harvestmen scientific name
Harvestmen are a scientifically neglected group. [41][47][48] This strategy can be costly because harvestmen do not regenerate their legs,[21] and leg loss reduces locomotion, speed, climbing ability, sensory perception, food detection, and territoriality. It potentially serves to confuse and deflect any identification of the exact location of their bodies. Eisner, T., Alsop, D., Meinwald, J., 1978. Their phylogenetic position within the Arachnida is disputed; their closest relatives may be the mites (Acari) or the Novogenuata (the Scorpiones, Pseudoscorpiones, and Solifugae). Diet: small insects, fruit, fungi. The legs continue to twitch after they are detached because 'pacemakers' are located in the ends of the first long segment (femur) of their legs. These arachnids defend themselves by secreting a foul-smelling fluid. Bees, Ants, & Wasps. Most species are nocturnal and colored in hues of brown, although a number of diurnal species are known, some of which have vivid patterns in yellow, green, and black with varied reddish and blackish mottling and reticulation. Domínguez, M., Escalante, I., Carrasco-Rueda, F., Figuerola-Hernández, C.E., Marta Ayup, M., Umaña, M.N., Ramos, D., González-Zamora, A., Brizuela, C., Delgado, W., Pacheco-Esquivel, J., 2016. Can. Find out more about the nature and wildlife outside your window. Soc. The Ecological Significance of Leg Autotomy for Climbing Temperate Species of Harvestmen (Arachnida, Opiliones, Sclerosomatidae). These aggregations may number 200 individuals in the Laniatores, and more than 70,000 in certain Eupnoi. Press Camb. Carl Ludwig Koch, Maximilian Perty (1830s-1850s) Harvestman are a group of arachnids with over 6,650 species discovered so far. [34], Individuals that are able to detect potential threats can flee rapidly from attack. The feeding apparatus (stomotheca) differs from most arachnids in that Opiliones can swallow chunks of solid food, not only liquids. Eisner, T., Eisner, M., Siegler, M., 2005. The males of some species offer a secretion (nuptial gift) from their chelicerae to the female before copulation. Engl. Other harvestmen may exhibit mimicry to resemble other species’ appearances. [41][48][47][49], Autotomized legs provide a further defense from predators because they can twitch for 60 seconds to an hour after detachment. 40, 259–261. Gnaspini, P., Cavalheiro, A.J., 1998. J. Zool. [31][32] Thanatosis is used as a second line of defense when detected by a potential predator and is commonly observed within the Dyspnoi and Laniatores suborders,[29] with individuals becoming rigid with legs either retracted or stretched. The oldest known harvestman, from the 410-million-year-old Devonian Rhynie chert, displayed almost all the characteristics of modern species, placing the origin of harvestmen in the Silurian, or even earlier. Lacking sensory (rather than locomotive) legs affects locomotion but not food detection in the harvestman Holmbergiana weyenberghi. Other important taxonomists in this field include: [38], To deflect attacks and enhance escape, long-legged species – commonly known as daddy long-legs – from the Eupnoi suborder, use two mechanisms. In short-legged species, this may not be obvious. Ecol. They can be separated from spiders which have two distinct body segments because harvestmen have the entire body as one unit. The best-known taxa are the long-legged Eupnoi harvestmen, although they comprise less than a third of the total opilionid diversity. As a consequence, most known fossils have been preserved within amber. Hara, M.R., Gnaspini, P., 2003. One is bobbing, for which these particular individuals bounce their bodies. Harvestmen (order Opiliones) are members of the class Arachnida, together with spiders, scorpions, pseudoscorpions, ticks and mites. 44, 76–82. While most species … 33, 55–66. Behav. [62], The interfamilial relationships within Opiliones are not yet fully resolved, although significant strides have been made in recent years to determine these relationships. [69], The 410-million-year-old Eophalangium sheari is known from two specimens, one a female, the other a male. Several Opiliones in Argentina appear to be vulnerable, if not endangered. [2], Harvestmen are ancient arachnids. [21][41], Multiple species within the Laniatores and Dyspnoi possess stridulating organs, which are used as intraspecific communication and have also been shown to be used as a second line of defense when restrained by a predator. All Bugs. They exude strongly odored secretions from their scent glands, called ozopores,[21][23][28][35][54] that act as a shield against