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Ascaphus
The tailed frogs are two species of frogs in the genus ''Ascaphus'', the only taxon in the family Ascaphidae . The "tail" in the name is actually an extension of the male cloaca. The tail is one of two distinctive anatomical features adapting the species to life in fast-flowing streams. These are the only North American frog species that reproduce by internal fertilization. They are among the most primitive known families of frogs. Its scientific name means 'without a spade', from the privative prefix '' a-'' and the Ancient Greek ' (, 'spade, shovel'), referring to the metatarsal spade, which these frogs do not have. Taxonomy Until 2001, the genus was believed to be monotypic, the single species being the tailed frog (''Ascaphus truei'' Stejneger, 1899). However, in that year, Nielson, Lohman, and Sullivan published evidence that promoted the Rocky Mountain tailed frog (''Ascaphus montanus'') from a subspecies to its own species. Since then, the former species has been formall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ascaphus Montanus Tadpole
The tailed frogs are two species of frogs in the genus ''Ascaphus'', the only taxon in the family Ascaphidae . The "tail" in the name is actually an extension of the male cloaca. The tail is one of two distinctive anatomical features adapting the species to life in fast-flowing streams. These are the only North American frog species that reproduce by internal fertilization. They are among the most primitive known families of frogs. Its scientific name means 'without a spade', from the privative prefix '' a-'' and the Ancient Greek ' (, 'spade, shovel'), referring to the metatarsal spade, which these frogs do not have. Taxonomy Until 2001, the genus was believed to be monotypic, the single species being the tailed frog (''Ascaphus truei'' Stejneger, 1899). However, in that year, Nielson, Lohman, and Sullivan published evidence that promoted the Rocky Mountain tailed frog (''Ascaphus montanus'') from a subspecies to its own species. Since then, the former species has been formally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tailed Frog
The tailed frogs are two species of frogs in the genus ''Ascaphus'', the only taxon in the family Ascaphidae . The "tail" in the name is actually an extension of the male cloaca. The tail is one of two distinctive anatomical features adapting the species to life in fast-flowing streams. These are the only North American frog species that reproduce by internal fertilization. They are among the most primitive known families of frogs. Its scientific name means 'without a spade', from the privative prefix '' a-'' and the Ancient Greek ' (, 'spade, shovel'), referring to the metatarsal spade, which these frogs do not have. Taxonomy Until 2001, the genus was believed to be monotypic, the single species being the tailed frog (''Ascaphus truei'' Stejneger, 1899). However, in that year, Nielson, Lohman, and Sullivan published evidence that promoted the Rocky Mountain tailed frog (''Ascaphus montanus'') from a subspecies to its own species. Since then, the former species has been formall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frog
A frog is any member of a diverse and largely Carnivore, carnivorous group of short-bodied, tailless amphibians composing the order (biology), order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is known from the Early Triassic of Madagascar, but molecular clock, molecular clock dating suggests their split from other amphibians may extend further back to the Permian, 265 Myr, million years ago. Frogs are widely distributed, ranging from the tropics to subarctic regions, but the greatest concentration of species diversity is in tropical rainforest. Frogs account for around 88% of extant amphibian species. They are also one of the five most diverse vertebrate orders. Warty frog species tend to be called toads, but the distinction between frogs and toads is informal, not from Taxonomy (biology), taxonomy or evolutionary history. An adult frog has a stout body, protruding eyes, anteriorly-attached tongue, limb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tadpole
A tadpole is the larval stage in the biological life cycle of an amphibian. Most tadpoles are fully aquatic, though some species of amphibians have tadpoles that are terrestrial. Tadpoles have some fish-like features that may not be found in adult amphibians such as a lateral line, gills and swimming tails. As they undergo metamorphosis, they start to develop functional lungs for breathing air, and the diet of tadpoles changes drastically. A few amphibians, such as some members of the frog family Brevicipitidae, undergo direct development i.e., they do not undergo a free-living larval stage as tadpoles instead emerging from eggs as fully formed "froglet" miniatures of the adult morphology. Some other species hatch into tadpoles underneath the skin of the female adult or are kept in a pouch until after metamorphosis. Having no hard skeletons, it might be expected that tadpole fossils would not exist. However, traces of biofilms have been preserved and fossil tadpoles have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leiopelmatidae
__NOTOC__ ''Leiopelma'' is a genus of New Zealand primitive frogs, belonging to the suborder Archaeobatrachia. It is the only genus in the monotypic family Leiopelmatidae. The leiopelmatids' relatively basal form indicates they have an ancient lineage. While some taxonomists have suggested combining the North American frogs of the genus ''Ascaphus'' in the family Ascaphidae with the New Zealand frogs of the genus ''Leiopelma'' in the family Leiopelmatidae, the current consensus is that these two groups constitute two separate families. The four extant species of Leiopelmatidae are only found in New Zealand. Overview The New Zealand primitive frogs' defining characteristics are their extra vertebrae (for a total of nine) and the remains of the tail muscles (the tail itself is absent in adults, although it is present in the younger frogs, which need the extra skin surface until their lungs are fully developed). The family Ascaphidae (found only in North America), of the same suborde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leonhard Hess Stejneger
Leonhard Hess Stejneger (30 October 1851 – 28 February 1943) was a Norwegian-born American ornithologist, herpetologist and zoologist. Stejneger specialized in