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Araneomorphae
The Araneomorphae (also called the Labidognatha or "true spiders") are an infraorder of spiders. They are distinguishable by chelicerae (fangs) that point diagonally forward and cross in a pinching action, in contrast to the Mygalomorphae (tarantulas and their close kin), where they point straight down. Araneomorphs comprise the vast majority (about 93%) of living spiders. Distinguishing characteristics Most spider species are Araneomorphae, which have chelicerae, fangs that face towards each other, increasing the orientations that they can employ during prey-capture. They have fewer book lungs (when present) – usually one pair – and the females typically live one year. The Mygalomorphae have chelicerae, fangs that face towards the ground, and which are parallel to the long axis of the spider's body, thus they have only one orientation they can employ during prey capture. They have two pairs of book lungs, and the females often live many years. Image:Cheiracanthium pun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spider
Spiders (order (biology), order Araneae) are air-breathing arthropods that have eight limbs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude spider silk, silk. They are the largest order of arachnids and rank seventh in total species diversity among all Order (biology), orders of organisms. Spiders are found worldwide on every continent except Antarctica, and have become established in nearly every land habitat. , 53,034 spider species in 136 Family (biology), families have been recorded by Taxonomy (biology), taxonomists. However, there has been debate among scientists about how families should be classified, with over 20 different classifications proposed since 1900. Anatomy, Anatomically, spiders (as with all arachnids) differ from other arthropods in that the usual body segmentation (biology), segments are fused into two Tagma (biology), tagmata, the cephalothorax or prosoma, and the opisthosoma, or abdomen, and joined by a small, cylindr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haplogynae
The Haplogynae or haplogynes are one of the two main groups into which araneomorph spiders have traditionally been divided, the other being the Entelegynae. Morphological phylogenetic studies suggested that the Haplogynae formed a clade; more recent molecular phylogenetic studies refute this, although many of the ecribellate haplogynes do appear to form a clade, Synspermiata. Unlike the Entelegynae, haplogynes lack hardened (sclerotized) female genitalia ( epigynes). Most of the species within this group have six eyes, as opposed to most other spiders. Spiders in the genus '' Tetrablemma'' ( Tetrablemmidae) have only four eyes, as do some members of the family Caponiidae; caponiids may even have only two eyes. However, spiders in the family Plectreuridae have the normal eight eyes. Phylogeny The Haplogynae are one of the two major groups into which araneomorph spiders were traditionally divided, the other being the Entelegynae. In 2005, Coddington summarized the relatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Austrochiloidea
The Austrochiloidea or austrochiloids are a group of araneomorph spiders, treated as a superfamily. The taxon contains two families of eight-eyed spiders: * Austrochilidae Zapfe, 1955 * Gradungulidae Forster, 1955 Phylogeny The monophyly of the Austrochiloidea has been supported in both morphological and molecular phylogenetic studies. The position of the clade relative to two much larger groups, Haplogynae The Haplogynae or haplogynes are one of the two main groups into which araneomorph spiders have traditionally been divided, the other being the Entelegynae. Morphological phylogenetic studies suggested that the Haplogynae formed a clade; more re ... and Entelegynae, has varied. A summary in 2005 showed the Austrochiloidea to be basal to both groups: Two studies have placed representatives of the Austrochiloidea between the two, suggesting they have more derived characters than previously supposed: References {{Taxonbar, from=Q54482 Araneomorphae Arachnid su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tarantula
Tarantulas comprise a group of large and often hairy spiders of the family Theraphosidae. , 1,100 species have been identified, with 166 genera. The term "tarantula" is usually used to describe members of the family Theraphosidae, although many other members of the same infraorder ( Mygalomorphae) are commonly referred to as "tarantulas" or "false tarantulas". Some of the more common species have become popular in the exotic pet trade. Many New World species kept as pets have setae known as urticating hairs that can cause irritation to the skin, and in extreme cases, cause damage to the eyes. Overview Like all arthropods, the tarantula is an invertebrate that relies on an exoskeleton for muscular support.Pomeroy, R. (2014, February 4). Pub. Real Clear Science, "Spiders, and Their Amazing Hydraulic Legs and Genitalia". Retrieved October 13, 2019, from https://www.realclearscience.com/blog/2013/02/spiders-their-amazing-hydraulic-legs-and-genitals.html. Like other Arachni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Entelegynae
The Entelegynae or entelegynes are a subgroup of araneomorph spiders, the largest of the two main groups into which the araneomorphs were traditionally divided. Females have a genital plate ( epigynum) and a "flow through" fertilization system; males have complex palpal bulbs. Molecular phylogenetic studies have supported the monophyly of Entelegynae (whereas the other traditional subgroup, the Haplogynae, has been shown not to be monophyletic). The clade contains both cribellate and ecribellate spiders. Characterization The Entelegynae are characterized primarily by the nature of the female genital system. The ancestral ( plesiomorphic) system is found in non-entelegyne spiders, where there is a single external genital opening in the female's abdomen. One or more males inject sperm from their palpal bulbs via this opening; the sperm is usually stored in special spermathecae (absent in some spiders, e.g. '' Pholcus''). When eggs are released from the ovaries, sperm is also r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synspermiata
Synspermiata is a clade of araneomorph spiders, comprising most of the former " haplogynes". They are united by having simpler genitalia than other araneomorph spiders, lacking a cribellum, and sharing an evolutionary history of synspermia – a particular way in which spermatozoa are grouped together when transferred to the female. Synspermia Spermatozoa are produced in a multi-step process. A primary spermatocyte with the full diploid number of chromosomes divides to form two secondary spermatocytes which are haploid, i.e., each has half the diploid number of chromosomes. Each secondary spermatocyte then divides to produce two spermatids which undergo further development to form spermatozoa. In synspermia, two or more spermatids from the same spermatocyte fuse together and are enclosed in an envelope, forming a "capsule". This contrasts with cleistospermia, where the capsules enclose individual spermatozoa. After transfer to the female in either form, decapsulation and activa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypochilidae
Lampshade spiders, family Hypochilidae, are among the most primitive of araneomorph spiders. There are two genus, genera and twelve species currently recognized. Like mygalomorphs, most hypochilids have two pairs of book lungs, but like araneomorphs they have intersecting fangs, with the exception of some species which have chelicerae in an angle that is neither orthognathous or labidognathous. These long-legged spiders build typical "lampshade" style webs under overhangs and in caves. In the United States the fauna is primarily associated with the Appalachian Mountains, Appalachian, Rocky Mountains, Rocky and California Mountains. Ten of the known species are found in these ranges, all in the genus ''Hypochilus''. The genus ''Ectatosticta'' is found in China. In one analysis, the Hypochilidae are a sister clade to the Neocribellatae, which contains all other spider species in the Araneomorphae (Coddington & Levi, 1991, p. 576). A more recent study groups them with the Haplog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