predators; this is the most effective defense they use which creates a strong and unpleasant taste. [21][24] Many species have also been able to camouflage their bodies by covering with secretions and debris from the leaf litter found in their environments. Arachnol. Some harvestmen have elaborate and brightly colored patterns or appendages which contrast with the body coloration, potentially serving as an aposematic warning to potential predators. Arachnids Photo by Gilles San Martin. The harvestman is very distinctive with a round, compact body and extremely long legs. Although it looks like a long-legged spider, it isn’t one. Eyes in Cyphophthalmi, when present, are located laterally, near the ozopores. Can. The name "harvestman" is derived from the fact that the animals are most often seen in late summer and early fall during the harvest season. Nat. [3][4] While the two described Nemastomoides species are currently grouped as Dyspnoi, they look more like Eupnoi. [11], The females lay eggs from an ovipositor shortly after mating to several months later. J. Arachnol. Observations on the defensive behaviors of a Neotropical Gonyleptidae (Arachnida, Opiliones). Well-preserved fossils have been found in the 400-million-year-old Rhynie cherts of Scotland, and 305-million-year-old rocks in France, which look surprisingly modern, indicating that their basic body shape developed very early on,[4] and, at least in some taxa, has changed little since that time. A pair of spiracles is located between the base of the fourth pair of legs and the abdomen, with one opening on each side. J. Arachnol. Lines of defense in the harvestman Hoplobunus mexicanus (Arachnida: Opiliones): Aposematism, stridulation, thanatosis, and irritant chemicals. Gnaspini, P., Rodrigues, G.S., 2011. Ecol. They can be easily distinguished from long-legged spiders by their fused body regions and single pair of eyes in the middle of the cephalothorax. Syst. None of the known species of harvestmen has venom glands; their chelicerae are not hollowed fangs but grasping claws that are typically very small and not strong enough to break human skin. 91, 726–731. The Biology of Wetas, King Crickets and Their Allies. It is one of the Opilones, a group of arachnids closely related to spiders. If they are caught, they are able to shed a leg to escape. Scientific name: Opiliones Size: Body 5 to 8mm. The order Opiliones includes five suborders: Cyphophthalmi, Eupnoi, Dyspnoi, Laniatores, and Tetrophthalmi, which were named in 2014. Guffey, C., 1998. It has been suggested that this may be related to the Ortholasmatinae (Nemastomatidae).[71]. The order Opiliones contains five suborders. Despite being similar in appearance to, and often confused with, spiders, they are probably closely related to the scorpions, pseudoscorpions, and solifuges; these four orders form the clade Dromopoda. Both are from caves in central Texas. [21][25] Some hard-bodied harvestmen have epizoic cyanobacteria and liverworts growing on their bodies that suggest potential benefits for camouflage against large backgrounds to avoid detection by diurnal predators.[26][27]. Biochem. More than 20 fossil species are known from the Cenozoic, three from the Mesozoic,[61] and at least seven from the Paleozoic. Some are scavengers, feeding upon dead organisms, bird dung, and other fecal material. Edgar, A.L., 1971. Scientific name: Phalangium opilio The Common harvestman is familiar to us as the large, spindly spider-like creature that frequents gardens and houses. Beetles. Carl Friedrich Roewer described about a third (2,260) of today's known species from the 1910s to the 1950s, and published the landmark systematic work Die Weberknechte der Erde (Harvestmen of the World) in 1923, with descriptions of all species known to that time. Secretions of Opilionids, Whip Scorpions and Pseudoscorpions, in: Arthropod Venoms, Handbook of Experimental Pharmacology / Handbuch Der Experimentellen Pharmakologie. 75, 905–918. Spiders have a distinct abdomen that is separated from the cephalothorax by a constriction, and they have three to four pairs of eyes, usually around the margins of the cephalothorax. González, A., Rossini, C., Eisner, T., 2004. L. Koch, Tord Tamerlan Teodor Thorell (1860s-1870s) Following the floods this winter, watch how one area is using nature as a natural protector. Thanatosis as an adaptive male mating strategy in the nuptial gift–giving spider Pisaura mirabilis. Biological Reviews. [22] Darker colorations and patterns function as camouflage when they remain motionless. The stomotheca is formed by extensions of the coxae of the pedipalps and the first pair of legs. Gregarious behavior is likely a strategy against climatic odds, but also against predators, combining the effect of scent secretions, and reducing the probability of any particular individual being eaten.