Fish are gill-bearing aquatic craniate animals that lack limbs with digits. They form a sister group to the tunicates. Included in this definition are the living hagfish and cartilaginous and bony fish as well as various extinct related groups. Tetrapods emerged within lobe-finned fishes, so cladistically they are fish as well. However, traditionally fish are rendered paraphyletic by excluding the tetrapods; because in this manner the term "fish" is defined negatively as a paraphyletic group, it is not considered a formal taxonomic grouping in systematic biology, unless it is used in the cladistic sense, including tetrapods. The traditional term pisces is considered a typological, but not a phylogenetic classification; the earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. Fish would continue to evolve through the Paleozoic era.
Many fish of the Paleozoic developed external armor. The first fish with jaws appeared in the Silurian period, after which many became formidable marine predators rather than just the prey of arthropods. Most fish are ectothermic, allowing their body temperatures to vary as ambient temperatures change, though some of the large active swimmers like white shark and tuna can hold a higher core temperature. Fish can communicate in their underwater environments through the use of acoustic communication. Acoustic communication in fish involves the transmission of acoustic signals from one individual of a species to another; the production of sounds as a means of communication among fish is most used in the context of feeding, aggression or courtship behaviour. The sounds emitted by fish can vary depending on the stimulus involved, they can produce either stridulatory sounds by moving components of the skeletal system, or can produce non-stridulatory sounds by manipulating specialized organs such as the swimbladder.
Fish are abundant in most bodies of water. They can be found in nearly all aquatic environments, from high mountain streams to the abyssal and hadal depths of the deepest oceans, although no species has yet been documented in the deepest 25% of the ocean. With 33,600 described species, fish exhibit greater species diversity than any other group of vertebrates. Fish are an important resource for humans worldwide as food. Commercial and subsistence fishers hunt fish in wild fisheries or farm them in ponds or in cages in the ocean, they are caught by recreational fishers, kept as pets, raised by fishkeepers, exhibited in public aquaria. Fish have had a role in culture through the ages, serving as deities, religious symbols, as the subjects of art and movies. Fish do not represent a monophyletic group, therefore the "evolution of fish" is not studied as a single event. Early fish from the fossil record are represented by a group of small, armored fish known as ostracoderms. Jawless fish lineages are extinct.
An extant clade, the lampreys may approximate ancient pre-jawed fish. The first jaws are found in Placodermi fossils; the diversity of jawed vertebrates may indicate the evolutionary advantage of a jawed mouth. It is unclear if the advantage of a hinged jaw is greater biting force, improved respiration, or a combination of factors. Fish may have evolved from a creature similar to a coral-like sea squirt, whose larvae resemble primitive fish in important ways; the first ancestors of fish may have kept the larval form into adulthood, although the reverse is the case. Fish are a paraphyletic group: that is, any clade containing all fish contains the tetrapods, which are not fish. For this reason, groups such as the "Class Pisces" seen in older reference works are no longer used in formal classifications. Traditional classification divides fish into three extant classes, with extinct forms sometimes classified within the tree, sometimes as their own classes: Class Agnatha Subclass Cyclostomata Subclass Ostracodermi † Class Chondrichthyes Subclass Elasmobranchii Subclass Holocephali Class Placodermi † Class Acanthodii † Class Osteichthyes Subclass Actinopterygii Subclass Sarcopterygii The above scheme is the one most encountered in non-specialist and general works.
Many of the above groups are paraphyletic, in that they have given rise to successive groups: Agnathans are ancestral to Chondrichthyes, who again have given rise to Acanthodiians, the ancestors of Osteichthyes. With the arrival of phylogenetic nomenclature, the fishes has been split up into a more detailed scheme, with the following major groups: Class Myxini Class Pteraspidomorphi † Class Thelodonti † Class Anaspida † Class Petromyzontida or Hyperoartia Petromyzontidae Class Conodonta † Class Cephalaspidomorphi † Galeaspida † Pituriaspida † Osteostraci † Infraphylum Gnathostomata Class Placodermi † Class Chondrichthyes Class Acanthodii † Superclass Osteichthy
The danionins are a group of small minnow-type fish belonging to the family Cyprinidae. Members of this group are in the genera Danio and Rasbora, they are native to the fresh waters of South and Southeast Asia, with fewer species in Africa. Many species are available as aquarium fish worldwide. Danio species tend to have horizontal stripes, rows of spots, or vertical bars, have long barbels. Devario species tend to have vertical or horizontal bars, short rudimentary barbels, if barbels are present at all. All danionins are egg scatterers and breed in the rainy season in the wild, they are carnivores living on small crustaceans. The grouping of fish now deemed danionins has been the subject of constant research and speculation throughout the 20th century. Nearly all the fish classed within the genera Danio and Devario were placed in the genus Danio upon discovery. However, in the first part of the 20th century, George S. Myers split them into three genera, Danio and Daniops; the sole species within Myers' Daniops, D. myersi, has long ago been found to be a synonym of Devario laoensis, but his genus Brachydanio lasted for much longer, as it included most of the fish now classed as Danio, whereas Danio included most of the fish now classed as Devario.
