The tropics are the regions of Earth surrounding the Equator , where the sun may shine directly overhead . This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's axial tilt ; the width of the tropics (in latitude) is twice the tilt. The tropics are also referred to as the tropical zone and the torrid zone (see geographical zone ).
38-464: Apocryptes Apocryptodon Boleophthalmus Oxuderces Parapocryptes Periophthalmodon Periophthalmus Pseudapocryptes Scartelaos Zappa Mudskippers are any of the 23 extant species of amphibious fish from the subfamily Oxudercinae of the goby family Oxudercidae . They are known for their unusual body shapes, preferences for semiaquatic habitats, limited terrestrial locomotion and jumping , and
76-511: A break in rainfall during mid-season when the Intertropical Convergence Zone or monsoon trough moves poleward of their location during the middle of the warm season; Typical vegetation in these areas ranges from moist seasonal tropical forests to savannahs . When the wet season occurs during the warm season, or summer , precipitation falls mainly during the late afternoon and early evening hours. The wet season
114-470: A crucial role in the development of the eggs within the burrow. Mudskippers are quite active when out of water, feeding and interacting with one another, for example, to defend their territories and court potential partners. Once the male has completed digging his burrow he will resurface and will begin attempting to attract a female through assorted yet typical displays. These displays consist of body undulations, different postures and energetic movements. Once
152-507: A distinct " Periophthalmus lineage", together with amblyopines. Mudskippers can be defined as oxudercine gobies that are "fully terrestrial for some portion of the daily cycle" (character 24 in Murdy, 1989). This would define the species of the genera Boleophthalmus , Periophthalmodon , Periophthalmus , and Scartelaos as "mudskippers". However, field observations of Zappa confluentus suggest that this monotypic genus should be included in
190-481: A membrane called the dermal cup rises to cover them. Although other fully aquatic goby species do not have the ability to blink, mudskippers did not evolve different muscles or glands to blink with; their blinking is accomplished with the same muscles in a different configuration. Rather than having specialized glands to produce eye lubricant, the fluid film on their cornea is likely composed of mucus secreted by their skin and water from their environment, possibly stored in
228-500: Is a time when air quality improves, freshwater quality improves and vegetation grows significantly due to the wet season supplementing flora, leading to crop yields late in the season. Floods and rains cause rivers to overflow their banks, and some animals to retreat to higher ground. Soil nutrients are washed away and erosion increases. The incidence of malaria increases in areas where the rainy season coincides with high temperatures. Animals have adaptation and survival strategies for
266-459: Is by far the most diverse and widespread genus of mudskipper. Eighteen species have been described . Periophthalmus argentilineatus is one of the most widespread and well-known species. It can be found in mangrove ecosystems and mudflats of East Africa and Madagascar east through the Sundarbans of Bengal , Southeast Asia to Northern Australia , southeast China , Taiwan , and
304-475: Is known as cutaneous respiration . Another important adaptation that aids breathing while out of water is their enlarged gill chambers, where they retain a bubble of air. These chambers close tightly when the fish is above water, due to a ventromedial valve of the gill slit, keeping the gills moist, and allowing them to function while exposed to air. Gill filaments are stiff and do not coalesce when out of water. The different species have adapted to various diets on
342-422: Is of minor importance to local commercial fisheries . It is currently the only known member of its genus . This Oxudercidae -related article is a stub . You can help Misplaced Pages by expanding it . Tropical Due to the overhead sun, the tropics receive the most solar energy over the course of the year, and consequently have the highest temperatures on the planet. Even when not directly overhead,
380-585: Is that the tropics represent a ' Garden of Eden ', a heaven on Earth, a land of rich biodiversity or a tropical paradise. The alternative is that the tropics consist of wild, unconquerable nature. The latter view was often discussed in old Western literature more so than the first. Evidence suggests over time that the view of the tropics as such in popular literature has been supplanted by more well-rounded and sophisticated interpretations. Western scholars tried to theorise why tropical areas were relatively more inhospitable to human civilisations than colder regions of
418-477: Is the only oxudercine goby that inhabits the coastal areas of western Africa. Apocryptes For genus Apocryptes For species A. bato Apocryptes bato is a species of mudskipper native to India , Bangladesh and Myanmar where it can be found in tropical rivers, estuaries and coastal waters of the Indian Ocean . This species can reach a length of 26 centimetres (10 in) TL . It
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#1732779665914456-605: The Andes as far south as the northernmost parts of Chile and Perú . The climate is changing in the tropics, as it is in the rest of the world. The effects of steadily rising concentrations of greenhouse gases on the climate may be less obvious to tropical residents, however, because they are overlain by considerable natural variability. Much of this variability is driven by the El Niño-Southern Oscillation (ENSO) . The Tropics has warmed by 0.7–0.8 °C over
494-504: The Indo - Pacific and the Atlantic coast of Africa. Compared with fully aquatic gobies, these specialised fish present a range of anatomical and ethological adaptations that allow them to move effectively on land as well as in the water. As their name implies, these fish use their fins to move around in a series of skips. Although mudskippers' fins do not have a joint homologous to