[2]. Maiorerus randoi has only been found in one cave in the Canary Islands. Mimicry: imitative depiction of discharged defensive secretion on carapace of an opilionid. So far, they are also absent from the Lower Cretaceous Crato Formation of Brazil, a Lagerstätte that has yielded many other terrestrial arachnids. Together with the 305-million-year-old Hastocularis argus, it forms the suborder Tetrophthalmi.[3][70]. CHEMOECOLOGY 14, 5–7. Common Name: Harvestman The harvestmen most frequently seen are species of Opilio, Odiellus and Leiobunum that live in hedgerows, parks and gardens amongst rough vegetation or on tree trunks, walls and fences. [51] These secretions have successfully protected the harvestmen against wandering spiders (Ctenidae),[15][16] wolf spiders (Lycosidae) and Formica exsectoides ants. It is included in the Catálogo Nacional de especies amenazadas (National catalog of threatened species) from the Spanish government. Markings on legs can cause an interruption of the leg outline and loss of leg proportion recognition. A recent molecular study of Opiliones, however, dated the origin of the order at about 473 million years ago (Mya), during the Ordovician.[68]. Mass. [12] Depending on circumstances such as temperature, the eggs may hatch at any time after the first 20 days, up to about half a year after being laid. J. Arachnol. 87–99. The group includes more than 6,300 species. When attacked, harvestmen are able to shed a leg as a defensive trick. Fossils from the Devonian Rhynie chert, 410 million years ago, already show characteristics like tracheae and sexual organs, indicating that the group has lived on land since that time. [2] The order Opiliones includes five suborders: Cyphophthalmi, Eupnoi, Dyspnoi, Laniatores, and Tetrophthalmi, which were named in 2014.[3]. Harvestmen are also referred to as "shepherd spiders" in reference to how their unusually long legs reminded observers of the ways that some European shepherds used stilts to better observe their wandering flocks from a distance.[6]. A male Opilio canestrinii cleaning one of his legs by drawing it through his jaws. Daddy longlegs, (order Opiliones), also spelled daddy-longlegs or daddy long legs, also called harvestman, any of more than 6,000 species of arachnids (class Arachnida) that are known for their extremely long and thin legs and for their compact bodies. Most Opiliones, except for Cyphophthalmi, have a single pair of eyes in the middle of the head, oriented sideways. [15] Also this has been proven to increase survival against recluse spiders by causing injury, allowing the harvestman to escape from predation. These pacemakers send signals via the nerves to the muscles to extend the leg and then the leg relaxes between signals. They are also commonly found on structures, tree trunks or climbing garden vegetation. 36, 369–376. It is a copy of Hil Videos (YouTube) Harvestman (Leiobunum spp.) Hansen, L.S., Gonzales, S.F., Toft, S., Bilde, T., 2008. Harvestmen of Britain and Ireland An interactive guide from the Field Studies Council. Mating involves direct copulation, rather than the deposition of a spermatophore. Perder la cola o la vida. They do not have book lungs, and breathe through tracheae. Welcome! Behavioral repertory of the neotropical harvestman ilhaia cuspidata (opiliones, gonyleptidae). They are visible during this season because it's generally the time when they mate. Butterflies & Moths. Studies on the biology and ecology of Michigan Phalangida (Opiliones). Nature is an adventure waiting to be had. This makes them some of the oldest animals on Earth. This fantastic wetland site is located north of Southport town centre and has some of the best wildlife in the region. It has been shown to be successful against ants and spiders. Comparative study of the defensive behavior and morphology of the gland opening area among harvestmen (Arachnida, Opiliones, Gonyleptidae) under a phylogenetic perspective. Roth, V.D., Roth, B.M., 1984. review of appendotomy in spiders and other arachnids. 