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Pauropods
Pauropods are small, pale, millipede-like arthropods. Around 830 species in twelve families are found worldwide, living in soil and leaf mold. They look rather like centipedes, or millipedes, and may be a sister group of the latter. However, this is controversial, as a close relationship with Symphyla has also been posited. Anatomy and ecology Pauropods are soft, cylindrical animals with bodies long. They have neither eyes nor hearts, although they do have sensory organs which can detect light. The body segments have ventral tracheal/spiracular pouches forming apodemes similar to those in millipedes and Symphyla, although the trachea usually connected to these structures are absent in most species. There are long sensory hairs located throughout the body segments. Pauropods can usually be identified because of their distinctive anal plate, which is unique to pauropods. Different species of pauropods can be identified based on the size and shape of their anal plate. The antenn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Millipede
Millipedes are a group of arthropods that are characterised by having two pairs of jointed legs on most body segments; they are known scientifically as the class Diplopoda, the name derived from this feature. Each double-legged segment is a result of two single segments fused together. Most millipedes have very elongated cylindrical or flattened bodies with more than 20 segments, while pill millipedes are shorter and can roll into a tight ball. Although the name "millipede" derives from the Latin for "thousand feet", no species was known to have 1,000 or more until the discovery of ''Eumillipes persephone'', which can have over 1,300 legs. There are approximately 12,000 named species classified into 16 orders and around 140 families, making Diplopoda the largest class of myriapods, an arthropod group which also includes centipedes and other multi-legged creatures. Most millipedes are slow-moving detritivores, eating decaying leaves and other dead plant matter. Some eat fungi or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eurypauropod
Eurypauropodidae is a family of pauropods. The family was first described by the American zoologist John A. Ryder during October 1873. Eurypauropodids are generally less than 1 millimeter long, and their outer plates are usually completely sclerotised Sclerotin is a component of the cuticle of various Arthropoda, most familiarly insects. It is formed by cross-linking members of particular classes of protein molecules, a biochemical process called sclerotization, a form of tanning in which qui .... References External links * Myriapod families {{Myriapoda-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetramerocerata
Tetramerocerata is an order of pauropods containing 12 different families and about 480 different species. Tetrameroceratans have a 12 segmented body, 4 segmented antennae, 6 tergites, and 8 to10 legs pairs of legs as adults. Most pauropods in this order have 9 leg pairs as adults, but four genera (''Cauvetauropus'', ''Aletopauropus'', ''Zygopauropus'', and ''Amphipauropus'') have only 8 pairs, and adult females in the genus ''Decapauropus'' (in the Pauropodidae Pauropodidae is a family of pauropods. It contains over 20 genera and 650 species, as well as the only known fossil pauropod, '' Eopauropus''. Like most adult pauropods in the order Tetramerocerata Tetramerocerata is an order Order, ORDER or ... family) have either nine or ten pairs of legs. Pauropods in this order are generally 0.5 mm to 2 mm long, and are usually white or brown. Tetramerocerata has a subcosmopolitan distribution, occurring nearly worldwide. References External links * Myriapod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Millipede
Millipedes are a group of arthropods that are characterised by having two pairs of jointed legs on most body segments; they are known scientifically as the class Diplopoda, the name derived from this feature. Each double-legged segment is a result of two single segments fused together. Most millipedes have very elongated cylindrical or flattened bodies with more than 20 segments, while pill millipedes are shorter and can roll into a tight ball. Although the name "millipede" derives from the Latin for "thousand feet", no species was known to have 1,000 or more until the discovery of ''Eumillipes persephone'', which can have over 1,300 legs. There are approximately 12,000 named species classified into 16 orders and around 140 families, making Diplopoda the largest class of myriapods, an arthropod group which also includes centipedes and other multi-legged creatures. Most millipedes are slow-moving detritivores, eating decaying leaves and other dead plant matter. Some eat fungi or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene
The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "dawn") and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isotope Carbon-13, 13C in the atmosphere was exceptionally low in comparison with the more common isotope Carbon-12, 12C. The end is set at a major extinction event called the ''Grande Coupure'' (the "Great Break" in continuity) or the Eocene–Oligocene extinction event, which may be related to the impact of one or more large bolides in Popigai impact structure, Siberia and in what is now ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centipede
