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57-521: Sumte is located in 3 km distance of the river Elbe which would flood the area several times a year without levee. The Sumte area is characterized by wet grassland and fertile fields. Furthermore, the embarkment of the Elbe river resulted in several oxbow lakes of which the Lake Sumte is the biggest. The Sumte area has historically always been a rural territory. The nearest city with more than 100 000 inhabitants

114-734: A hydrofoil . Some have a mouth that can expand to a large size and contains no incisiform teeth; catfish generally feed through suction or gulping rather than biting and cutting prey. Some families, though, notably the Loricariidae and Astroblepidae , have a suckermouth that allows them to fasten themselves to objects in fast-moving water. Catfish also have a maxilla reduced to a support for barbels ; this means that they are unable to protrude their mouths as other fish such as carp . Catfish may have up to four pairs of barbels - nasal, maxillary (on each side of mouth), and two pairs of chin barbels, though pairs of barbels may be absent depending on

171-435: A balance between them if they are to survive and thrive. Ambient temperature has been shown to affect and even convert nocturnal animals to diurnality as it is a way for them to conserve metabolic energy. Nocturnal animals are often energetically challenged due to being most active in the nighttime when ambient temperatures are lower than through the day, and so they lose a lot of energy in the form of body heat. According to

228-459: A bullhead catfish by the nickname "chucklehead", while in another state or region, that nickname refers to the blue catfish. Representatives of the genus Ictalurus have been introduced into European waters in the hope of obtaining a sporting and food resource, but the European stock of American catfishes has not achieved the dimensions of these fish in their native waters and have only increased

285-468: A catfish weighing 88 kilograms (194 lb) was caught in the River Ebro , Spain, by an 11-year-old British schoolgirl. Diurnality Diurnality is a form of plant and animal behavior characterized by activity during daytime , with a period of sleeping or other inactivity at night . The common adjective used for daytime activity is " diurnal ". The timing of activity by an animal depends on

342-495: A challenge, apart from the obvious increased activity levels during the day time light. Initially, most animals were diurnal, but adaptations that allowed some animals to become nocturnal is what helped contribute to the success of many, especially mammals. This evolutionary movement to nocturnality allowed them to better avoid predators and gain resources with less competition from other animals. This did come with some adaptations that mammals live with today. Vision has been one of

399-478: A defense, these spines may be locked into place so that they stick outwards, enabling them to inflict severe wounds. In numerous catfish species, these fin rays can be used to deliver a stinging protein if the fish is irritated; as many as half of all catfish species may be venomous in this fashion, making the Siluriformes overwhelmingly the vertebrate order with the largest number of venomous species. This venom

456-474: A diverse group of ray-finned fish . Named for their prominent barbels , which resemble a cat 's whiskers , catfish range in size and behavior from the three largest species alive, the Mekong giant catfish from Southeast Asia , the wels catfish of Eurasia , and the piraíba of South America , to detritivores (species that eat dead material on the bottom), and even to a tiny parasitic species commonly called

513-495: A juvenile obaichthyid lepisosteiform , possibly a junior synonym of Obaichthys . The authors of the original study still stood by their original conclusion based on the absence of important holostean characters, and noted that it could not be a juvenile, since the bones were completely ossified. The taxonomy of catfish is quickly changing. In a 2007 and 2008 paper, Horabagrus , Phreatobius , and Conorhynchos were not classified under any current catfish families. There

570-826: A rate three times faster than that of the past century. In June 2005, researchers named the newest family of catfish, Lacantuniidae , only the third new family of fish distinguished in the last seventy years, the others being the coelacanth in 1938 and the megamouth shark in 1983. The new species in Lacantuniidae , Lacantunia enigmatica , was found in the Lacantun river in the Mexican state of Chiapas . The higher-level phylogeny of Siluriformes has gone through several recent changes, mainly due to molecular phylogenetic studies. While most studies, both morphological and molecular, agree that catfishes are arranged into three main lineages ,

627-536: A result of long branch attraction , incorrectly placing Loricarioidei as the earliest-branching catfish lineage. When a data filtering method was used to reduce lineage rate heterogeneity (the potential source of bias) on their dataset, a final phylogeny was recovered which showed the Diplomystidae are the earliest-branching catfish, followed by Loricarioidei and Siluroidei as sister lineages, providing both morphological and molecular support for Diplomystidae being

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684-421: A variety of environmental factors such as the temperature, the ability to gather food by sight, the risk of predation, and the time of year. Diurnality is a cycle of activity within a 24-hour period; cyclic activities called circadian rhythms are endogenous cycles not dependent on external cues or environmental factors except for a zeitgeber . Animals active during twilight are crepuscular , those active during