207076, Scotland no. Neurophysiol. Some animals respond to attacks by simulating an apparent death to avoid either detection or further attacks. Scientific name: order: opiliones . The female bears an ovipositor and is about 10 mm (0.39 in) long, whilst the male had a discernable penis. [50] This is also seen when disturbing an aggregation of multiple individuals, where they all scatter. Macias-Ordonez, R., 1998. Representatives of each extant suborder can be found on all continents except Antarctica. Catch up with the RSPB’s own nature detectives on the case as they look to save some very special places. Gonzalo Giribet, Adriano Brilhante Kury, Tone Novak (21st century). Pereira, W., Elpino-Campos, A., Del-Claro, K., Machado, G., 2004. Mites are small, generally parasitic arachnids very closely related to ticks. Some such Opiliones only have this shield in the males. 32, 22–30. CABI. Evidence of circadian rhythm in antipredator behaviour in the orb-weaving spider Larinioides cornutus. Cokendolpher, J.C., 1987. [21][53] By pinching with their chelicerae and pedipalps, they can cause harm to a potential predator. It predates on smaller invertebrates which it catches using hooks on the ends of its legs. This is believed to entice the female into mating a second time. Defences of a Neotropical harvestman against different levels of threat by the recluse spider. Scientific name: Opiliones. Because their eyes cannot form images, they use their second pair of legs as antennae to explore their environment. Primary defenses help the harvestmen avoid encountering a potential predator, and include crypsis, aposematism, and mimicry. They have a gonopore on the ventral cephalothorax, and the copulation is direct as male Opiliones have a penis, unlike other arachnids. The abdomen is distinctly segmented and the two eyes are mounted on a large dorsal tubercle on the top surface of the body (carapace). This distracts the predator while the harvestman makes its escape. Eugène Simon, William Sørensen (1880s-1890s) Unlike the spiders, it has no silk glands so is not able to spin a web. Holmberg, R.G., Angerilli, N.P.D., LaCasse, L.J., 1984. Predators of harvestmen include a variety of animals, including some mammals,[13][14] amphibians, and other arachnids like spiders[15][16] and scorpions. R. Soc. There are some 30 different species of harvestmen (Opiliones) in the UK. Unlike most other arachnids, harvestmen do not have a sucking stomach or a filtering mechanism. Courtship, copulation, and genital mechanics in Physocyclus globosus (Araneae, Pholcidae). 82, 549–555. Harvest. Anim. As in all Arachnida, the body in the Opiliones has two tagmata, the anterior cephalothorax or prosoma, and the posterior 10-segmented abdomen or opisthosoma. 72, 22. [citation needed], A fossil of Halitherses grimaldii, a long-legged Dyspnoi with large eyes, was found in Burmese amber dating from approximately 100 Mya. Spotted at Thomson Nature Park – January 2021 Machado, G., Pomini, A.M., 2008. The family Stygophalangiidae (one species, Stygophalangium karamani) from underground waters in North Macedonia is sometimes misplaced in the Phalangioidea. Most hunting harvestmen ambush their prey, although active hunting is also found. A new species of pseudotrogulus roewer and assignment of the genus to the hernandariinae (opiliones, gonyleptidae). Segovia, J.M.G., Del-Claro, K., Willemart, R.H., 2015. J. Arachnol. Harvestmen (Opiliones) are a group of arachnids known for their long, delicate legs and their oval body. Pomini, A.M., Machado, G., Pinto-da-Rocha, R., Macías-Ordóñez, R., Marsaioli, A.J., 2010. A 305-million-year-old fossilized harvestman with two pairs of eyes was reported in 2014. 26, 296–302. Harvestmen have adapted to a variety of lifestyles from troglobitic and epigeic to rock dwelling and a few fully arboreal species. While some harvestman's legs twitch for a minute, others have been recorded to twitch up to an hour. Losing legs and walking hard: effects of autotomy and different substrates in the locomotion of harvestmen in the genus Prionostemma. Other differences include the fact that Opiliones have no venom glands in their chelicerae, so pose no danger to humans. 12, 195–204. Houghton, J.E., Townsend, V.R., Proud, D.N., 2011. Beetles. 30, 173–176. Humphreys, R.K., Ruxton, G.D., 2018. Syst. Description: Harvestmen have a globular body. In some species, the fluid contains noxious quinones. [15][51][52] Many have spines on their pedipalps, back legs, or bodies. See our ideas to keep you connected to nature during coronavirus, From our regular emails to your favourite social media, there’s more than one way to keep in touch with nature. They can be found on the soil surface, and under rocks or mulch. Particular patterns or color markings on harvestmen's bodies can reduce detection by disrupting the animals' outlines or providing camouflage. Whether both specimens belong to the same species is not definitely known. Morphology and functional anatomy. Some species build nests for this purpose. What do harvestmen look like? The reserve has seen more than thirty species of wading birds. So far, no harvestman has been included in any kind of a Red List in Argentina, so they receive no protection. The defense system of fear: behavior and neurocircuitry. Field, L.H., Glasgow, S., 2001. Leave it all behind: a taxonomic perspective of autotomy in invertebrates. The twitching has been hypothesized to function as an evolutionary advantage by keeping the attention of a predator while the harvestman escapes.