vertebrate natural history studies. He gained his greatest reputation with reptiles and amphibians. Wetmore, Alexander (1945). "Leonhard Hess Stejneger (1851-1943)". ''Biographical Memoir. Nat. Acad. Sci.'' 24: 145-195PDF/ref> Early life and family Stejneger was born in Bergen, Norway. His father was Peter Stamer Steineger, a merchant and auditor; his mother was Ingeborg Catharine (née Hess). Leonhard was the eldest of seven children. His sister Agnes Steineger was a Norwegian artist. Until 1880, the Steineger family had been one of the wealthy families in Bergen; at that time business reverses led to the father declaring bankruptcy. Stejneger attended the Smith Theological School in Bergen from 1859 to 1860, and Bergen Latin School until 1869. His interests in zoology developed early. By age sixteen he had a pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The larva's appearance is generally very different from the adult form (''e.g.'' caterpillars and butterflies) including different unique structures and organs that do not occur in the adult form. Their diet may also be considerably different. Larvae are frequently adapted to different environments than adults. For example, some larvae such as tadpoles live almost exclusively in aquatic environments, but can live outside water as adult frogs. By living in a distinct environment, larvae may be given shelter from predators and reduce competition for resources with the adult population. Animals in the larval stage will consume food to fuel their transition into the adult form. In some organisms like polychaetes and barnacles, adults are immobil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vieraella
''Vieraella'' is an extinct genus of frog from the Lower Jurassic (Early Pliensbachian to Toarcian) Roca Blanca Formation of Argentina, and one of the oldest true frogs known. This genus is known by a single excepcionally well preserved specimen, P.V.L. 2188, with at least eight presacrals vertebrae, free ribs, ulna and radius not fused, bony skull with some discoglossid characters. Description Despite living around 188 million years ago, ''Vieraella'' was anatomically very similar to modern frogs. For example, its hind legs were adapted for jumping, and the skull already possessed the lattice-like form found in modern species. It was, however, an unusually small frog, measuring only in length. Although older frog-like creatures are known, such as ''Triadobatrachus ''Triadobatrachus'' is an extinct genus of salientian frog-like amphibians, including only one known species, ''Triadobatrachus massinoti''. It is the oldest member of the frog lineage known, and an excellent e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breeding Season
Seasonal breeders are animal species that successfully mate only during certain times of the year. These times of year allow for the optimization of survival of young due to factors such as ambient temperature, food and water availability, and changes in the predation behaviors of other species. Related sexual interest and behaviors are expressed and accepted only during this period. Female seasonal breeders will have one or more estrus cycles only when she is "in season" or fertile and receptive to mating. At other times of the year, they will be anestrus, or have a dearth of their sexual cycle. Unlike reproductive cyclicity, seasonality is described in both males and females. Male seasonal breeders may exhibit changes in testosterone levels, testes weight, and fertility depending on the time of year. Seasonal breeders are distinct from opportunistic breeders, that mate whenever the conditions of their environment become favorable, and continuous breeders that mate year-round. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Egg (biology)
An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the animal hatches. Most arthropods such as insects, vertebrates (excluding live-bearing mammals), and mollusks lay eggs, although some, such as scorpions, do not. Reptile eggs, bird eggs, and monotreme eggs are laid out of water and are surrounded by a protective shell, either flexible or inflexible. Eggs laid on land or in nests are usually kept within a warm and favorable temperature range while the embryo grows. When the embryo is adequately developed it hatches, i.e., breaks out of the egg's shell. Some embryos have a temporary egg tooth they use to crack, pip, or break the eggshell or covering. The largest recorded egg is from a whale shark and was in size. Whale shark eggs typically hatch within the mother. At and up to , the o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae. Their blood is not totally contained in vessels; some circulates in an open cavity known as the haemocoel. Insects are the most diverse group of animals; they include more than a million described species and represent more than half of all known living organisms. The total number of extant species is estimated at between six and ten million; In: potentially over 90% of the animal life forms on Earth are insects. Insects may be found in nearly all environments, although only a small number of species reside in the oceans, which are dominated by another arthropod group, crustaceans, which recent research has indicated insects are nested within. Nearly all insects hatch from eggs. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philopatry
Philopatry is the tendency of an organism to stay in or habitually return to a particular area. The causes of philopatry are numerous, but natal philopatry, where animals return to their birthplace to breed, may be the most common. The term derives from the Greek roots ''philo'', "liking, loving" and ''patra'', "fatherland", although in recent years the term has been applied to more than just the animal's birthplace. Recent usage refers to animals returning to the same area to breed despite not being born there, and migratory species that demonstrate site fidelity: reusing stopovers, staging points, and wintering grounds. Some of the known reasons for organisms to be philopatric would be for mating (reproduction), survival, migration, parental care, resources, etc.. In most species of animals, individuals will benefit from living in groups, because depending on the species, individuals are more vulnerable to predation and more likely to have difficulty finding resources and food. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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