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Orbiculariae
Orbiculariae is a potential clade of araneomorph spiders, uniting two groups that make orb webs. Phylogenetic analyses based on morphological characters have generally recovered this clade; analyses based on DNA have regularly concluded that the group is not monophyletic. The issue relates to the origin of orb webs: whether they evolved early in the evolutionary history of entelegyne spiders, with many groups subsequently losing the ability to make orb webs, or whether they evolved later, with fewer groups having lost this ability. , the weight of the evidence strongly favours the non-monophyly of "Orbiculariae" and hence the early evolution of orb webs, followed by multiple changes and losses. History Whether spiders that weave true orb webs form a coherent group, and so should be classified together, is a question that has a long history. Two groups of spiders that spin orb webs are the Uloboridae and the Araneidae. Although their webs have a very similar overall architectu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deinopoidea
The Deinopoidea or deinopoids are group of cribellate araneomorph spiders that may be treated as a superfamily. As usually circumscribed, the group contains two families: Deinopidae and Uloboridae. Some studies have produced cladograms in which the Deinopoidea are paraphyletic. A review in 2014 concluded that "at this time the monophyly of Deinopoidea remains dubious". Characteristics The group is characterized by the production of orb webs with catching threads of cribellate silk (i.e. silk made up of very fine threads produced by combing an initial thread using the spider's calamistrum). Uloborids spin vertical orb webs, very similar in shape to those made by araneids, such as the cross spider. Deinopids initially spin an orb web, which they then suspend between their front legs and use as a net to ensnare prey. Phylogeny According to one hypothesis, the two groups in which orb-weaving occurs, the cribellate deinopoids and the ecribellate araneoids, make up a single monophyl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spider Vdg
Spiders (order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species diversity among all orders of organisms. Spiders are found worldwide on every continent except for Antarctica, and have become established in nearly every land habitat. , 50,356 spider species in 132 families have been recorded by taxonomists. However, there has been debate among scientists about how families should be classified, with over 20 different classifications proposed since 1900. Anatomically, spiders (as with all arachnids) differ from other arthropods in that the usual body segments are fused into two tagmata, the cephalothorax or prosoma, and the opisthosoma, or abdomen, and joined by a small, cylindrical pedicel, however, as there is currently neither paleontological nor embryological evidence that spiders ever had a separate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spider
Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species diversity among all orders of organisms. Spiders are found worldwide on every continent except for Antarctica, and have become established in nearly every land habitat. , 50,356 spider species in 132 families have been recorded by taxonomists. However, there has been debate among scientists about how families should be classified, with over 20 different classifications proposed since 1900. Anatomically, spiders (as with all arachnids) differ from other arthropods in that the usual body segments are fused into two tagmata, the cephalothorax or prosoma, and the opisthosoma, or abdomen, and joined by a small, cylindrical pedicel, however, as there is currently neither paleontological nor embryological evidence that spiders ever had ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eresoidea
The Eresoidea or eresoids are a group of araneomorph spiders that have been treated as a superfamily. As usually circumscribed, the group contains three families: Eresidae, Hersiliidae and Oecobiidae. Studies and reviews based on morphology suggested the monophyly of the group; more recent gene-based studies have found the Eresidae and Oecobiidae to fall into different clades, placing doubt on the acceptability of the taxon. Some researchers have grouped Hersiliidae and Oecobiidae into the separate superfamily Oecobioidea, a conclusion supported in a 2017 study, which does not support Eresoidea. Phylogeny Some largely morphology-based phylogenetic studies that included the three families assigned to the Eresoidea supported their monophyly, with the internal structure of the clade being as shown below. Eresoidea was placed as basal in the Entelegynae, with its precise position relative to the Palpimanoidea, also basal, varying. In 2015, Jonathan A. Coddington summarized this a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Araneidae
Orb-weaver spiders are members of the spider family Araneidae. They are the most common group of builders of spiral wheel-shaped webs often found in gardens, fields, and forests. The English word "orb" can mean "circular", hence the English name of the group. Araneids have eight similar eyes, hairy or spiny legs, and no stridulating organs. The family has a cosmopolitan distribution, including many well-known large or brightly colored garden spiders. With 3,108 species in 186 genera worldwide, the Araneidae comprise the third-largest family of spiders (behind the Salticidae and Linyphiidae). Araneid webs are constructed in a stereotypical fashion, where a framework of nonsticky silk is built up before the spider adds a final spiral of silk covered in sticky droplets. Orb webs are also produced by members of other spider families. The long-jawed orb weavers (Tetragnathidae) were formerly included in the Araneidae; they are closely related, being part of the superfamily Araneo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philipp Bertkau