However, Danio dangila and Danio feegradei, both of which had most of the characteristics of the Brachydanio were placed within Danios.. In 1941, H. M. Smith attempted to unite all the Brachydanios and Danios species into one genus on the basis of a fish from Thailand, supposed to bridge the gap, he downgraded both Danio and Brachydanio into subgenera and erected a new subgenus of Allodanio with one member, Allodanio ponticulus, but Myers pointed out that A. ponticulus was a member of the genus Barilius. The danionin group was thought to include Parabarilius, Danio and Danionella. In this scheme, danionins were distinguished from other cyprinids by the uniquely shared character of the "danionin notch", a large and peculiarly shaped indentation in the medial margin of the mandibles. However, all of these categories at that time were informal. Microrasbora was not considered to be a part of the danionins, nor closely related to Danionella, a part of the danionins as understood at that time. In the late 1980s and 1990s, doubts grew about the validity of Brachydanio, with species being referred to their original naming of Danio, Fang Fang determined that the genus Danio, recognized up to that point, was paraphyletic.
Fang restricted Danio to the species in the "D. dangila species group", which at the time comprised nine species including D. dangila, D. rerio, D. nigrofasciatus, D. albolineatus. The only Danio species to have been called Danio were D. dangila and D. feegradei. As D. dangila was the first discovered Danio the name Danio had to remain with D. dangila, why the vast majority of species were moved to Devario. The sister group to Devario was deemed to be a clade formed by Inlecypris and Chela, more controversially, Esomus was found to be the sister group of Danio; the relationships of Sundadanio and Microrasbora remained unresolved. The danionin notch was found to not supported to be a danionin synapomorphy. In another paper, Celestichthys margaritatus was described as a new species of the Danioninae, it is most related to Microrasbora erythromicron. The genus is identified as a danionin due specializations of its lower jaw and its numerous anal fin rays. Though it lacks a danionin notch, Celestichthys exhibits the "danionin mandibular knob", a bony process on the side of the mandible behind the danionin notch or where the notch should be.
This knob is better developed in males than females. The fish of Rasborinae invariably have anal fins with three spines and five rays. Celestichthys has 8-10 anal fin rays. Rasborins have the generalized cyprinid principal caudal fin ray count of 10/9, while all Asian cyprinids with fewer than 10/9 principal caudal fin rays are all diminutive species of Danioninae, including Celestichthys, M. erythromicron and Paedocypris. In 2007, an analysis of the phylogenetic relationships of the described genus Paedocypris was published, placing it as the sister taxon to Sundadanio; the clade formed by these two genera was found to be sister to a clade including many danionin genera, as well as some rasborin genera such as Rasbora and Boraras, making the danionin group paraphyletic without these rasborin genera based on these results. This paper considered the danionin genera to be within a larger Rasborinae. In 2007, another study analyzed the relationships of Danio; these authors considered Rasborinae to have priority over Danioninae, suggesting that they have the same meaning.
Danio was found to be the sister group of a clade including Chela, Microrasbora and Inlecypris, rather than in a clade with either Devario or Esomus as in previous studies. This paper supported the close relationship of "Microrasbora" erythromicron to Danio species.
International Union for Conservation of Nature
The International Union for Conservation of Nature is an international organization working in the field of nature conservation and sustainable use of natural resources. It is involved in data gathering and analysis, field projects and education. IUCN's mission is to "influence and assist societies throughout the world to conserve nature and to ensure that any use of natural resources is equitable and ecologically sustainable". Over the past decades, IUCN has widened its focus beyond conservation ecology and now incorporates issues related to sustainable development in its projects. Unlike many other international environmental organisations, IUCN does not itself aim to mobilize the public in support of nature conservation, it tries to influence the actions of governments and other stakeholders by providing information and advice, through building partnerships. The organization is best known to the wider public for compiling and publishing the IUCN Red List of Threatened Species, which assesses the conservation status of species worldwide.
