Opiliones
Encyclopedia
Opiliones are an order of arachnid
s commonly known as harvestmen. , over 6,400 species of harvestmen have been discovered worldwide, although the real number of extant species may exceed 10,000. The order Opiliones can be divided into four suborders: Cyphophthalmi
, Eupnoi
, Dyspnoi
and Laniatores
. Well-preserved fossils have been found in the 400-million-year-old Rhynie chert
s of Scotland, which look surprisingly modern, indicating that the basic structure of the harvestmen has not changed much since then. Phylogenetic position is disputed: their closest relatives may be the mites (Acari) or the Novogenuata (the Scorpiones, Pseudoscorpiones and Solifugae
).
Although they belong to the class of arachnids, harvestmen are not spider
s, which are of the order Araneae rather than the order Opiliones.
In some places, harvestmen are known by the name "daddy longlegs" or "granddaddy longlegs", but this name is also used for two other unrelated arthropods: the crane fly
(Tipulidae) and the cellar spider (Pholcidae).
These arachnids are known for their exceptionally long walking legs, compared to body size, although there are also short-legged species. The difference between harvestmen and spiders is that in harvestmen the two main body sections (the abdomen
with ten segments and cephalothorax
, or prosoma and opisthosoma
) are broadly joined, so that they appear to be one oval
structure; they also have no venom
or silk glands. In more advanced species, the first five abdominal segments are often fused into a dorsal shield called the scutum
, which is normally fused with the carapace
. Sometimes this shield is only present in males. The two most posterior abdominal segments can be reduced or separated in the middle on the surface to form two plates lying next to each other. The second pair of legs are longer than the others and work as antennae
. This can be hard to see in short-legged species.
The feeding apparatus (stomotheca
) differs from other arachnids in that ingestion is not restricted to liquid, but chunks of food can be taken in. The stomotheca is formed by extensions from the pedipalp
s and the first pair of legs.
They have a single pair of eyes in the middle of their heads, oriented sideways. However, there are eyeless species, such as the Brazilian Caecobunus termitarum (Grassatores
) from termite
nests, Giupponia chagasi (Gonyleptidae
) from caves, and all species of Guasiniidae
.
Harvestmen have a pair of prosomatic defensive scent gland
s (ozopore
s) that secrete a peculiar smelling fluid when disturbed, confirmed in some species to contain noxious quinones
. Harvestmen do not have silk glands
and do not possess venom glands
, posing absolutely no danger to humans (see below). They do not have book lungs, and breathe through tracheae
only. Between the base of the fourth pair of legs and the abdomen a pair of spiracles are located, one opening on each side. In more active species, spiracles are also found upon the tibia
of the legs. They have a gonopore
on the ventral cephalothorax, and the copulation is direct as the male has a penis (while the female has an ovipositor
). All species lay eggs
.
The legs continue to twitch after they are detached. This is because there are 'pacemakers' located in the ends of the first long segment (femur) of their legs. These pacemakers send signals via the nerves to the muscles to extend the leg and then the leg relaxes between signals. While some harvestman's legs will twitch for a minute, other kinds have been recorded to twitch for up to an hour. The twitching has been hypothesized as a means to keep the attention of a predator while the harvestman escapes.
Typical body length does not exceed 7 millimetre (0.275590551181102 in), with some species smaller than one mm, although the largest species Trogulus torosus (Trogulidae
) can reach a length of 22 millimetre (0.866141732283465 in). However, leg span is much larger and can exceed 160 millimetres (6.3 in). Most species live for a year.
Many species are omnivorous, eating primarily small insect
s and all kinds of plant material and fungi; some are scavenger
s, feeding upon dead organisms, bird dung and other fecal
material. This broad range is quite unusual in arachnids, which are usually pure predators. Most hunting harvestmen ambush their prey, although active hunting is also found. Because their eyes cannot form images, they use their second pair of legs as antennae to explore their environment. Unlike most other arachnids, harvestmen do not have a sucking stomach or a filtering mechanism. Rather, they ingest small particles of their food, thus making them vulnerable to internal parasites such as gregarines.
Although parthenogenetic
species do occur, most harvestmen reproduce sexually
. Mating
involves direct copulation, rather than the deposition of a spermatophore
. The males of some species offer a secretion from their chelicerae
to the female before copulation. Sometimes the male guards the female after copulation and, in many species, the males defend territories. The females lay eggs shortly after mating or anytime up to several months later. Some species build nests for this purpose. A unique feature of harvestmen is that in some species the male is solely responsible for guarding the eggs resulting from multiple partners, often against egg-eating females, and subjecting the eggs to regular cleaning. The eggs can hatch anytime after the first 20 days, up to almost half a year after being laid. Harvestmen need from four to eight nymphal stages to reach maturity, with six the most common.
