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Gonopod (millipedes)
Gonopods are specialized appendages of various arthropods used in reproduction or egg-laying. In males, they facilitate the transfer of sperm from male to female during mating, and thus are a type of intromittent organ. In crustaceans and millipedes, gonopods are modified walking or swimming legs. Gonopods may be highly decorated with elaborate structures which may play roles in sperm competition, and can be used to differentiate and identify closely related species. Gonopods generally occur in one or more pairs, as opposed to the single (un-paired) reproductive organs such as the aedeagus of insects or the penis of harvestmen. Insects In insects, gonopods are appendages of the genital segment that may be used in insemination, or that comprise the egg-laying apparatus. Crustaceans In male decapod crustaceans, gonopods are modified swimming appendages (pleopods). The anterior two pair of pleopods in males are modified for sperm transferring, with differing degree of morphologi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxidus Gracilis Gonopod SEM
''Oxidus'' is a genus of flat-backed millipedes in the family Paradoxosomatidae Paradoxosomatidae, the only family in the suborder Paradoxosomatidea (also known as Strongylosomatidea), is a family of flat-backed millipedes in the order Polydesmida. Containing nearly 200 genera and 975 species , it is one of the largest fami .... There are about nine described species in ''Oxidus''. Species These nine species belong to the genus ''Oxidus'': * '' Oxidus avia'' (Verhoeff, 1937) * '' Oxidus circofera'' Verhoeff, 1931 * '' Oxidus filarius'' Attems, 1932 * '' Oxidus gigas'' (Attems, 1953) * '' Oxidus gracilis'' (Koch, 1847) (greenhouse millipede) * '' Oxidus kosingai'' Wang, 1958 * '' Oxidus obtusus'' (Takakuwa, 1942) * '' Oxidus riukiaria'' (Verhoeff, 1940) * '' Oxidus sontus'' (Chamberlin, 1910) References Further reading * * External links * Polydesmida Millipedes of North America {{myriapoda-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helminthomorpha
Chilognatha is a subclass of the class Diplopoda, which includes the vast majority of extant millipedes, about 12,000 species. Taxonomy The classification of Chilognatha presented below is based on Shear, 2011, and Shear & Edgecombe, 2010 (extinct groups). Recent cladistic and molecular studies have challenged the traditional classification schemes above, and in particular the position of the orders Siphoniulida and Polyzoniida is not yet well established. The placement and positions of extinct groups (†) known only from fossils is tentative and not fully resolved. After each name is listed the author citation: the name of the person who coined the name or defined the group, even if not at the current rank. * Subclass Chilognatha Latrielle, 1802 ** Order † Zosterogrammida Wilson, 2005 (Chilognatha ''incertae sedis'') ** Infraclass Pentazonia Brandt, 1833 *** Order †Amynilyspedida Hoffman, 1969 *** Superorder Limacomorpha Pocock, 1894 **** Order Glomeridesmida Cook, 18 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Craspedosomatidea
Chordeumatida (from the Greek word for "sausage") is a large order of millipedes containing some 1200 species with a nearly worldwide distribution. Also known as "sausage millipedes," they possess around 30 body segments behind the head (including the telson) as adults and reach about in length. Description Chordeumatidans are relatively short-bodied, with only 26 to 32 body segments (including the telson) behind the head. They range in length from . A key feature is the presence of 6 large bristles (setae) on the dorsal surface of each body segment. The first segment ( collum) is relatively narrow, giving the appearance of a distinct "neck" in many species. The body tapers towards the rear, and the rearmost tip (telson) contains silk-producing organs (spinnerets). A dorsal groove runs down the length of the body, and some species possess paranota, lateral extensions of the exoskeleton. Paranota are also found in some other millipedes, notably Polydesmida, from which Chordeuma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterochordeumatidea
Chordeumatida (from the Greek word for "sausage") is a large order of millipedes containing some 1200 species with a nearly worldwide distribution. Also known as "sausage millipedes," they possess around 30 body segments behind the head (including the telson) as adults and reach about in length. Description Chordeumatidans are relatively short-bodied, with only 26 to 32 body segments (including the telson) behind the head. They range in length from . A key feature is the presence of 6 large bristles (setae) on the dorsal surface of each body segment. The first segment ( collum) is relatively narrow, giving the appearance of a distinct "neck" in many species. The body tapers towards the rear, and the rearmost tip (telson) contains silk-producing organs (spinnerets). A dorsal groove runs down the length of the body, and some species possess paranota, lateral extensions of the exoskeleton. Paranota are also found in some other millipedes, notably Polydesmida, from which Chordeuma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chordeumatidea
Chordeumatida (from the Greek word for "sausage") is a large order of millipedes containing some 1200 species with a nearly worldwide distribution. Also known as "sausage millipedes," they possess around 30 body segments behind the head (including the telson) as adults and reach about in length. Description Chordeumatidans are relatively short-bodied, with only 26 to 32 body segments (including the telson) behind the head. They range in length from . A key feature is the presence of 6 large bristles (setae) on the dorsal surface of each body segment. The first segment ( collum) is relatively narrow, giving the appearance of a distinct "neck" in many species. The body tapers towards the rear, and the rearmost tip (telson) contains silk-producing organs (spinnerets). A dorsal groove runs down the length of the body, and some species possess paranota, lateral extensions of the exoskeleton. Paranota are also found in some other millipedes, notably Polydesmida, from which Chordeuma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chordeumatida
