The Opiliones are an order of arachnids colloquially known as harvestmen, harvesters, or daddy longlegs. As of April 2017, over 6,650 species of harvestmen have been discovered worldwide, although the total number of extant species may exceed 10,000. The order Opiliones includes five suborders: Cyphophthalmi, Eupnoi, Dyspnoi, Laniatores, and Tetrophthalmi, which were named in 2014.
The family Dipluridae, known as curtain-web spiders are a group of spiders in the infraorder Mygalomorphae, that have two pairs of booklungs, and chelicerae (fangs) that move up and down in a stabbing motion. A number of genera, including that of the Sydney funnel-web spider (Atrax), used to be classified in this family but have now been moved to Hexathelidae.
The ray spiders (Theridiosomatidae) are a family of spiders first described by Eugène Simon in 1881. They are most recognizable for their construction of cone-shaped webs.
Archaeidae, also known as assassin spiders and pelican spiders, is a spider family with about ninety described species in five genera. It contains small spiders, ranging from 2 to 8 millimetres long, that prey exclusively on other spiders. They are unusual in that they have "necks", ranging from long and slender to short and fat. The name "pelican spider" refers to these elongated jaws and necks used to catch their prey. Living species of Archaeidae occur in South Africa, Madagascar and Australia, with the sister family Mecysmaucheniidae occurring in southern South America and New Zealand.
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 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.
The evolution of spiders has been ongoing for at least 380 million years. The group's origins lie within an arachnid sub-group defined by the presence of book lungs ; the arachnids as a whole evolved from aquatic chelicerate ancestors. More than 45,000 extant species have been described, organised taxonomically in 3,958 genera and 114 families. There may be more than 120,000 species. Fossil diversity rates make up a larger proportion than extant diversity would suggest with 1,593 arachnid species described out of 1,952 recognized chelicerates. Both extant and fossil species are described annually by researchers in the field. Major developments in spider evolution include the development of spinnerets and silk secretion.
The Wessex Formation is a fossil-rich English geological formation that dates from the Berriasian to Barremian stages of the Early Cretaceous. It forms part of the Wealden Group and underlies the younger Vectis Formation and overlies the Durlston Formation. The dominant lithology of this unit is mudstone with some interbedded sandstones. It is exposed in both the Isle of Purbeck and the Isle of Wight. While the Purbeck sections are largely barren of vertebrate remains, the Isle of Wight sections are well known for producing the richest and most diverse fauna in Early Cretaceous Europe. Regional correlations include the Upper Weald Clay of the United Kingdom, the Sainte-Barbe Clays Formation of Belgium, and the La Huérguina and Camarillas Formations of Spain.
Boganiidae is a family of beetles, in the suborder Polyphaga. Members of the family are found in southern Africa, Australia and New Caledonia. Adults and larvae are pollenivorous, feeding on the pollen of cycads and Myrtaceae, Meliaceae, Cunoniaceae and Elaeocarpaceae angiosperms. Metacucujus and Paracucujus act as pollinators for cycads Encephalartos and Macrozamia respectively. This association with cycads goes back to at least the Mid-Cretaceous, with an extinct form being found with preserved cycad pollen in 99 million year old Burmese amber.
Hemiphlebiidae is a family of damselflies, it contains only one extant species, the ancient greenling, native to Southern Australia and Tasmania. The fossil record of the group extends back to the Late Jurassic.
This list of fossil arthropods described in 2012 is a list of new taxa of trilobites, fossil insects, crustaceans, arachnids and other fossil arthropods of every kind that have been described during the year 2012. The list only includes taxa at the level of genus or species.
This list of fossil arthropods described in 2015 is a list of new taxa of trilobites, fossil insects, crustaceans, arachnids and other fossil arthropods of every kind that have been described during the year 2015. The list only includes taxa at the level of genus or species.
This list of fossil arthropods described in 2010 is a list of new taxa of trilobites, fossil insects, crustaceans, arachnids and other fossil arthropods of every kind that have been described during the year 2010. The list only includes taxa at the level of genus or species.
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.
New Jersey Amber, sometimes called Raritan amber, is amber found in the Raritan and Magothy Formations of the Central Atlantic (Eastern) coast of the United States. The amber is dated to be of Late Cretaceous, Turonian age, based on pollen analysis of the host formations. The amber has been known since the nineteenth century, with several of the old clay-pit sites now producing many amber specimens for study. A number of organism fossils have been described from inclusions in the amber, including fungi, plants, tardigrades, insects, and feathers. The first identified Cretaceous age ant was described from a fossil found in New Jersey in 1966.
Seppo is an extinct genus of spiders, possibly of the superfamily Palpimanoidea, that lived about 180 million years ago, in the Early Jurassic of what is now Europe. The sole species Seppo koponeni is known from a single fossil from Grimmen, Germany. With the scorpion Liassoscorpionides, it is one of the two only known arachnids from the Lower Jurassic of Germany. Seppo is the first unequivocal Early Jurassic spider, and was recovered from the Green Series member of the Toarcian Ciechocinek Formation.
Dungeyella is an extinct genus of chironomid from the Wealden amber of the Isle of Wight, UK.
Avicularioidea is a clade of mygalomorph spiders, one of the two main clades into which mygalomorphs are divided. It has been treated at the rank of superfamily.
Baalzebub is a genus of ray spiders first described by Jonathan A. Coddington in 1986. Spiders in this genus typically live in dark environments, like caves.
Burmese amber is fossil resin dating to the early Late Cretaceous Cenomanian age recovered from deposits in the Hukawng Valley of northern Myanmar. It is known for being one of the most diverse Cretaceous age amber paleobiotas, containing rich arthropod fossils, along with uncommon vertebrate fossils and even rare marine inclusions. A mostly complete list of all taxa described up until 2018 can be found in Ross 2018; its supplement Ross 2019b covers most of 2019.
Lagonomegopidae is an extinct family of spiders known from the Cretaceous period. Members of the family are distinguished by a large pair of eyes, positioned on the anterolateral flanks of the carapace, with the rest of the eyes being small. They have generally been considered members of Palpimanoidea, but this has recently been questioned. Members of the family are known from the late Early Cretaceous (Albian) to near the end of the Late Cretaceous (Campanian) of Eurasia, North America and the Middle East, which was then attached to Africa as part of Gondwana. They are generally assumed to have been free living hunters as opposed to web builders.