[2]. All troglobitic species (of all animal taxa) are considered to be at least threatened in Brazil. Although it looks like a long-legged spider, it isn’t one. 26, 81–90. [28] Mimicry (Müllerian mimicry) occurring between Brazilian harvestmen that resemble others could be explained by convergent evolution.[21]. Fossil records show that harvestmen have been around for at least 400 million years, and they’ve remained largely unchanged during that time. It is also known as a daddy longlegs. "A Paleozoic Stem Group to Mite Harvestmen Revealed through Integration of Phylogenetics and Development", "Anatomically modern Carboniferous harvestmen demonstrate early cladogenesis and stasis in Opiliones", 4-Eyed Daddy Longlegs Helps Explain Arachnid Evolution, "Third species of Guasiniidae (Opiliones, Laniatores) with comments on familial relationships", "Determining the fitness consequences of antipredation behavior", "Harvestmen (Arachnida: Opiliones) from the Middle Jurassic of China", "Evolutionary and biogeographical history of an ancient and global group of arachnids (Arachnida: Opiliones: Cyphophthalmi) with a new taxonomic arrangement", https://dx.doi.org/10.1098/rspb.2016.2340, "World Checklist of Opiliones species (Arachnida). J. Zool. [2], Although parthenogenetic species do occur, most harvestmen reproduce sexually. Naturally, most finds are from comparatively recent times. They have long legs, tracheae, and no median eyes. Epizoic cyanobacteria associated with a Neotropical harvestman (Opiliones: Sclerosomatidae) from Costa Rica. [20] However, these chemical irritants are not able to prevent four species of harvestmen being preyed upon by the black scorpion Bothriurus bonariensis (Bothriuridae). All species lay eggs. Get out, get busy and get wild! Characteristics, Scientific Name, Classification, Taxonomy, Territorial Claims, and pictures of the Eastern-Harvestman (North America) ☰ MENU ☰ MENU × BugFinder. Description of new taxa has always been dependent on the activity of a few dedicated taxonomists. Chemical defenses in the opilionid infraorder Insidiatores: divergence in chemical defenses between Triaenonychidae and Travunioidea and within travunioid harvestmen (Opiliones) from eastern and western North America | Journal of Arachnology. The species has been introduced to North America, North Africa and New Zealand. It predates on smaller invertebrates … Sociobiol. Zoology 116, 168–174. Even after the leg becomes detached from the body it continues to jump and flick about. The harvestman has a small, rounded body with long spindly legs. Some Gonyleptidae individuals that produce translucid secretions have orange markings on their carapaces. The effectiveness of post-contact defenses in a prey with no pre-contact detection. The Opiliones (formerly Phalangida) are an order of arachnids colloquially known as harvestmen, harvesters, or daddy longlegs. Harvestmen have a pair of prosomatic defensive scent glands (ozopores) that secrete a peculiar-smelling fluid when disturbed. In more active species, spiracles are also found upon the tibia of the legs. Chelini, M.-C., Willemart, R.H., Hebets, E.A., 2009. Predators: birds, reptiles, amphibians. Characteristics, Scientific Name, Classification, Taxonomy, Territorial Claims, and pictures of the Harvestman (North America) ☰ MENU ☰ MENU × BugFinder. Daily activity schedule, gregariousness, and defensive behaviour in the Neotropical harvestman Goniosoma longipes (Opiliones: Gonyleptidae): Journal of Natural History: Vol 34, No 4. In. Costs and benefits of freezing behaviour in the harvestman Eumesosoma roeweri (Arachnida, Opiliones). Brigantibunum listoni from East Kirkton near Edinburgh in Scotland is almost 340 million years old. [59] This is untrue on several counts. [33][34][35][36], Freezing – or the complete halt of movement – has been documented in the family Sclerosomatidae. [42], Autotomy is the voluntary amputation of an appendage, and is employed to escape when restrained by a predator. 