741-557: Is Phreatobius cisternarum , known to live underground in phreatic habitats. Numerous species from the families Ariidae and Plotosidae , and a few species from among the Aspredinidae and Bagridae , are found in salt water. In the Southern United States, catfish species may be known by a variety of slang names, such as "mud cat", "polliwogs", or "chuckleheads". These nicknames are not standardized, so one area may call

798-454: Is Hamburg in 65 km distance (city center). The first documented mentioning of Sumte dates back as early as 1352 as Zommete, which is of Slavic origin and means catfish . The name indicates a founding of the village by Slavic people as fisherman's settlement. At times of the German eastward expansion German settlers mixed with the ancestral Slavic people and the old German village of Sumte

855-455: Is also limited, meaning the risks of predation are less than the risk of freezing or starving to death. Many plants are diurnal or nocturnal, depending on the time period when the most effective pollinators, i.e., insects, visit the plant. Most angiosperm plants are visited by various insects, so the flower adapts its phenology to the most effective pollinators. Thus, the effectiveness of relative diurnal or nocturnal species of insects affects

912-593: Is disagreement on the family status of certain groups; for example, Nelson (2006) lists Auchenoglanididae and Heteropneustidae as separate families, while the All Catfish Species Inventory (ACSI) includes them under other families. FishBase and the Integrated Taxonomic Information System lists Parakysidae as a separate family, while this group is included under Akysidae by both Nelson (2006) and ACSI. Many sources do not list

969-505: Is one of the strongest influences of the suprachiasmatic nucleus (SCN) which is part of the hypothalamus in the brain that controls the circadian rhythm in most animals. This is what determines whether an animal is diurnal or not. The SCN uses visual information like light to start a cascade of hormones that are released and work on many physiological and behavioural functions. Light can produce powerful masking effects on an animal's circadian rhythm, meaning that it can "mask" or influence

1026-476: Is produced by glandular cells in the epidermal tissue covering the spines. In members of the family Plotosidae and of the genus Heteropneustes , this protein is so strong it may hospitalize humans who receive a sting; in Plotosus lineatus , the stings can be lethal. The dorsal- and pectoral-fin spines are two of the most conspicuous features of siluriforms, and differ from those in other fish groups. Despite

1083-570: Is usually considered to be the earliest branching catfish lineage and the sister group to the other two lineages, Loricarioidei and Siluroidei. Molecular evidence usually contrasts with this hypothesis, and shows the suborder Loricarioidei as the earliest branching catfish lineage, and sister to a clade that includes the Diplomystidae and Siluroidei; this phylogeny has been obtained in numerous studies based on genetic data. However, it has been suggested that these molecular results are errors as

1140-776: The Cypriniformes (carps and minnows), Characiformes (characins and tetras), Gonorynchiformes (milkfish and beaked salmons) and Gymnotiformes (South American knifefish), a superorder characterized by the Weberian apparatus . Some place Gymnotiformes as a sub-order of Siluriformes; however, this is not as widely accepted. Currently, the Siluriformes are said to be the sister group to the Gymnotiformes, though this has been debated due to more recent molecular evidence. As of 2007 there were about thirty-six extant catfish families, and about 3,093 extant species have been described. This makes

1197-520: The Gran Chaco in South America showed that increased amounts of moonlight at night increased their activity levels through the night which led to a decrease of daytime activity. Meaning that for this species, ambient moonlight is negatively correlated with diurnal activity. This is also connected with the foraging behaviours of the monkeys, as when there were nights of little to no moonlight, it affected

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1254-556: The Hamburg Metropolitan Region lead to an economic recovery of the Sumte region. In October 2015 plans became public that the government of Lower Saxony plans to set up a refugee transit camp with up to 1000 refugees. These plans made Sumte worldwide famous, since the ratio of 10 refugees versus 1 inhabitant would have been unique in a developed country. After close inspection of the local infrastructure and two townhall meetings,

1311-766: The Late Cretaceous , including the Andinichthyidae , Vorhisia vulpes and possibly Arius . A potential fossil record is known from the earlier Coniacian - Santonian stages in Niger of West Africa , though this has been considered unreliable, and the putative earliest armored catfish known from the fossil record, Afrocascudo , lived during the Cenomanian age of the Late Cretaceous in Morocco of North Africa ( Kem Kem Group ). The describers of Afrocascudo claimed that