Philipp Bertkau (11 January 1849 – 22 October 1894) was a German zoologist born in Cologne. He studied natural sciences at the University of Bonn, where in 1872 he earned his doctorate. In 1873 he became an assistant at the botanical institute in Munich, and during the following spring was an assistant at the zoological institute at Bonn. In 1882 he was appointed professor at the Agricultural Academy of Poppelsdorf, and in 1890 became curator at the Institute of Zoology and Comparative Anatomy. Bertkau is remembered for his work involving the anatomy and physiology of spiders, research on sense of smell in butterflies, and anatomical studies of hermaphroditic arthropods. At Bonn he was secretary of ''Bonner Gesellschaft für Naturgeschichte'' (Bonn Society of Natural History). He is the taxonomic authority of the families Anyphaenidae, Hahniidae, Sparassidae and Zoropsidae, and of the genera ''Ancylometes'', ''Chalcoscirtus'', ''Comaroma'' and ''Diplocephalus''. Selected wor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nicodamidae
Nicodamidae is a family of araneomorph spiders with about thirty species in seven genera. They are small to medium-sized spiders found near the ground of eucalypt forest in small sheet webs. The species of this family are only present in Australia and Papua New Guinea. In most cases the cephalothorax and legs are uniformly red and the abdomen black, for which these species are sometimes called the "red and black spiders". Taxonomy The family Nicodamidae was established by Eugène Simon in 1897 for his newly described species ''Nicodamus dimidiatus'' (now ''Dimidamus dimidiatus''). Mark Harvey published a major review of the family in 1995. At the time of the review, only two genera were accepted, ''Nicodamus'' from Australia and New Guinea, and '' Megadictyna'' from New Zealand. Based on a morphological cladistic analysis, Harvey divided the family into two subfamilies, Nicodaminae and Megadictyninae, and erected seven new genera. In 1967, Pekka T. Lehtinen proposed that Megadict ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RTA Clade
The RTA clade is a clade of araneomorph spiders, united by the possession of a retrolateral tibial apophysis – a backward-facing projection on the tibia of the male pedipalp. The clade contains over 21,000 species, almost half the current total of about 46,000 known species of spider. Most of the members of the clade are wanderers and do not build webs. Despite making up approximately half of all modern spider diversity, there are no unambiguous records of the group from the Mesozoic and molecular clock evidence suggests that the group began to diversify during the Late Cretaceous. Families In 2005, Coddington included 39 families in a cladogram showing the RTA clade: *Agelenidae *Amaurobiidae *Ammoxenidae *Amphinectidae (paraphyletic; merged into Desidae) *Anyphaenidae *Cithaeronidae *Clubionidae *Corinnidae *Cryptothelidae *Ctenidae *Desidae *Dictynidae *Gallieniellidae *Gnaphosidae *Lamponidae *Liocranidae *Lycosidae *Miturgidae (paraphyletic) *Oxyopidae *Philodromidae *Phyx ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladogram
A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to descendants, nor does it show how much they have changed, so many differing evolutionary trees can be consistent with the same cladogram. A cladogram uses lines that branch off in different directions ending at a clade, a group of organisms with a last common ancestor. There are many shapes of cladograms but they all have lines that branch off from other lines. The lines can be traced back to where they branch off. These branching off points represent a hypothetical ancestor (not an actual entity) which can be inferred to exhibit the traits shared among the terminal taxa above it. This hypothetical ancestor might then provide clues about the order of evolution of various features, adaptation, and other evolutionary narratives about ance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Araneoidea
Araneoidea is a taxon of araneomorph spiders, termed "araneoids", treated as a superfamily. As with many such groups, its circumscription has varied; in particular some families that had at one time moved to the Palpimanoidea have more recently been restored to Araneoidea. A 2014 treatment includes 18 families, with the araneoids making up about 26% of the total number of known spider species; a 2016 treatment includes essentially the same taxa, but now divided into 17 families. Taxonomy Many of the differences in circumscription concern the relationship between Araneoidea and Palpimanoidea. In 1984, Raymond R. Forster and Norman I. Platnick proposed that some groups previously considered araneoid actually belonged in the distantly related Palpimanoidea, including the families Holarchaeidae, Micropholcommatidae, Mimetidae and Pararchaeidae. Subsequent phylogenetic studies have rejected this proposal, firmly placing these four families in Araneoidea (some included in other famil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deinopidae
Deinopidae, also known as net casting spiders, is a family of cribellate spiders first described by Carl Ludwig Koch in 1850. It consists of stick-like elongated spiders that catch prey by stretching a web across their front legs before propelling themselves forward. These unusual webs will stretch two or three times their relaxed size, entangling any prey that touch them. The posterior median eyes have excellent night vision, allowing them to cast nets accurately in low-light conditions. These eyes are larger than the others, and sometimes makes these spiders appear to only have two eyes. Ogre-faced spiders (''Deinopis'') are the best known genus in this family. The name refers to the perceived physical similarity to the mythological creature of the same name. This family also includes the humped-back spiders (''Menneus''). They are distributed through tropics worldwide from Australia to Africa and the Americas. In Florida, ''Deinopis'' often hangs upside down from a silk line und ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogeny
A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical or genetic characteristics. All life on Earth is part of a single phylogenetic tree, indicating common ancestry. In a ''rooted'' phylogenetic tree, each node with descendants represents the inferred most recent common ancestor of those descendants, and the edge lengths in some trees may be interpreted as time estimates. Each node is called a taxonomic unit. Internal nodes are generally called hypothetical taxonomic units, as they cannot be directly observed. Trees are useful in fields of biology such as bioinformatics, systematics, and phylogenetics. ''Unrooted'' trees illustrate only the relatedness of the leaf nodes and do not require the ancestral root to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