38, 300–308. The following list is a compilation of interfamilial relationships recovered from several recent phylogenetic studies, although the placement and even monophyly of several taxa are still in question.[63][64][65][66][67]. [21][38][39][40] This can be a deceiving mechanism to avoid predation when they are in a large aggregation of individuals, which are all trembling at the same time. Typical body length does not exceed 7 mm (0.28 in), and some species are smaller than 1 mm, although the largest known species, Trogulus torosus (Trogulidae), grows as long as 22 mm (0.87 in). Phalangium opilio From Wikipedia, the free encyclopedia Phalangium opilio is "the most widespread species of harvestman in the world", occurring natively in Europe, and much of Asia. Since the 1990s, study of the biology and ecology of harvestmen has intensified, especially in South America. The Opiliones are known for having exceptionally long legs relative to their body size; however, some species are short-legged. As of April 2017[update], over 6,650 species of harvestmen have been discovered worldwide,[1] although the total number of extant species may exceed 10,000. Overwintering Aggregations of Leiobunum paessleri in Caves and Mines (Arachnida, Opiliones). Behav. Southeast. Its head and body are fused together and are light chestnut in colour. Insects by State. While the presence of harvestmen is not likely to completely suppress pest populations, they do contribute to biological control. Neurophysiol. Insects by State. Scientific name: Opiliones. Harvestmen are beneficial predators in the garden and very common in residential landscapes. Revue Arachnologique, 7, pp.59-63. Unless otherwise noted, all species are from the Eocene. Some of them are divided medially on the surface to form two plates beside each other. Jones, T.C., Akoury, T.S., Hauser, C.K., Moore, D., 2011. Proc. Fernández R, Sharma PP, Tourinho AL, Giribet G. 2017 The Opiliones tree of life: shedding light on harvestmen relationships through transcriptomics. Huber, B.A., Eberhard, W.G., 1997. Firmo, C., Pinto-da-Rocha, R., 2002. J. Arachnol. Harvestmen clean their legs after eating by drawing each leg in turn through their jaws. It does not have fangs and does not produce venom. Bull.-Br. Leg Autotomy and Its Potential Fitness Costs for Two Species of Harvestmen (Arachnida, Opiliones). Some fossils from the Permian are possibly harvestmen, but these are not well preserved. In some highly derived species, the first five abdominal segments are fused into a dorsal shield called the scutum, which in most such species is fused with the carapace. Machado, G., Raimundo, R.L.G., Oliveira, P.S., 2000. The Opiliones are an order of arachnids colloquially known as harvestmen, harvesters, or daddy longlegs. Processes 82, 153–159. J. Arachnol. 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. This interactive guide is a resource for anyone who wants to identify a harvestman and/or learn about the features that can be used to separate the different taxa in the field. Misslin, R., 2003. Secret Weapons: Defenses of Insects, Spiders, Scorpions, and Other Many-legged Creatures. Ecol. Springer, Berlin, Heidelberg, pp. Habitat: woodland, gardens, rural areas. An urban legend claims that the harvestman is the most venomous animal in the world,[58] but possesses fangs too short or a mouth too round and small to bite a human, rendering it harmless (the same myth applies to Pholcus phalangioides and the cranefly, which are both also called a "daddy longlegs"). The second pair of legs is longer than the others and function as antennae or feelers. Kustarachne tenuipes was shown in 2004 to be a harvestman, after residing for almost one hundred years in its own arachnid order, the "Kustarachnida". [23] Within the genus Leiobunum are multiple species with cryptic coloration that changes over ontogeny to match the microhabitat used at each life stage. [21][41] Cellar spiders (Pholcidae) that are commonly mistaken for daddy long-legs (Opiliones) also exhibit this behavior when their webs are disturbed or even during courtship. Like all arachnids, harvestmen have four pairs of walking legs, a pair of chelicerae, and a pair of small, leg-like appendages called pedipalps. All are moderately large, the body up to about 10 mm long, and more or less brownish in colour. Scientific name: Leiobunum rotundum. We spend 90% of net income on conservation, public education and advocacy, The RSPB is a member of BirdLife International. Biol. This checklist details the accepted scientific names, authorities, synonymy and higher taxonomy for harvestmen (Arachnida: Order Opiliones) that have been recorded from the British Isles.