IUCN has a membership of over 1400 non-governmental organizations. Some 16,000 scientists and experts participate in the work of IUCN commissions on a voluntary basis, it employs 1000 full-time staff in more than 50 countries. Its headquarters are in Switzerland. IUCN has observer and consultative status at the United Nations, plays a role in the implementation of several international conventions on nature conservation and biodiversity, it was involved in establishing the World Wide Fund for Nature and the World Conservation Monitoring Centre. In the past, IUCN has been criticized for placing the interests of nature over those of indigenous peoples. In recent years, its closer relations with the business sector have caused controversy. IUCN was established in 1948, it was called the International Union for the Protection of Nature and the World Conservation Union. Establishment IUCN was established on 5 October 1948, in Fontainebleau, when representatives of governments and conservation organizations signed a formal act constituting the International Union for the Protection of Nature.
The initiative to set up the new organisation came from UNESCO and from its first Director General, the British biologist Julian Huxley. The objectives of the new Union were to encourage international cooperation in the protection of nature, to promote national and international action and to compile and distribute information. At the time of its founding IUPN was the only international organisation focusing on the entire spectrum of nature conservation Early years: 1948–1956 IUPN started out with 65 members, its secretariat was located in Brussels. Its first work program focused on saving species and habitats and applying knowledge, advancing education, promoting international agreements and promoting conservation. Providing a solid scientific base for conservation action was the heart of all activities. IUPN and UNESCO were associated, they jointly organized the 1949 Conference on Protection of Nature. In preparation for this conference a list of gravely endangered species was drawn up for the first time, a precursor of the IUCN Red List of Threatened Species.
In the early years of its existence IUCN depended entirely on UNESCO funding and was forced to temporarily scale down activities when this ended unexpectedly in 1954. IUPN was successful in engaging prominent scientists and identifying important issues such as the harmful effects of pesticides on wildlife but not many of the ideas it developed were turned into action; this was caused by unwillingness to act on the part of governments, uncertainty about the IUPN mandate and lack of resources. In 1956, IUPN changed its name to International Union for Conservation of Nature and Natural Resources. Increased profile and recognition: 1956–1965 In the 1950s and 1960s Europe entered a period of economic growth and formal colonies became independent. Both developments had impact on the work of IUCN. Through the voluntary involvement of experts in its Commissions IUCN was able to get a lot of work done while still operating on a low budget, it established links with the Council of Europe. In 1961, at the request of United Nations Economic and Social Council, the United Nations Economic and Social Council, IUCN published the first global list of national parks and protected areas which it has updated since.
IUCN's best known publication, the Red Data Book on the conservation status of species, was first published in 1964. IUCN began to play a part in the development of international treaties and conventions, starting with the African Convention on the Conservation of Nature and Natural Resources. Environmental law and policy making became a new area of expertise. Africa was the focus of many of the early IUCN conservation field projects. IUCN supported the ‘Yellowstone model’ of protected area management, which restricted human presence and activity in order to protect nature. IUCN and other conservation organisations were criticized for protecting nature against people rather than with people; this model was also applied in Africa and played a role in the decision to remove the Maasai people from Serengeti National Park and the Ngorongoro Conservation Area. To establish a stable financial basis for its work, IUCN participated in setting up the World Wildlife Fund
The Cyprinidae are the family of freshwater fishes, collectively called cyprinids, that includes the carps, the true minnows, their relatives. Called the "carp family", or "minnow family", Cyprinidae is the largest and most diverse fish family and the largest vertebrate animal family in general, with about 3,000 species of which only 1,270 remain extant, divided into about 370 genera.. They range from about 12 mm to the 3-meter Catlocarpio siamensis; this family of fish is one of the few. The family belongs to the ostariophysian order Cypriniformes, of whose genera and species the cyprinids make more than two-thirds; the family name is derived from the Ancient Greek kyprînos. Cyprinids are stomachless fish with toothless jaws. So, food can be chewed by the gill rakers of the specialized last gill bow; these pharyngeal teeth allow the fish to make chewing motions against a chewing plate formed by a bony process of the skull. The pharyngeal teeth are used by scientists to identify species. Strong pharyngeal teeth allow fish such as the common carp and ide to eat hard baits such as snails and bivalves.