Chordeumatida (from the Greek word for "sausage") is a large order of millipedes containing some 1200 species with a nearly worldwide distribution. Also known as "sausage millipedes," they possess around 30 body segments behind the head (including the telson) as adults and reach about in length. Description Chordeumatidans are relatively short-bodied, with only 26 to 32 body segments (including the telson) behind the head. They range in length from . A key feature is the presence of 6 large bristles (setae) on the dorsal surface of each body segment. The first segment ( collum) is relatively narrow, giving the appearance of a distinct "neck" in many species. The body tapers towards the rear, and the rearmost tip (telson) contains silk-producing organs (spinnerets). A dorsal groove runs down the length of the body, and some species possess paranota, lateral extensions of the exoskeleton. Paranota are also found in some other millipedes, notably Polydesmida, from which Chordeumat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinocallipus Steineri Gonopods
''Sinocallipus '' is a genus of predominantly cave-dwelling millipedes in the order Callipodida. Five of the six known species are found in limestone caves on the Indochinese Peninsula from Vietnam to southern China, and it is the only callipodidan genus entirely confined to the tropics. Individuals range from long and possess 55 to 70 segments. ''Sinocallipus'' is the sole taxon of the callipodidan suborder Sinocallipodidea, and thought to be the most primitive and sister group to all other callipodidans. In contrast to many other millipede groups, the gonopods (reproductive legs) of ''Sinocallipus'' show little variation between species, while other characters such as color, size, and other body parts differ more noticeably between species. Species All species except ''S. thai'' have been collected solely from caves, and show troglomorphic (cave-adapted) traits such as pale coloration, long antennae, and long legs. ''S. jaegeri'' and ''S. simplipodicus'' show reduced eyes, cons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Callipodida
Callipodida is an order of millipedes containing around 130 species, many characterized by crests or ridges. Description Callipodida are long and narrow millipedes, up to in length with 40-60 body segments. A dorsal groove is present running down the mid-line of the body, and many species are ornamented with longitudinal crests or ridges. Sexually mature males possess a single pair of gonopods, consisting of the modified anterior leg pair of the 7th body segment, and carried concealed within a pouch. Distribution Callipodida occurs in North America, Europe, west Asia, southern China and Southeast Asia. Classification The living (extant) Callipodida are classified into three suborders, seven families, and approximately 130 species. The genus '' Sinocallipus'', which constitutes the suborder Sinocallipodidea, is thought to be the most primitive, and a sister group to all other callipodans. A fourth, extinct, suborder was described in 2019 to accommodate '' Burmanopetalum inex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gonopore
A gonopore, sometimes called a gonadopore, is a genital pore in many invertebrates. Hexapods, including insects have a single common gonopore, except mayflies, which have a pair of gonopores. More specifically, in the unmodified female it is the opening of the common oviduct, and in the male, it is the opening of the ejaculatory duct. The position of the gonopore varies considerably between groups, but is generally constant within groups, allowing its position to be used as a "segmental marker". In Malacostraca, it is on the sixth thoracic segment; in Symphyla it is on the fourth trunk segment; in arachnids, it is on the second segment of the opisthosoma. In insects and centipedes, the gonopores are close to the animal's tail, while in millipedes they are on the third body segment behind the head, near the second pair of legs. See also * Gonopod * Gonopodium Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Selection
Sexual selection is a mode of natural selection in which members of one biological sex mate choice, choose mates of the other sex to mating, mate with (intersexual selection), and compete with members of the same sex for access to members of the opposite sex (intrasexual selection). These two forms of selection mean that some individuals have greater reproductive success than others within a population, for example because they are more Animal sexual behaviour, attractive or prefer more attractive partners to produce offspring. Successful males benefit from frequent mating and monopolizing access to one or more fertile females. Females can maximise the return on the energy they invest in reproduction by selecting and mating with the best males. The concept was first articulated by Charles Darwin who wrote of a "second agency" other than natural selection, in which competition between mate candidates could lead to speciation. The theory was given a mathematical basis by Ronald F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glomeridesmida
Glomeridesmida is an order of millipedes in the infraclass Pentazonia containing 2 families and at least 31 species. Glomeridesmida is the only living order of the superorder Limacomorpha. Glomeridesmidans are small (less than ) and somewhat flattened, and unlike other orders of Pentazonia, are unable to roll into a ball. Ocelli (eyes) are absent. Adult females in this order have 36 pairs of legs and 21 segments, counting 20 tergites plus the anal shield. Male specimens in this order are rare, unknown for all species in the family Termitodesmidae, and known for only a small number of species in the family Glomeridesmidae. Descriptions of mature males in at least three species (''Glomeridesmus spelaeus'', ''G. siamensis'', and ''G. marmoreus'') report 35 pairs of legs, including a pair of telopods, and 20 segments, one fewer than the 21 segments found in adult females. The description of an adult male of another species (''G. indus''), however, reports 37 pairs of legs, includi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