532-732: The Pantropic . The system of biogeographic realms differs somewhat; the Neotropical realm includes both the Neotropics and temperate South America, and the Paleotropics correspond to the Afrotropical , Indomalayan , Oceanian , and tropical Australasian realms . Flora are plants found in a specific region at a specific time. Some well-known plants that are exclusively found in, originate from, or are often associated with
570-620: The Ryukyus , to Samoa and Tonga Islands. It grows to a length of about 9.5 cm and is a carnivorous opportunist feeder. It feeds on small prey such as small crabs and other arthropods . However, a recent molecular study suggests that P. argentilineatus is in fact a complex of species, with at least three separate lineages, one in East Africa, and two in the Indo-Malayan region. Another species, Periophthalmus barbarus ,
608-579: The Waterberg Biosphere of South Africa , and eastern Madagascar rainforests. Often the soils of tropical forests are low in nutrient content, making them quite vulnerable to slash-and-burn deforestation techniques, which are sometimes an element of shifting cultivation agricultural systems. In biogeography , the tropics are divided into Paleotropics (Africa, Asia and Australia) and Neotropics (Caribbean, Central America, and South America). Together, they are sometimes referred to as
646-719: The axial tilt of the Earth . The Tropic of Cancer is the Northernmost latitude from which the Sun can ever be seen directly overhead , and the Tropic of Capricorn is the Southernmost. This means that the tropical zone includes everywhere on Earth which is a subsolar point at least once during the solar year . Thus the maximum latitudes of the tropics have equal distances from the equator on either side. Likewise, they approximate
684-465: The cleithrum meets the radials and an 'intra-fin' joint where the radials meet the rays. In addition, ... the abductor superficialis muscle of the pectoral fin is divided into two sections (rather than being a single muscle, as is common with the rest of the Oxudercinae gobies) with one section inserting on the dorsal rays and the other section inserting on the ventral rays. Mudskippers have
722-494: The common name ) and even climb low-hanging tree branches and scrubs . Mudskippers have also been found to be able to leap distances of up to 61 centimetres (24 in) by laterally flexing and pushing with their tails. Oxudercinae is sometimes classified within the family Gobiidae ( gobies ). Recent molecular studies do not support this classification, as oxudercine gobies appear to be paraphyletic relative to amblyopine gobies (Gobiidae: Amblyopinae ), thus being included in
760-415: The ability to breathe through their skin and the lining of their mouth (the mucosa ) and throat (the pharynx ); this is only possible when the mudskippers are wet, limiting them to humid habitats and requiring that they keep themselves moist. The ability to breathe through their skin is associated with increased capillary density in their skin. This mode of breathing, similar to that employed by amphibians ,
798-405: The ability to survive prolonged periods of time both in and out of water. Mudskippers can grow up to 30 cm (12 in) long, and most are a brownish green colour that ranges anywhere from dark to light. During mating seasons , the males will also develop brightly coloured spots in order to attract females, which can be red, green or blue. Unlike other fish, the mudskipper's eyes protrude from
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#1732779665914836-399: The angle of the Earth's axial tilt. This angle is not perfectly fixed, mainly due to the influence of the moon, but the limits of the tropics are a geographic convention, and their variance from the true latitudes is very small. Many tropical areas have both a dry and a wet season. The wet season , rainy season or green season is the time of year, ranging from one or more months when most of
874-459: The average annual rainfall in a region falls. Areas with wet seasons are disseminated across portions of the tropics and subtropics , some even in temperate regions. Under the Köppen climate classification , for tropical climates , a wet-season month is defined as one or more months where average precipitation is 60 mm (2.4 in) or more. Some areas with pronounced rainy seasons see
912-529: The definition. Mudskippers typically live in burrows in intertidal habitats , and exhibit unique adaptations to this environment that are not found in most intertidal fishes , which typically survive the retreat of the tide by hiding under wet seaweed or in tide pools . These burrows are most often characterised by their smooth and vaulted ceilings. The way the males dig these burrows has been found to be directly linked to their ability to survive submerged in almost anoxic water. It has also been found to play
950-422: The elbow, the joint between the radials and the fin rays serves a functionally analogous role. The mudskipper pectoral fin differs from most actinopterygian fishes in that the radials of the mudskipper pectoral fin are elongated and protrude from the body wall. This unusual morphology creates a pectoral fin with two fin segments (the radials and the rays) and two movable hinge joints: a 'shoulder' joint where
988-426: The female has made her choice she will then proceed to follow the male into the burrow where she will lay hundreds of eggs and allow them to be fertilized. After fertilization occurs, the period of cohabitation between the male and female is rather short. Eventually, the female will leave and it is the male that ends up guarding the egg filled burrow from hungry predators. Mudskippers are amphibious. When leaving
1026-460: The geographic region; these usages ought not be confused. The Earth's axial tilt is currently around 23.4° , and therefore so are the latitudes of the tropical circles , marking the boundary of the tropics: specifically, ±23°26′09.8″ (or 23.43605°). The northern one is called the Tropic of Cancer , and the southern is the Tropic of Capricorn . As the Earth's axial tilt changes, so too do