Centipedes (from New Latin , "hundred", and Latin , " foot") are predatory arthropods belonging to the class Chilopoda (Ancient Greek , ''kheilos'', lip, and New Latin suffix , "foot", describing the forcipules) of the subphylum Myriapoda, an arthropod group which includes millipedes and other multi-legged animals. Centipedes are elongated segmented (metameric) creatures with one pair of legs per body segment. All centipedes are venomous and can inflict painful bites, injecting their venom through pincer-like appendages known as forcipules. Despite the name, centipedes can have a varying number of legs, ranging from 30 to 382. Centipedes always have an odd number of pairs of legs; no centipede has exactly 100. Like spiders and scorpions, centipedes are predominantly carnivorous. Their size ranges from a few millimetres in the smaller lithobiomorphs and geophilomorphs to about in the largest scolopendromorphs. Centipedes can be found in a wide variety of environments. They ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpheus Spring Packard
Alpheus Spring Packard Jr. LL.D. (February 19, 1839 – February 14, 1905) was an American entomologist and palaeontologist. He described over 500 new animal species – especially butterflies and moths – and was one of the founders of ''The American Naturalist''.Cockerell (1920) Early life He was the son of Alpheus Spring Packard Sr. (1798–1884) and the brother of William Alfred Packard. He was born in Brunswick, Maine, and was Professor of Zoology and Geology at Brown University in Providence, Rhode Island, from 1878 until his death. He was a vocal proponent of Neo-Lamarckism during the eclipse of Darwinism.Sorenson (1995) Career & Works His chief work was the classification and anatomy of arthropods, and contributions to economic entomology, zoogeography, and the phylogeny and metamorphoses of insects. Packard was appointed to the United States Entomological Commission in 1877 where he served with Charles Valentine Riley and Cyrus Thomas.Mallis (1971) He wrote school text ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gonochorism
In biology, gonochorism is a sexual system where there are only two Sex, sexes and each individual organism is either male or female. The term gonochorism is usually applied in animal species, the vast majority of which are gonochoric. Gonochorism contrasts with Hermaphrodite, simultaneous hermaphroditism but it may be hard to tell if a species is gonochoric or sequentially hermaphroditic. (e.g. Parrotfish, ''Patella ferruginea''). However, in gonochoric species individuals remain either male or female throughout their lives. Species that reproduce by Thelytokous, thelytokous parthenogenesis and do not have males can still be classified as gonochoric. Terminology The term is derived from Greek language, Greek (''gone'', generation) + (''chorizein,'' to separate). The term gonochorism originally came from German gonochorismus. Gonochorism is also referred to as unisexualism or gonochory. Evolution Gonochorism has Convergent evolution, evolved independently multiple time ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parthenogenesis
Parthenogenesis (; from the Greek grc, παρθένος, translit=parthénos, lit=virgin, label=none + grc, γένεσις, translit=génesis, lit=creation, label=none) is a natural form of asexual reproduction in which growth and development of embryos occur in a gamete (egg or sperm) without combining with another gamete (e.g., egg and sperm fusing). In animals, parthenogenesis means development of an embryo from an unfertilized Gametophyte, egg cell. In plants, parthenogenesis is a component process of apomixis. In algae, parthenogenesis can mean the development of an embryo from either an individual sperm or an individual egg. Parthenogenesis occurs naturally in some plants, algae, invertebrate animal species (including nematodes, some tardigrades, water fleas, some scorpions, aphids, some mites, some bees, some Phasmatodea and parasitic wasps) and a few vertebrates (such as some fish, amphibians, reptiles and birds). This type of reproduction has been induced artificially ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pupa
A pupa ( la, pupa, "doll"; plural: ''pupae'') is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their life cycle, the stages thereof being egg, larva, pupa, and imago. The processes of entering and completing the pupal stage are controlled by the insect's hormones, especially juvenile hormone, prothoracicotropic hormone, and ecdysone. The act of becoming a pupa is called pupation, and the act of emerging from the pupal case is called eclosion or emergence. The pupae of different groups of insects have different names such as ''chrysalis'' for the pupae of butterflies and ''tumbler'' for those of the mosquito family. Pupae may further be enclosed in other structures such as cocoons, nests, or shells. Position in life cycle The pupal stage follows the larval stage and precedes adulthood (''imago'') in insects with complete metamorphosi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Instar
An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or assume a new form. Differences between instars can often be seen in altered body proportions, colors, patterns, changes in the number of body segments or head width. After shedding their exoskeleton (moulting), the juvenile arthropods continue in their life cycle until they either pupate or moult again. The instar period of growth is fixed; however, in some insects, like the salvinia stem-borer moth, the number of instars depends on early larval nutrition. Some arthropods can continue to moult after sexual maturity, but the stages between these subsequent moults are generally not called instars. For most insect species, an ''instar'' is the developmental stage of the larval forms of holometabolous (complete metamorphism) or nymphal forms o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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