1368-418: The candiru , Vandellia cirrhosa . Neither the armour-plated types nor the naked types have scales. Despite their name, not all catfish have prominent barbels or "whiskers". Members of the Siluriformes order are defined by features of the skull and swimbladder . Catfish are of considerable commercial importance; many of the larger species are farmed or fished for food. Many of the smaller species, particularly

1425-430: The night-blooming cereus opens at night to attract large sphinx moths . Many types of animals are classified as being diurnal, meaning they are active during the day time and inactive or have periods of rest during the night time. Commonly classified diurnal animals include mammals , birds , and reptiles . Most primates are diurnal, including humans . Scientifically classifying diurnality within animals can be

1482-510: The Americas. They are the only ostariophysans that have entered freshwater habitats in Madagascar , Australia, and New Guinea . They are found in fresh water/ brackish water environments, though most inhabit shallow, running water. Representatives of at least eight families are hypogean (live underground) with three families that are also troglobitic (inhabiting caves). One such species

1539-474: The German reunification in 1990, people raised their voices for a small reunifaction, which means they wanted to belong to Hannover again, which now was the state of Lower Saxony. In 1993, the two federal states Mecklenburg Western Pomerania , which was newly formed and Lower Saxony signed a treaty to exchange the territory of Amt Neuhaus and thus Sumte belonged to Hannover again. The proximity to Lüneburg and to

1596-538: The ariid catfish, where the young retain yolk sacs late into juvenile stages, and many pimelodids, which may have elongated barbels and fin filaments or coloration patterns. Sexual dimorphism is reported in about half of all families of catfish. The modification of the anal fin into an intromittent organ (in internal fertilizers) as well as accessory structures of the reproductive apparatus (in both internal and external fertilizers) have been described in species belonging to 11 different families. Catfish have one of

1653-464: The armor is formed solely by expanded vertebral processes that form plates. Finally, the lateral armor of doradids , Sisor , and hoplomyzontines consists of hypertrophied lateral line ossicles with dorsal and ventral lamina . All catfish other than members of the Malapteruridae ( electric catfish ), possess a strong, hollow, bony, leading spine-like ray on their dorsal and pectoral fins . As

1710-508: The catfish order the second or third most diverse vertebrate order; in fact, one out of every twenty vertebrate species is a catfish. Catfish are believed to have a Gondwanan origin primarily centered around South America, as the most basal living catfish groups are known from there. The earliest known definitive members lived in the Americas from the Campanian to Maastrichtian stages of

1767-454: The circadian thermos-energetics (CTE) hypothesis, animals that are expending more energy than they are taking in (through food and sleep) will be more active in the light cycle, meaning they will be more active in the day. This has been shown in studies done on small nocturnal mice in a laboratory setting. When they were placed under a combination of enough cold and hunger stress, they converted to diurnality through temporal niche switching, which

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1824-400: The day, and therefore conserve more energy, especially when colder seasonal temperatures hit. Light is one of the most defining environmental factors that determines an animal's activity pattern. Photoperiod or a light dark cycle is determined by the geographical location, with day time being associated with much ambient light, and night time being associated with little ambient light. Light

1881-420: The diurnal or nocturnal nature of the plants they pollinate, causing in some instances an adjustment of the opening and closing cycles of the plants. For example, the baobab is pollinated by fruit bats and starts blooming in late afternoon; the flowers are dead within twenty-four hours. Services that alternate between high and low utilization in a daily cycle are described as being diurnal. Many websites have

1938-1524: The earliest branching catfish. Below is a list of family relationships by different authors. Lacantuniidae is included in the Sullivan scheme based on recent evidence that places it sister to Claroteidae . Phylogeny of living Siluriformes based on 2017 and extinct families based on Nelson, Grande & Wilson 2016. † Andinichthyidae Nematogenyidae [REDACTED] Trichomycteridae [REDACTED] Callichthyidae [REDACTED] Astroblepidae [REDACTED] Loricariidae [REDACTED] Diplomystidae † Bachmanniidae † Hypsidoridae Cetopsidae [REDACTED] Siluridae [REDACTED] Pangasiidae Mochokidae [REDACTED] Claroteidae Plotosidae Ictaluridae [REDACTED] Clariidae [REDACTED] Ailiidae Sisoridae [REDACTED] Bagridae [REDACTED] Aspredinidae Doradidae [REDACTED] Auchenipteridae [REDACTED] Heptapteridae [REDACTED] Pseudopimelodidae [REDACTED] Pimelodidae [REDACTED] Unassigned families: Extant catfish species live inland or in coastal waters of every continent except Antarctica . Catfish have inhabited all continents at one time or another. They are most diverse in tropical South America, Asia, and Africa, with one family native to North America and one family in Europe. More than half of all catfish species live in