1064-554: The infraorbital space behind the dermal cup membrane. Mudskippers likely evolved blinking in response to conditions of terrestrial life, such as to keep their eyes wet out of water (they blink more frequently in high evaporation conditions and only when colliding with things in water) and to clean and protect the eye from debris, which may adhere to the eye or approach at a faster, more dangerous speed when in air versus when in water. Their eyes are not elevated when they are still juveniles, which are fully aquatic. The genus Periophthalmus
1102-961: The last century—only slightly less than the global average—but a strong El Niño made 1998 the warmest year in most areas, with no significant warming since. Climate models predict a further 1–2 °C warming by 2050 and 1–4 °C by 2100. Tropical plants and animals are those species native to the tropics. Tropical ecosystems may consist of tropical rainforests , seasonal tropical forests , dry (often deciduous) forests , spiny forests, deserts , savannahs, grasslands and other habitat types. There are often wide areas of biodiversity , and species endemism present, particularly in rainforests and seasonal forests. Some examples of important biodiversity and high-endemism ecosystems are El Yunque National Forest in Puerto Rico , Costa Rican and Nicaraguan rainforests, Amazon Rainforest territories of several South American countries, Madagascar dry deciduous forests ,
1140-630: The mudflats. Boleophthalmus boddarti is detritivorous , while others will eat small crabs, insects, snails and even other mudskippers. Digging deep burrows in soft sediments allows the fish to thermoregulate , avoid marine predators during the high tide when the fish and burrow are submerged, and lay their eggs. When the burrow is submerged, several mudskipper species maintain an air pocket inside it, which allows them to breathe in conditions of very low oxygen concentration. To reduce toxic ammonia production, mudskippers can suppress amino acid breakdown when exposed to air. Another method they use involves
1178-467: The partial breakdown of amino acids leading to the production of alanine, which also reduces ammonia production. Mudskippers can reduce the membrane permeability of their skin and acidify the water in their burrows to reduce levels of ammonia from the environment. Mudskippers evolved the ability to blink independently from terrestrial tetrapods . Their eyes are located high on their head compared to other gobies, and they blink by lowering their eyes as
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1216-533: The sun is still close to overhead throughout the year, therefore the tropics also have the lowest seasonal variation on the planet; "winter" and "summer" lose their contrast. Instead, seasons are more commonly divided by precipitation variations than by temperature variations. The tropics maintain wide diversity of local climates, such as rain forests , monsoons , savannahs , deserts , and high altitude snow-capped mountains . The word "tropical" can specifically refer to certain kinds of weather , rather than to
1254-420: The top of its flat head. Their most noticeable feature however is their side pectoral fins that are located more forward and under their elongated body. These fins are jointed and function similarly to limbs , which allow the mudskipper to crawl from place to place. Although having the typical body form of any other gobiid fish, these front fins allow the mudskipper to actively "skip" across muddy surfaces (hence
1292-516: The tropical and polar circles . The tropics constitute 39.8% of Earth's surface area and contain 36% of Earth's landmass . As of 2014 , the region was home also to 40% of the world's population , and this figure was then projected to reach 50% by 2050. Because of global warming , the weather conditions of the tropics are expanding with areas in the subtropics , having more extreme weather events such as heatwaves and more intense storms. These changes in weather conditions may make certain parts of
1330-469: The tropics include: Tropicality refers to the image of the tropics that people from outside the tropics have of the region, ranging from critical to verging on fetishism. Tropicality gained renewed interest in geographical discourse when French geographer Pierre Gourou published Les pays tropicaux ( The Tropical World in English), in the late 1940s. Tropicality encompassed two major images. One,
1368-568: The tropics uninhabitable. The word "tropic" comes via Latin from Ancient Greek τροπή ( tropē ), meaning "to turn" or "change direction". The tropics are defined as the region between the Tropic of Cancer in the Northern Hemisphere at 23°26′09.8″ (or 23.43605°) N and the Tropic of Capricorn in the Southern Hemisphere at 23°26′09.8″ (or 23.43605°) S; these latitudes correspond to
1406-453: The water and moving into a more dry environment on land, they are still able to breathe using water that is trapped inside their large gill chambers. They are also able to absorb oxygen from the lining of their mouth and throat, allowing them to stay out of water for long periods of time. It has been discovered that they spend up to three quarters of their life on land. They are found in tropical , subtropical , and temperate regions, including
1444-726: The wetter regime. The previous dry season leads to food shortages into the wet season, as the crops have yet to mature. However, regions within the tropics may well not have a tropical climate. Under the Köppen climate classification, much of the area within the geographical tropics is classed not as "tropical" but as "dry" ( arid or semi-arid ), including the Sahara Desert , the Atacama Desert and Australian Outback . Also, there are alpine tundra and snow-capped peaks, including Mauna Kea , Mount Kilimanjaro , Puncak Jaya and
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