They are mostly nocturnal and colored in hues of brown, although there are a number of diurnal
species which have vivid patterns in yellow, green and black with varied reddish and blackish mottling and reticulation.
To deal with predators such as birds, mammals, amphibians and spiders, some species glue debris onto their body, while many play dead when disturbed. Many species can detach their legs, which keep on moving, to confuse predators. Especially long-legged species vibrate their body ("bobbing"), probably also to confuse predators. This is similar to the behavior of the similar looking but unrelated cellar spider
, which vibrates wildly in its web when touched. Scent glands emit substances that can deter larger predators, but are also effective against ant
s.
Many species of harvestmen easily tolerate members of their own species, with aggregations of many individuals often found at protected sites near water. These aggregations can count up to 200 animals in the Laniatores
, but more than 70,000 in certain Eupnoi
. This behavior is likely a strategy against climatic odds, but also against predators, combining the effect of scent secretions, and reducing the probability of each individual of being eaten.
. There are four species of Opiliones in the Brazilian National List for endangered species, all of them cave-dwelling species. Giupponia chagasi, Iandumoema uai, Pachylospeleus strinatii and Spaeleoleptes spaeleus.
Several Opiliones in Argentina appear to be vulnerable, if not endangered. These include Pachyloidellus fulvigranulatus, which is found only on top of Cerro Uritorco, the highest peak in the Sierras Chicas chain (provincia de Cordoba) and Pachyloides borellii is in rainforest patches in North West Argentina which are in an area being dramatically destroyed by humans. The cave living Picunchenops spelaeus is apparently endangered through human action. So far no harvestman has been included in any kind of a Red List in Argentina and therefore they receive no protection.
Maiorerus randoi has only been found in one cave in the Canary Islands
. It is included in the Catálogo Nacional de especies amenazadas (National catalog of threatened species) from the Spanish
government.
Texella reddelli
and Texella reyesi
are listed as endangered species in the USA. Both are from caves in central Texas
. Texella cokendolpheri
from a cave in central Texas and Calicina minor, Microcina edgewoodensis, Microcina homi, Microcina jungi, Microcina leei, Microcina lumi, and Microcina tiburona from around springs and other restricted habitats of central California
are being considered for listing as endangered species, but as yet receive no protection.
An urban legend
claims that the harvestman is the most venom
ous animal in the world, but possesses fangs too short or a mouth too round and small to bite a human and therefore is not dangerous (the same myth applies to Pholcus phalangioides
and the cranefly, which are both also called a 'daddy longlegs'). This is untrue on several counts. None of the known species of harvestmen have venom glands; their chelicerae
are not hollowed fangs but grasping claws that are typically very small and definitely not strong enough to break human skin. This myth is so pervasive that it was debunked by two popular television shows, MythBusters
and Bill Nye The Science Guy
.
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. Other important taxonomists in this field include Eugène Simon
, Tord Tamerlan Teodor Thorell, William Sørensen and Zac Jewell and also Heinrick VanStratunburgs around the turn of the 20th century, and later Cândido Firmino de Mello-Leitão
and Reginald Frederick Lawrence. Since 1980, study of the biology and ecology of harvestmen has intensified, especially in South America
.
s. Fossils from the Devonian
Rhynie chert
, 410 million years ago, already show characteristics like tracheae and sexual organs, proving that the group has lived on land since that time. They are probably closely related to the scorpion
s, pseudoscorpion
s and solifuges; these four orders form the clade Dromopoda
. The Opiliones have remained almost unchanged morphologically over a long period. Indeed, one species discovered in China, fossilized by fine grained volcanic ash around 165 million years ago, is hardly discernible from its modern day descendant and belongs to an existing family of harvestman.
(1801–1875) honored the naturalist Martin Lister
(1638–1712) by adopting his term Opiliones for this order; Lister taxonomically described three species from England, United Kingdom.
The family Stygophalangiidae (1 species, Stygophalangium karamani
) from underground waters in Macedonia
is sometimes misplaced in the Phalangioidea. It is not a harvestman.
.
The oldest known harvestman, from the 400 million years old Devonian
Rhynie chert
, already has almost all the characteristics of modern species, placing the origin of harvestmen in the Silurian
, or even earlier.
