Trilobites are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period and they flourished throughout the lower Paleozoic before slipping into a long decline, when, during the Devonian, all trilobite orders except the Proetida died out. The last trilobites disappeared in the mass extinction at the end of the Permian about 251.9 million years ago. Trilobites were among the most successful of all early animals, existing in oceans for almost 270 million years, with over 22,000 species having been described.
Ticks are parasitic arachnids of the order Ixodida. They are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living by feeding on the blood of mammals, birds, and sometimes reptiles and amphibians. The timing of the origin of ticks is uncertain, though the oldest known tick fossils are from the Cretaceous period, around 100 million years old. Ticks are widely distributed around the world, especially in warm, humid climates.
Mites are small arachnids. Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari. However, most recent genetic analyses do not recover the two as each other's closest relative within Arachnida, rendering the group non-monophyletic. Most mites are tiny, less than 1 mm (0.04 in) in length, and have a simple, unsegmented body plan. The small size of most species makes them easily overlooked; some species live in water, many live in soil as decomposers, others live on plants, sometimes creating galls, while others are predators or parasites. This last type includes the commercially destructive Varroa parasite of honey bees, as well as scabies mites of humans. Most species are harmless to humans, but a few are associated with allergies or may transmit diseases.
Arbovirus is an informal name for any virus that is transmitted by arthropod vectors. The term arbovirus is a portmanteau word. Tibovirus is sometimes used to more specifically describe viruses transmitted by ticks, a superorder within the arthropods. Arboviruses can affect both animals and plants. In humans, symptoms of arbovirus infection generally occur 3–15 days after exposure to the virus and last three or four days. The most common clinical features of infection are fever, headache, and malaise, but encephalitis and viral hemorrhagic fever may also occur.
Bartonella is a genus of Gram-negative bacteria. It is the only genus in the family Bartonellaceae. Facultative intracellular parasites, Bartonella species can infect healthy people, but are considered especially important as opportunistic pathogens. Bartonella species are transmitted by vectors such as fleas, sand flies, and mosquitoes. At least eight Bartonella species or subspecies are known to infect humans.
Bunyavirales is an order of segmented negative-strand RNA viruses with mainly tripartite genomes. Member viruses infect arthropods, plants, protozoans, and vertebrates. It is the only order in the class Ellioviricetes. The name Bunyavirales derives from Bunyamwera, where the original type species Bunyamwera orthobunyavirus was first discovered. Ellioviricetes is named in honor of late virologist Richard M. Elliott for his early work on bunyaviruses.
Ixodes holocyclus, commonly known as the Australian paralysis tick, is one of about 75 species in the Australian tick fauna and is considered the most medically important. It can cause paralysis by injecting neurotoxins into its host. It is usually found in a 20-kilometre wide band following the eastern coastline of Australia. Within that range, Ixodes holocyclus is the tick most frequently encountered by humans and their pets. Because the same area includes Australia's most densely populated regions, bites on people, pets and livestock are relatively common.
Nuttalliella namaqua is a tick found in southern Africa from Tanzania to Namibia and South Africa, which is placed in its own family, Nuttalliellidae. It can be distinguished from ixodid ticks and argasid ticks by a combination of characteristics including the position of the stigmata, lack of setae, strongly corrugated integument, and form of the fenestrated plates. It is the most basal lineage of ticks.
George Henry Falkiner Nuttall FRS was an American-British bacteriologist who contributed much to the knowledge of parasites and of insect carriers of diseases. He made significant innovative discoveries in immunology, about life under aseptic conditions, in blood chemistry, and about diseases transmitted by arthropods, especially ticks. He carried out investigations into the distribution of Anopheline mosquitoes in England in relation to the previous prevalence of malaria there. With William Welch he identified the organism responsible for causing gas gangrene.
Jianfengia is an extinct genus of Middle Cambrian (Atdabanian) megacheiran arthropod found in the Maotianshan Shale Lagerstätte of China. It contains the single species Jianfengia multisegmentalis. The body is extremely elongated, though the animal itself was relatively small at less than 4 centimetres (1.6 in) in length. The head has a pair of stalked eyes, a hypostome/labrum complex, a pair of great appendages with five podomeres, and four pairs of biramous limbs. The maximum known number of trunk segments is 27, though most known specimens have 20, which are associated with pairs of biramous appendages, and the body ends with a telson spine. It has been placed as a member of the family Jiangfengiidae, alongside Fortiforceps and Sklerolibyon as well as possibly Parapeytoia.
Anaplasma phagocytophilum is a Gram-negative bacterium that is unusual in its tropism to neutrophils. It causes anaplasmosis in sheep and cattle, also known as tick-borne fever and pasture fever, and also causes the zoonotic disease human granulocytic anaplasmosis.
The (pan)arthropod head problem is a long-standing zoological dispute concerning the segmental composition of the heads of the various arthropod groups, and how they are evolutionarily related to each other. While the dispute has historically centered on the exact make-up of the insect head, it has been widened to include other living arthropods, such as chelicerates, myriapods, and crustaceans, as well as fossil forms, such as the many arthropods known from exceptionally preserved Cambrian faunas. While the topic has classically been based on insect embryology, in recent years a great deal of developmental molecular data has become available. Dozens of more or less distinct solutions to the problem, dating back to at least 1897, have been published, including several in the 2000s.
Amblyomma americanum, also known as the lone star tick, the northeastern water tick, or the turkey tick, is a type of tick indigenous to much of the eastern United States and Mexico, that bites painlessly and commonly goes unnoticed, remaining attached to its host for as long as seven days until it is fully engorged with blood. It is a member of the phylum Arthropoda, class Arachnida. The adult lone star tick is sexually dimorphic, named for a silvery-white, star-shaped spot or "lone star" present near the center of the posterior portion of the adult female shield (scutum); adult males conversely have varied white streaks or spots around the margins of their shields.
Ticks are insects known for attaching to and sucking blood from land-dwelling animals. Ticks fall under the category of 'arthropod', and while they are often thought of in the context of disease transmission, they are also known to cause direct harm to hosts through bites, toxin release, and infestation. Infestation can cause symptoms ranging from mild to severe and may even cause death. Hosts can include any number of vertebrates, though humans and livestock are more likely to be the interest of researchers.
Ornithodoros moubata, commonly known as the African hut tampan or the eyeless tampan, is a species of tick in the family Argasidae. It is an ectoparasite and vector of relapsing fever in humans, and African swine fever in pigs.
Phytophilaspis is a phosphatized genus of trilobite-like arthropod with eyes, found in association with algal remains. It dwelt in well-lit, shallow waters.
The cephalon is the head section of an arthropod. It is a tagma, i.e., a specialized grouping of arthropod segments. The word cephalon derives from the Greek κεφαλή (kephalē), meaning "head".
The hypostome is the hard mouthpart of trilobites found on the ventral side of the cephalon (head). The hypostome can be classified into three types based on whether they are permanently attached to the rostrum or not and whether they are aligned to the anterior dorsal tip of the glabella.
Emucarididae is an extinct family of soft-shelled trilobite-like arthropods (nektaspids) from the Lower Cambrian of South Australia and South China. It contains only two genera – Emucaris and Kangacaris. Two species were described in 2010 from specimens recovered from Emu Bay Shale Lagerstätte, one species in 2012 from the Maotianshan Shales. It is classified under the order Nektaspida, and is a sister-group to the families Liwiidae and Naraoiidae.
Mites are small crawling animals related to ticks and spiders. Most mites are free-living and harmless. Other mites are parasitic, and those that infest livestock animals cause many diseases that are widespread, reduce production and profit for farmers, and are expensive to control.
