Crevice weavers Temporal range: | |
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Kukulcania hibernalis , male | |
Filistatid web | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Subphylum: | Chelicerata |
Class: | Arachnida |
Order: | Araneae |
Infraorder: | Araneomorphae |
Family: | Filistatidae Ausserer, 1867 |
Diversity | |
19 genera, 185 species | |
Distribution is approximate |
Crevice weaver spiders (Filistatidae) comprise cribellate spiders with features that have been regarded as "primitive" for araneomorph spiders. They are weavers of funnel or tube webs. The family contains 18 genera and more than 120 described species worldwide.
One of the most abundant members of this family in the Americas is the southern house spider (Kukulcania hibernalis). Named after the fierce Meso-American god Kukulkan, the females are large (up to nearly 20 mm) dark-colored spiders and males are light brown, smaller (about 10 mm), but more long-legged and with palps that are held together in front of their carapaces like the horn of a unicorn. The males also have a darker streak on the center of the dorsal carapace that causes them to be often mistaken for brown recluse spiders. The tiny members of the genus Filistatinella are like miniature versions of Kukulcania. The nominate genus Filistata is Afro-Eurasian in distribution. In many older books the species from the Americas now placed in the genus Kukulcania are placed in Filistata.
A striking visual characteristic of the family, beside dimorphism, is the unusual upward bend encountered near the femur of the first pair of legs. While resembling hydraulic muscle mechanisms akin to arthropods, this modification actually allows the spider to retain the prey directly from the crevice it occupies. Also, if the larger prey ever tries to pull it from the crevice, the spider can use these legs to "grab" to the side walls and hence make it difficult. Many Kukulcania species also use them to dig holes in the soft ground at a 25- to 30-degree angle.[ citation needed ]
The family Filistatidae was created in 1867 by Anton Ausserer. [1] It was based on the species he called Filistata bicolor (now Filistata insidiatrix ), a Mediterranean species also found in southern Austria. [2] [3]
On the basis of the features of the male and female genitalia, the family was placed in the Haplogynae, usually as the sister taxon of the remaining members of the group. [4] However, unlike the other haplogynes, Filistatidae are cribellate and do not show a decrease in the number of segments of the anterior lateral spinnerets. [5] They have other features which have been regarded as "primitive": an M-shaped intestine, only leg IV moving while combing silk, and posterior book lung leaves being present in early juveniles. [6] A 2013 study based on molecular evidence placed the family as sister to a clade consisting of Hypochilidae and the remaining haplogynes. [7] The precise phylogenetic position of the family was described in 2014 as "one of the most enigmatic problems in spider phylogeny". [5]
A 2015 study, based on genomic data, places Filistatidae with Hypochilidae in a clade outside most of the families previously placed in Haplogynae: [8]
Araneomorphae |
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This placement suggests that features that were thought to be "primitive" to araneomorph spiders as a whole (such as an M-shaped midgut) could actually be novel derived features (synapomorphies) of the Hypochilidae-Filistatidae clade. [8]
As of April 2019 [update] , the World Spider Catalog accepts the following genera: [9]
The Araneomorphae 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, where they point straight down. Araneomorphs comprise the vast majority of living spiders.
Lampshade spiders, family Hypochilidae, are among the most primitive of araneomorph spiders. There are two 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, 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.
The southern house spider is a species of large spider in the family Filistatidae. Currently given the scientific name Kukulcania hibernalis, it was formerly known as Filistata hibernalis. Found in the Americas, it exhibits strong sexual dimorphism. It is occurs in the southern states of the USA, throughout Central America and some of the Caribbean, to southern Brazil, Uruguay and Argentina. The males may be mistaken for brown recluses because the two have similar coloration and body structure. However, compared to the brown recluse, male southern house spiders are typically larger in size, lack the distinctive violin shape on their cephalothorax, and have unusually long slender pedipalps. The females are dark brown or black and more compact. Both sexes may grow to be roughly 2 inches (5.1 cm) across, with the males typically having longer legs, and the females often having larger, bulbous bodies. The abdomen of the southern house spider is covered with fine velvety light gray hair.
Spider taxonomy is that part of taxonomy that is concerned with the science of naming, defining and classifying all spiders, members of the Araneae order of the arthropod class Arachnida with more than 48,500 described species. However, there are likely many species that have escaped the human eye to this day, and many specimens stored in collections waiting to be described and classified. It is estimated that only one third to one half of the total number of existing species have been described.
Cribellum literally means "little sieve", and in biology the term generally applies to anatomical structures in the form of tiny perforated plates.
Austrochilidae is a small spider family with nine species in two genera. Austrochilus and Thaida are endemic to the Andean forest of central and southern Chile and adjacent Argentina.
The Dionycha are a clade of spiders (Araneomorphae:Entelegynae), characterized by the possession of two tarsal claws with tufts of hairs (setae) beside them, which produce strong adhesion, enabling some species to climb glass. The circumscription of the group has varied widely; a 2021 analysis resulted in about 20 families, including Salticidae, Gnaphosidae, and Clubionidae.
The Leptonetoidea are a superfamily of haplogyne araneomorph spiders with three families. Phylogenetic studies have provided weak support for the relationship among the families. The placement of one of the families within the Haplogynae has been questioned.
The Dysderoidea are a clade or superfamily of araneomorph spiders. The monophyly of the group, initially consisting of the four families Dysderidae, Oonopidae, Orsolobidae and Segestriidae, has consistently been recovered in phylogenetic studies. In 2014, a new family, Trogloraptoridae, was created for a recently discovered species Trogloraptor marchingtoni. It was suggested that Trogloraptoridae may be the most basal member of the Dysderoidea clade. However, a later study found that Trogloraptoridae was placed outside the Dysderoidea and concluded that it was not part of this clade.
The Austrochiloidea or austrochiloids are a group of araneomorph spiders, treated as a superfamily. The taxon contains two families of eight-eyed spiders:
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.
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.
Kukulcania is a genus of crevice weavers that was first described by Pekka T. Lehtinen in 1967. It is named after Kukulkan, a Mesoamerican serpent deity.
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. As of September 2018, 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.
Filistata maguirei is a species of the araneomorph spider family Filistatidae.
Austrochilus is a genus of South American cribellate araneomorph spiders in the family Austrochilidae, first described by H. Zapfe in 1955.
Andoharano is a genus of African crevice weavers that was first described by Pekka T. Lehtinen in 1967.
Strotarchus is a genus of araneomorph spiders in the family Cheiracanthiidae that was first described by Eugène Louis Simon in 1888. Originally added to the Clubionidae, it was moved to the Miturgidae in 1967, and to the Cheiracanthiidae in 2014. It is considered a senior synonym of Marcellina and Coreidon.
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.