Hearing is a well-developed sense in the cyprinids since they have the Weberian organ, three specialized vertebral processes that transfer motion of the gas bladder to the inner ear. The vertebral processes of the Weberian organ permit a cyprinid to detect changes in motion of the gas bladder due to atmospheric conditions or depth changes; the cyprinids are considered physostomes because the pneumatic duct is retained in adult stages and the fish are able to gulp air to fill the gas bladder, or they can dispose excess gas to the gut. Cyprinids are native to North America and Eurasia; the largest known cyprinid is the giant barb, which may grow up to 3 m in length and 300 kg in weight. Other large species that can surpass 2 m are the golden mahseer and mangar; the largest North American species is the Colorado pikeminnow, which can reach up to 1.8 m in length. Conversely, many species are smaller than 5 cm; the smallest known fish is Paedocypris progenetica, reaching 10.3 mm at the longest. All fish in this family most do not guard their eggs.
The bitterlings of subfamily Acheilognathinae are notable for depositing their eggs in bivalve molluscs, where the young develop until able to fend for themselves. Most cyprinids feed on invertebrates and vegetation due to the lack of teeth and stomach. Many species, such as the ide and the common rudd, prey on small fish when individuals become large enough. Small species, such as the moderlieschen, are opportunistic predators that will eat larvae of the common frog in artificial circumstances; some cyprinids, such as the grass carp, are specialized herbivores. For this reason, cyprinids are introduced as a management tool to control various factors in the aquatic environment, such as aquatic vegetation and diseases transmitted by snails. Unlike most fish species, cyprinids increase in abundance in eutrophic lakes. Here, they contribute towards positive feedback as they are efficient at eating the zooplankton that would otherwise graze on the algae, reducing its abundance. Cyprinids are important food fish.
In land-locked countries in particular, cyprinids are the major species of fish eaten because they make the largest part of biomass in most water types except for fast-flowing rivers. In Eastern Europe, they are prepared with traditional methods such as drying and salting; the prevalence of inexpensive frozen fish products made this less important now than it was in earlier times. Nonetheless, in certain places, they remain popular for food, as well as recreational fishing, have been deliberately stocked in ponds and lakes for centuries for this reason. Cyprinids are popular for angling for match fishing and fishing for common carp because of its size and strength. Several cyprinids have been introduced to waters outside their natural ranges to provide food, sport, or biological control for some pest species; the common carp and the grass carp are the most important for example in Florida. In some cases, such as the Asian carp in the Mississippi Basin, they have become invasive species that compete with native fishes or disrupt the environment.
Carp in particular can stir up sediment, reducing the clarity of the water and making it difficult for plants to grow. Numerous cyprinids have become important in the aquarium and fishpond hobbies, most famously the goldfish, bred in China from the Prussian carp. First imported into Europe around 1728, it was much fancied by Chinese nobility as early as 1150 AD and after it arrived there in 1502 in Japan. In the latter country, from the 18th century onwards, the common carp was bred into the ornamental variety known as koi – or more nishikigoi, as koi means "common carp" in Japanese. Other popular aquarium cyprinids include danionins and true barbs. Larger species are bred by the thousands in outdoor ponds in Southeast Asia, trade in these aquarium fishes
Actinopterygii, or the ray-finned fishes, constitute a class or subclass of the bony fishes. The ray-finned fishes are so called because their fins are webs of skin supported by bony or horny spines, as opposed to the fleshy, lobed fins that characterize the class Sarcopterygii; these actinopterygian fin rays attach directly to the proximal or basal skeletal elements, the radials, which represent the link or connection between these fins and the internal skeleton. Numerically, actinopterygians are the dominant class of vertebrates, comprising nearly 99% of the over 30,000 species of fish, they are ubiquitous throughout freshwater and marine environments from the deep sea to the highest mountain streams. Extant species can range in size from Paedocypris, at 8 mm, to the massive ocean sunfish, at 2,300 kg, the long-bodied oarfish, at 11 m. Ray-finned fishes occur in many variant forms; the main features of a typical ray-finned fish are shown in the adjacent diagram. In nearly all ray-finned fish, the sexes are separate, in most species the females spawn eggs that are fertilized externally with the male inseminating the eggs after they are laid.