1995-429: The ecological pressure on native European fauna . Walking catfish have also been introduced in the freshwater areas of Florida, with the voracious catfish becoming a major alien pest there. Flathead catfish , Pylodictis olivaris , is also a North American pest on Atlantic slope drainages. Pterygoplichthys species, released by aquarium fishkeepers, have also established feral populations in many warm waters around

2052-439: The evolution of diurnality. With about 20 transitions counted for the gecko lineages, it shows the significance of diurnality. Strong environmental influences like climate change, predation risk, and competition for resources are all contributing factors. Using the example of geckos, it is thought that species like Mediodactylus amictopholis that live at higher altitudes have switched to diurnality to help gain more heat through

2109-439: The former ranges throughout Europe, and the latter is restricted to Greece . Mythology and literature record wels catfish of astounding proportions yet are to be proven scientifically. The typical size of the species is about 1.2–1.6 m (3.9–5.2 ft), and fish more than 2 m (6.6 ft) are rare. However, they are known to exceed 2.5 m (8.2 ft) in length and 100 kg (220 lb) in weight. In July 2009,

2166-487: The genus Corydoras , are important in the aquarium hobby . Many catfish are nocturnal , but others (many Auchenipteridae ) are crepuscular or diurnal (most Loricariidae or Callichthyidae , for example). Molecular evidence suggests that in spite of the great morphological diversity in the order, all catfish form a monophyletic group. Catfish belong to a superorder called the Ostariophysi , which also includes

2223-456: The genus is possible. As far as known for most catfish, features that are often characteristic of species, such as mouth and fin positions, fin shapes, and barbel lengths, show little difference between juveniles and adults. For many species, pigmentation pattern is also similar in juveniles and adults. Thus, juvenile catfish generally resemble and develop smoothly into their adult form without distinct juvenile specializations. Exceptions to this are

2280-416: The internal clock, changing the activity patterns of an animal, either temporarily or over the long term if exposed to enough light over a long period of time. Masking can be referred to either as positive masking or negative masking, with it either increasing an diurnal animals activity or decreasing a nocturnal animal's activity, respectively. This can be depicted when exposing different types of rodents to

2337-404: The largest ranges in size within a single order of bony fish . Many catfish have a maximum length of under 12 cm (4.7 in). Some of the smallest species of the Aspredinidae and Trichomycteridae reach sexual maturity at only 1 cm (0.39 in). The wels catfish , Silurus glanis , and the much smaller related Aristotle's catfish , are the only catfish indigenous to Europe ;

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2394-518: The maximum number of refugees was reduced to 750. On 2 November 2015 the first 100 refugees arrived in Sumte. Locals and the ASB as operator of the camp, installed a shop, a kindergarten and a medical station within the refugee camp, which can be used by inhabitants of Sumte as well. Catfish Extant families: Extinct family: Catfish (or catfishes ; order Siluriformes / s ɪ ˈ lj ʊər ɪ f ɔːr m iː z / or Nematognathi ) are

2451-604: The monkey's ability to forage efficiently, so they were forced to be more active in the day to find food. Diurnality has shown to be an evolutionary trait in many animal species, with diurnality mostly reappearing in many lineages. Other environmental factors like ambient temperature, food availability, and predation risk can all influence whether an animal will evolve to be diurnal, or if their effects are strong enough, then mask over their circadian rhythm, changing their activity patterns to becoming diurnal. All three factors often involve one another, and animals need to be able to find

2508-568: The most common transitions. Still today, diurnality seems to be reappearing in many lineages of other animals, including small rodent mammals like the Nile grass rat and golden mantle squirrel and reptiles. More specifically, geckos, which were thought to be naturally nocturnal have shown many transitions to diurnality, with about 430 species of geckos now showing diurnal activity. With so many diurnal species recorded, comparative analysis studies using newer lineages of gecko species have been done to study

2565-767: The most greatly affected senses from switching back and forth from diurnality to nocturnality, and this can be seen using biological and physiological analysis of rod nuclei from primate eyes. This includes losing two of four cone opsins that assists in colour vision , making many mammals dichromats . When early primates converted back to diurnality, better vision that included trichromatic colour vision became very advantageous, making diurnality and colour vision adaptive traits of simiiformes , which includes humans. Studies using chromatin distribution analysis of rod nuclei from different simian eyes found that transitions between diurnality and nocturnality occurred several times within primate lineages, with switching to diurnality being