Interestingly, no fossils of Cyphophthalmi
or Laniatores
much older than 50 million years are known, despite the former presenting a basal clade, and the latter having probably diverged from the Dyspnoi more than 300 million years ago.
Naturally, most finds are from comparatively recent times, but it is interesting that while there are more than 20 known species from the Cenozoic
, and at least seven from the Paleozoic
, only one species from the Mesozoic
has yet been found.
and is about 10 millimetre (0.393700787401575 in) long, the male penis can be discerned too. It is not definitely known if both sexes belong to the same species. They have long legs, tracheae
, and no median eyes.
Brigantibunum listoni from East Kirkton near Edinburgh
in Scotland is almost 340 million years old. Its placement is rather uncertain, apart from it being a harvestman.
From about 300 million years ago (mya) there are several finds from the Coal Measures
of North America
and Europe
. While the two described Nemastomoides species are currently grouped as Dyspnoi, they look more like Eupnoi.
Kustarachne tenuipes was shown in 2004 to be a harvestman, after residing for almost hundred years in its own arachnid order, the "Kustarachnida".
There are some fossils from the Permian
that are possibly harvestmen, but these are not well preserved.
. They are also so far absent from the Lower Cretaceous Crato Formation
of Brazil
, which has yielded many other terrestrial arachnids. An unnamed long-legged harvestman was reported from the Early Cretaceous of Koonwarra, Victoria
, Australia, which may be a Eupnoi.
Halitherses grimaldii from Burmese amber (c. ) is a long-legged Dyspnoi with large eyes, which may be related to the Ortholasmatinae (Nemastomatidae).
.
Arachnid
Arachnids are a class of joint-legged invertebrate animals in the subphylum Chelicerata. All arachnids have eight legs, although in some species the front pair may convert to a sensory function. The term is derived from the Greek words , meaning "spider".Almost all extant arachnids are terrestrial...
s commonly known as harvestmen. , over 6,400 species of harvestmen have been discovered worldwide, although the real number of extant species may exceed 10,000. The order Opiliones can be divided into four suborders: Cyphophthalmi
Cyphophthalmi
The Cyphophthalmi are a suborder of harvestmen, with about 36 genera, and more than hundred described species.The six families are currently grouped into two infraorders, the Tropicophthalmi and the Temperophthalmi; however, these are not supported by modern phylogenetic analysis.They are smaller...
, Eupnoi
Eupnoi
The Eupnoi are a suborder of harvestmen, with more than 200 genera, and about 1,700 described species.They consist of two superfamilies, the Phalangioidea with many long-legged species common to northern temperate regions, and the small group Caddoidea, which have prominent eyes and spiny...
, Dyspnoi
Dyspnoi
The Dyspnoi are a suborder of harvestmen, with about 32 genera, and about 320 described species.Several fossil species are known, including two extinct families.The superfamilies Ischyropsalidoidea and Troguloidea are monophyletic...
and Laniatores
Laniatores
Laniatores is the largest suborder of the arachnid order Opiliones with over 4,000 described species worldwide. The majority of the species are highly dependent on humid environments and usually correlated with tropical and temperate forest habitats....
. Well-preserved fossils have been found in the 400-million-year-old Rhynie chert
Rhynie chert
The Rhynie chert is an Early Devonian sedimentary deposit exhibiting extraordinary fossil detail or completeness . It is exposed near the village of Rhynie, Aberdeenshire, Scotland; a second unit, the Windyfield chert, is located some 700 m away...
s of Scotland, which look surprisingly modern, indicating that the basic structure of the harvestmen has not changed much since then. Phylogenetic position is disputed: their closest relatives may be the mites (Acari) or the Novogenuata (the Scorpiones, Pseudoscorpiones and Solifugae
Solifugae
Solifugae are an order of Arachnida, known as camel spiders, wind scorpions and sun spiders or solifuges, comprising more than 1,000 described species in about 153 genera...
).
Although they belong to the class of arachnids, harvestmen are not spider
Spider
Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...
s, which are of the order Araneae rather than the order Opiliones.
In some places, harvestmen are known by the name "daddy longlegs" or "granddaddy longlegs", but this name is also used for two other unrelated arthropods: the crane fly
Crane fly
A crane fly is an insect in the family Tipulidae. Adults are very slender, long-legged flies that may vary in length from though tropical species may exceed to ....
(Tipulidae) and the cellar spider (Pholcidae).