Development proceeds with a free-swimming larval stage. However other patterns of ontogeny exist, with one of the commonest being sequential hermaphroditism. In most cases this involves protogyny, fish starting life as females and converting to males at some stage, triggered by some internal or external factor. Protandry, where a fish converts from male to female, is much less common than protogyny. Most families use external rather than internal fertilization. Of the oviparous teleosts, most do not provide parental care. Viviparity, ovoviviparity, or some form of parental care for eggs, whether by the male, the female, or both parents is seen in a significant fraction of the 422 teleost families. Viviparity is rare and is found in about 6% of teleost species. Male territoriality "preadapts" a species for evolving male parental care. There are a few examples of fish; the mangrove rivulus is an amphibious, simultaneous hermaphrodite, producing both eggs and spawn and having internal fertilisation.
This mode of reproduction may be related to the fish's habit of spending long periods out of water in the mangrove forests it inhabits. Males are produced at temperatures below 19 °C and can fertilise eggs that are spawned by the female; this maintains genetic variability in a species, otherwise inbred. The earliest known fossil actinopterygiian is Andreolepis hedei. Remains have been found in Russia and Estonia. Actinopterygians are divided into the subclasses Neopterygii; the Neopterygii, in turn, are divided into the infraclasses Teleostei. During the Mesozoic and Cenozoic the teleosts in particular diversified and as a result, 96% of all known fish species are teleosts; the cladogram shows the major groups of actinopterygians and their relationship to the terrestrial vertebrates that evolved from a related group of fish. Approximate dates are from al.. 2012. The polypterids are the sister lineage of all other actinopterygians, the Acipenseriformes are the sister lineage of Neopterygii, Holostei are the sister lineage of teleosts.
The Elopomorpha appears to be the most basic teleosts. The listing below follows Phylogenetic Classification of Bony Fishes with notes when this differs from Nelson, ITIS and FishBase and extinct groups from Van der Laan 2016. Order †? Asarotiformes Schaeffer 1968 Order †? Discordichthyiformes Minikh 1998 Order †? Paphosisciformes Grogan & Lund 2015 Order †? Scanilepiformes Selezneya 1985 Order †Cheirolepidiformes Kazantseva-Selezneva 1977 Order †Paramblypteriformes Heyler 1969 Order †Rhadinichthyiformes Order †Palaeonisciformes Hay 1902 Order †Tarrasiiformes sensu Lund & Poplin 2002 Order †Ptycholepiformes Andrews et al. 1967 Order †Redfieldiiformes Berg 1940 Order †Haplolepidiformes Westoll 1944 Order †Aeduelliformes Heyler 1969 Order †Platysomiformes Aldinger 1937 Order †Dorypteriformes Cope 1871 Order †Eurynotiformes Sallan & Coates 2013 Subclass Cladistii Pander 1860 Order †Guildayichthyiformes Lund 2000 Order Polypteriformes Bleeker 1859 Clade Actinopteri Cope 1972 s.s. Order †Elonichthyiformes Kazantseva-Selezneva 1977 Order †Phanerorhynchiformes Order †Saurichthyiformes Berg 1937 Subclass Chondrostei Order †Birgeriiformes Jin 2001 Order †Chondrosteiformes Order Acipenseriformes Berg 1940 Subclass Neopterygii Regan 1923 sensu Xu & Wu 2012 Order †Pholidopleuriformes Berg 1937 Order †Peltopleuriformes Lehman 1966 Order †Perleidiformes Berg 1937 Order †Luganoiiformes Lehman 1958 Order †Pycnodontiformes Berg 1937 Infraclass Holostei Muller 1844 Division Halecomorpha Cope 1872 sensu Grande & Bemis 1998 Order †Parasemionotiformes Lehman 1966 Order †Ionoscopiformes Grande & Bemis 1998 Order Amiiformes Huxley 1861 sensu Grande & Bemis 1998 Division Ginglymodi Cope 1871 Order †Dapediiformes Thies & Waschkewitz 2015 Order †Semionotiformes Arambourg & Bertin 1958 Order Lepisosteiformes Hay 1929 Clade Teleosteomorpha Arratia 2000 sensu Arratia 2013 Order †Prohaleciteiformes Arratia 2017 Division Aspidorhynchei Nelson, Grand & Wilson 2016 Order †Aspidorhynchiformes Bleeker 1859 Order †Pachycormiformes Berg 1937 Infraclass Teleostei Müller 1844 sensu Arratia 2013 Order †?
