Schizomida, also known as sprickets or short-tailed whip-scorpions, is an order of arachnids, generally less than 5 millimetres (0.20 in) in length. The order is not yet widely studied. E. O. Wilson has identified schizomids as among the "groups of organisms that desperately need experts to work on them."
The Opiliones are an order of arachnids, colloquially known as harvestmen, harvesters, harvest spiders, or daddy longlegs. As of July 2024, 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.
Ricinulei is a small order of arachnids. Like most arachnids, they are predatory, eating small arthropods. They occur today in west-central Africa (Ricinoides) and the Americas from South America to as far north as Texas, where they either inhabit leaf litter or caves. As of 2022, 103 extant species of ricinuleids have been described worldwide, all in the single family Ricinoididae. In older works they are sometimes referred to as Podogona. Due to their obscurity they do not have a proper common name, though in academic literature they are occasionally referred to as hooded tickspiders.
Scaffold web spiders or cave cobweb spiders (Nesticidae) are a family of araneomorph spiders closely allied with tangle-web spiders (Theridiidae). Like the Theridiidae, these spiders have a comb of serrated bristles on the hind tarsi that are used to pull silk bands from the spinnerets. Nesticidae contains 16 genera and about 300 species, many of which are associated with caves or overhangs. The genus Nesticus is the type for the family and is found throughout the world. The related Eidmannella has speciated considerably in Texas caves and includes some extremely localized species that are considered threatened. One species, Eidmannella pallida, is found in caves and under overhangs, but also in agricultural fields and other habitats away from such restricted areas. The genus Carpathonesticus is found in central Eurasia.
Opilioacaridae is the sole family of mites in the order Opilioacarida, made up of about 13 genera. The mites of this family are rare, large mites, and are widely considered primitive, as they retain six pairs of eyes, and abdominal segmentation. They have historically been considered separate from other mites belonging to Acariformes and Parasitiformes, but are now generally considered a subgroup of Parasitiformes based on molecular phylogenetics.
Cyatholipidae is a family of spiders first described by Eugène Simon in 1894. Most live in moist montane forest, though several species, including Scharffia rossi, live in dry savannah regions. They occur in Africa, including Madagascar, New Zealand and Australia, and one species in Jamaica. Most members of this family hang beneath sheet webs. Fossil species occur in the Eocene aged Bitterfield and Baltic Ambers, suggesting a wider geographic distribution in the past.
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 thick. 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.
Spiders have been evolving 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.
Cyphophthalmi is a suborder of harvestmen, colloquially known as mite harvestmen. Cyphophthalmi comprises 36 genera, and more than two hundred described species. The six families are currently grouped into three infraorders: the Boreophthalmi, Scopulophthalmi, and Sternophthalmi.
Baltic amber or succinite is amber from the Baltic region, home of its largest known deposits. It was produced sometime during the Eocene epoch, but exactly when is controversial. It has been estimated that this forested region provided the resin for more than 100,000 tons of amber. Today, more than 90% of the world's amber comes from Kaliningrad Oblast of Russia. It is a major source of income for the region; the local Kaliningrad Amber Combine extracted 250 tonnes of it in 2014 and 400 tonnes in 2015. Baltic amber is also found in Poland, as well as the Baltic states.
Yantaromyrmex is an extinct genus of ants first described in 2013. Members of this genus are in the subfamily Dolichoderinae of the family Formicidae, known from Middle Eocene to Early Oligocene fossils found in Europe. The genus currently contains five described species, Y. constrictus, Y. geinitzi, Y. intermedius, Y. mayrianum and Y. samlandicus. The first specimens were collected in 1868 and studied by Austrian entomologist Gustav Mayr, who originally placed the fossils in other ant genera until the fossils were reviewed and subsequently placed into their own genus. These ants are small, measuring from 4 to 6 mm in length and can be characterized by their trapezoidal shaped head-capsules and oval compound eyes that are located slightly to the rear of the capsules midpoint, with no known ocelli present.
Zherichinius is an extinct genus of ants in the subfamily Dolichoderinae known from fossils found in amber from the Middle Eocene of Sakhalin island Far eastern Russia and Bitterfeld, Germany. At the time of description the species Zherichinius horribilis and Zherichinius rapax were two of eight ant species known from Sakhalin fossils.
Burmese amber, also known as Burmite or Kachin amber, is amber from the Hukawng Valley in northern Myanmar. The amber is dated to around 100 million years ago, during the latest Albian to earliest Cenomanian ages of the mid-Cretaceous period. The amber is of significant palaeontological interest due to the diversity of flora and fauna contained as inclusions, particularly arthropods including insects and arachnids but also birds, lizards, snakes, frogs and fragmentary dinosaur remains. The amber has been known and commercially exploited since the first century AD, and has been known to science since the mid-nineteenth century. Research on the deposit has attracted controversy due to the potential role of the amber trade in funding internal conflict in Myanmar and hazardous working conditions in the mines where it is collected.
Uraraneida is an extinct order of Paleozoic arachnids related to modern spiders. Two genera of fossils have been definitively placed in this order: Attercopus from the Devonian of United States and Permarachne from the Permian of Russia. Like spiders, they are known to have produced silk, but lack the characteristic spinnerets of modern spiders, and retain elongate telsons.
Bradoponera is an extinct genus of ant in the Formicidae subfamily Proceratiinae, and is one of four genera of the subfamily. The genus contains four described species Bradoponera electrina, Bradoponera meieri, Bradoponera similis, and Bradoponera wunderlichi. The species are known from several Middle Eocene amber fossils which were found in Europe.
This list of fossil arthropods described in 2011 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 2011. The list only includes taxa at the level of genus or species.
Electromyrmex is an extinct genus of ants in the formicid subfamily Dolichoderinae. The genus contains a single described species, Electromyrmex klebsi and is known from a group of Middle Eocene fossils which were found in Europe.
Pachycondyla succinea is an extinct species of ant in the formicid subfamily Ponerinae described from fossils found in Europe. P. petrosa is one of three middle Eocene Pachycondyla species found in Baltic amber.
Rovno amber, occasionally called Ukrainian amber, is amber found in the Rivne Oblast and surrounding regions of Ukraine and Belarus. The amber is dated between Late Eocene and Early Oligocene, and suggested to be contemporaneous to Baltic amber. Major exploration and mining of the amber did not start until the 1990s.
Nylanderia pygmaea is an extinct species of formicid in the ant subfamily Formicinae known from fossils found in the Prussian Formation of the Baltic region.