2622-415: The night are nocturnal and animals active at sporadic times during both night and day are cathemeral . Plants that open their flowers during the daytime are described as diurnal, while those that bloom during nighttime are nocturnal. The timing of flower opening is often related to the time at which preferred pollinators are foraging. For example, sunflowers open during the day to attract bees, whereas

2679-566: The order. In loricarioids and in the Asian genus Sisor , the armor is primarily made up of one or more rows of free dermal plates. Similar plates are found in large specimens of Lithodoras . These plates may be supported by vertebral processes , as in scoloplacids and in Sisor , but the processes never fuse to the plates or form any external armor. By contrast, in the subfamily Doumeinae (family Amphiliidae ) and in hoplomyzontines ( Aspredinidae ),

2736-467: The presence of a Weberian apparatus . Their well-developed Weberian apparatus and reduced gas bladder allow for improved hearing and sound production. Catfish do not have scales ; their bodies are often naked. In some species, their mucus -covered skin is used in cutaneous respiration , where the fish breathes through its skin. In some catfish, the skin is covered in bony plates called scutes ; some form of body armor appears in various ways within

2793-510: The presence of a derived loricariid so early on would indicate the extensive diversification of catfish, or at least loricarioids, prior to the beginning of the Late Cretaceous. As extant loricariids are only known from South America, much of this diversification must have occurred on the supercontinent of West Gondwana prior to its fragmentation into South America and Africa. Britz and colleagues suggested that Afrocascudo instead represents

2850-430: The recently revised family Anchariidae . The family Horabagridae , including Horabagrus , Pseudeutropius , and Platytropius , is not shown by some authors but presented by others as a true group. Thus, the actual number of families differs between authors. The species count is in constant flux due to taxonomic work as well as description of new species. Between 2003 and 2005, over one hundred species were named,

2907-501: The relationship among these lineages has been a contentious point in which these studies, performed for example by Rui Diogo , differ. The three main lineages in Siluriformes are the family Diplomystidae , the denticulate catfish suborder Loricarioidei (containing the Neotropical "suckermouth" catfishes), and the suborder Siluroidei, which contains the remaining families of the order. According to morphological data, Diplomystidae

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2964-439: The same photoperiods. When a diurnal Nile grass rat and nocturnal mouse are exposed to the same photoperiod and light intensity, increased activity occurred within the grass rat (positive masking), and decreased activity within the mouse (negative masking). Even small amounts of environmental light change have shown to have an effect on the activity of mammals. An observational study done on the activity of nocturnal owl monkeys in

3021-475: The species. Catfish barbels always occur in pairs. Many larger catfish also have chemoreceptors across their entire bodies, which means they "taste" anything they touch and "smell" any chemicals in the water. "In catfish, gustation plays a primary role in the orientation and location of food". Because their barbels and chemoreception are more important in detecting food, the eyes on catfish are generally small. Like other ostariophysans , they are characterized by

3078-599: The widespread use of the spines for taxonomic and phylogenetic studies the fields have struggled to effectively use the information due to a lack of consistency in the nomenclature, with a general standard for the descriptive anatomy of catfish spines proposed in 2022 to try and resolve this problem. Juvenile catfish, like most fish, have relatively large heads, eyes, and posterior median fins in comparison to larger, more mature individuals. These juveniles can be readily placed in their families, particularly those with highly derived fin or body shapes; in some cases, identification of

3135-428: The world. Most catfish are bottom feeders . In general, they are negatively buoyant , which means that they usually sink rather than float due to a reduced gas bladder and a heavy, bony head. Catfish have a variety of body shapes, though most have a cylindrical body with a flattened ventrum to allow for benthic feeding. A flattened head allows for digging through the substrate, as well as perhaps serving as

3192-407: Was expected. Another similar study that involved energetically challenging small mammals showed that diurnality is most beneficial when the animal has a sheltered location to rest in, reducing heat loss. Both studies concluded that nocturnal mammals do change their activity patterns to be more diurnal when energetically stressed (due to heat loss and limited food availability), but only when predation

3249-686: Was formed. Sumte belonged to the Kingdom of Hanover until it became Prussian province in 1871. After world war II Sumte belonged to the British occupation zone but was resigned to the Soviets , since it was the only territory in the British zone east of the river Elbe and the upkeep costs of this bridgehead would have been too high. Therefore, Sumte became part of the Soviet controlled German Democratic Republic . After

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