species of dugesiid triclad that lives in freshwater bodies of the Mediterranean Basin, where it is widely distributed. It has been reported from Sicily, Elba and Mallorca, Eivissa, Sardinia, Algeria, Tunisia, Morocco and Crete.
Girardia tigrina, known as the brown planarian or the immigrant triclad flatworm, is a species of dugesiid native to the Americas. It has been accidentally introduced into Europe and Japan.
Dugesia japonica is a species of freshwater planarian that inhabits freshwater bodies of East Asia, including Japan, Korea, Taiwan, China and northeastern Siberia. However, molecular studies suggest that Dugesia japonica is polyphyletic and different populations across its area of occurrence constitute distinct species.
Schmidtea polychroa is a species of freshwater flatworm, a dugesiid triclad that inhabits the shallow mesotrophic or eutrophic waters of rivers and lakes of Europe. It is also present in North America, where it has been introduced at least in the Saint Lawrence river system. It is an animal with a limited dispersion capability.
Dugesia artesiana is a species of dugesiid triclad found in Queensland, Australia.
Dugesia afromontana is a species of dugesiid triclad found in the Amatola Mountains, Eastern Cape, South Africa.
Dugesia burmaensis is a species of freshwater dugesiid found in Burma. The species was described from six individuals collected from Inle Lake, Shan State.
Bdellocephala is a genus of freshwater triclad that inhabits different regions of Eurasia.
The reproductive system of planarians is broadly similar among different families, although the associated structures can vary in complexity.
Protopone is an extinct genus of ants in the formicid subfamily Ponerinae described from fossils found in Europe and Asia. There are seven described species placed into the genus, Protopone? dubia, Protopone germanica, Protopone magna, Protopone oculata, Protopone primigena, Protopone sepulta, and Protopone vetula. Protopone is one several Lutetian Ponerinae genera.
Odontomachus paleomyagra is an extinct species of formicid in the ant subfamily Ponerinae known from a Miocene fossil found in Europe.
Bdellocephala annandalei is a species of freshwater triclad in the family Dendrocoelidae.
Dugesia aethiopica is a species of freshwater dugesiid planarian found in Lake Tana in Ethiopia.