Araripichthyiformes Order †? Ligulelliiformes Taverne 2011 Order †? Tselfatiiformes Nelson 1994 Order †Pholidophori
Devario is a genus of fish in the family Cyprinidae native to the rivers and streams of South and Southeast Asia. These fishes have many species having vertical or horizontal stripes; these species consume various small, aquatic insects and worms, as well as, in the case of fry, plankton. 43 species in this genus are recognized
Terrestrial animals are animals that live predominantly or on land, as compared with aquatic animals, which live predominantly or in the water, or amphibians, which rely on a combination of aquatic and terrestrial habitats. Terrestrial invertebrates include ants, crickets and spiders; the term terrestrial is applied for species that live on the ground, in contrast to arboreal species, which live in trees. There are other less common terms that apply to specific groups of terrestrial animals: Saxicolous creatures are rock dwelling. Saxicolous is derived from the Latin word "saxum," meaning a rock. Arenicolous creatures live in the sand. Troglofauna predominantly live in caves. Terrestrial invasion is one of the most important events in the history of life. Terrestrial lineages evolved in several animal phyla, among which vertebrates and mollusks are representatives of more successful groups of terrestrial animals. Terrestrial animals do not form a unified clade; the transition from an aquatic to terrestrial life has evolved independently and many times by various groups of animals.
Most terrestrial lineages originated under a mild or tropical climate during the Paleozoic and Mesozoic, whereas few animals became terrestrial during the Cenozoic. When excluding internal parasites, free living species in terrestrial environments are represented by the following ten phyla: flatworms, nematodes, tardigrades, arthropods, mollusks and chordates. Roundworms and rotifers are microscopic animals that require a film of water to live in, are not considered terrestrial. Flatworms, ribbon worms, velvet worms and annelids all depend on more or less moist habitats, as do the arthropods centipedes and millipedes; the three remaining phyla, arthropods and chordates, all contain species that have adapted to dry terrestrial environments, contain species that have no aquatic phase in their life cycles. Labeling an animal species "terrestrial" or "aquatic" is obscure and becomes a matter of judgment. Many animals considered terrestrial have a life-cycle, dependent on being in water. Penguins and walruses sleep on land and feed in the ocean, yet they are all considered terrestrial.
Many insects, e.g. mosquitos, all terrestrial crabs, as well as other clades, have an aquatic life cycle stage: their eggs need to be laid in and to hatch in water. There are crab species that are aquatic, crab species that are amphibious, crab species that are terrestrial. Fiddler crabs are called "semi-terrestrial" since they make burrows in the muddy substrate, to which they retreat during high tides; when the tide is out, fiddler crabs search the beach for food. The same is true in the mollusca. Many hundreds of gastropod genera and species live in intermediate situations, such as for example, Truncatella; some gastropods with gills live on land, others with a lung live in the water. As well as the purely terrestrial and the purely aquatic animals, there are many borderline species. There are no universally accepted criteria for deciding how to label these species, thus some assignments are disputed. Fossil evidence has shown that sea creatures related to arthropods, first began to make forays on to land around 530 million years ago.
There is little reason to believe, that animals first began living reliably on land around this same time period. A more hypothesis is that these early arthropods' motivation for venturing on to dry land was to mate or lay eggs out of the reach of predators; as time went on, evidence suggests that by 375 million years ago the bony fish best adapted to life in shallow coastal/swampy waters, were much more viable as amphibians than were their arthropod predecessors. Thanks to strong, muscular limbs, lungs which existed in conjunction with gills and animals like it were able to establish a strong foothold on land by the end of the Devonian period; as such, they are the most recent common ancestor of all modern tetrapods. Gastropod mollusks are one of the most successful animals that have diversified in the terrestrial habitat, they have evolved terrestrial taxa in more than nine lineages. They are referred to as land snails and slugs. Terrestrial invasion of gastropod mollusks has occurred in Neritopsina, Littorinoidea, Ellobioidea, Veronicelloidea and Stylommatophora, in particular, each of Neritopsina and Ellobioidea has achieved land invasion more than once.
Most terrestrialization events have occurred during the Mesozoic. Gastropods are unique due to several terrestrial and epifaunal lineages that evolved during the Cenozoic; some members of rissooidean families Truncatellidae and Pomatiopsidae are considered to have colonized to land during the Cenozoic. Most truncatellid and assimineid snails amphibiously live in intertidal and supratidal zones from brackish water to pelagic areas. Terrestrial lineages evolved from such ancestors; the rissooidean gastropod family Pomatiopsidae is one of the few groups that have evolved terrestrial