Physical description
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
with ten segments and cephalothorax
Cephalothorax
The cephalothorax is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. The word cephalothorax is derived from the Greek words for head and thorax...
, or prosoma and opisthosoma
Opisthosoma
The opisthosoma is the posterior part of the body in some arthropods, behind the prosoma . It is a distinctive feature of the subphylum Chelicerata...
) are broadly joined, so that they appear to be one oval
Oval
An oval is any curve resembling an egg or an ellipse, such as a Cassini oval. The term does not have a precise mathematical definition except in one area oval , but it may also refer to:* A sporting arena of oval shape** a cricket field...
structure; they also have no venom
Venom
Venom is the general term referring to any variety of toxins used by certain types of animals that inject it into their victims by the means of a bite or a sting...
or silk glands. In more advanced species, the first five abdominal segments are often fused into a dorsal shield called the scutum
Scute
A scute or scutum is a bony external plate or scale, as on the shell of a turtle, the skin of crocodilians, the feet of some birds or the anterior portion of the mesonotum in insects.-Properties:...
, which is normally fused with the carapace
Carapace
A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
. Sometimes this shield is only present in males. The two most posterior abdominal segments can be reduced or separated in the middle on the surface to form two plates lying next to each other. The second pair of legs are longer than the others and work as antennae
Antenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....
. This can be hard to see in short-legged species.
The feeding apparatus (stomotheca
Stomotheca
Stomotheca is the term applied to the feeding apparatus in front of the mouth of harvestmen, and sometimes the related scorpions. Usually it consists of the epistome , two pairs of coxapophyses and often a labium....
) differs from other arachnids in that ingestion is not restricted to liquid, but chunks of food can be taken in. The stomotheca is formed by extensions from the pedipalp
Pedipalp
Pedipalps , are the second pair of appendages of the prosoma in the subphylum Chelicerata. They are traditionally thought to be homologous with mandibles in Crustacea and insects, although more recent studies Pedipalps (commonly shortened to palps or palpi), are the second pair of appendages of the...
s and the first pair of legs.
They have a single pair of eyes in the middle of their heads, oriented sideways. However, there are eyeless species, such as the Brazilian Caecobunus termitarum (Grassatores
Grassatores
Grassatores is the most diverse infraorder of the Laniatores. It includes over 3,500 species distributed mainly in the World Tropics...
) from termite
Termite
Termites are a group of eusocial insects that, until recently, were classified at the taxonomic rank of order Isoptera , but are now accepted as the epifamily Termitoidae, of the cockroach order Blattodea...
nests, Giupponia chagasi (Gonyleptidae
Gonyleptidae
Gonyleptidae is a Neotropical family of harvestmen with more than 800 species, the largest in the Suborder Laniatores and the second largest of the Opiiones as a whole...
) from caves, and all species of Guasiniidae
Guasiniidae
The Guasiniidae are a family of harvestman with three described species from South America.It is, together with the Fissiphalliidae and the Ogoveidae, one of the least diverse harvestman families....
.
Scent gland
Scent glands are found in the genital area of most mammals and in various other parts of the body, such as the underarms of humans and the preorbital glands of deer and muskox. They produce a semi-viscous fluid which contains pheromones. These odor-messengers indicate information such as status,...
s (ozopore
Ozopore
An ozopore is a defensive gland present in harvestmen, which are eight-legged arachnids also known as "daddy long-legs". These glands, also called "scent glands", "repugnatorial glands", "odoriferous glands" or "stink glands" by various authors, are located at the anterior sides of the prosoma.The...
s) that secrete a peculiar smelling fluid when disturbed, confirmed in some species to contain noxious quinones
1,4-Benzoquinone
1,4-Benzoquinone, commonly known as para-quinone, is a chemical compound with the formula C6H4O2. In a pure state, it forms bright-yellow crystals with a characteristic irritating odor, resembling that of chlorine, bleach, and hot plastic. Impure samples are often dark-colored due to the presence...
. Harvestmen do not have silk glands
Spider silk
Spider silk is a protein fiber spun by spiders. Spiders use their silk to make webs or other structures, which function as nets to catch other animals, or as nests or cocoons for protection for their offspring...
and do not possess venom glands
Spider bite
A spider bite is an injury resulting from the bites of spiders or other closely related arachnids.Spiders are active hunters and rely heavily on their bites to paralyze and kill their prey before consuming it. They also bite in self defense...
, posing absolutely no danger to humans (see below). They do not have book lungs, and breathe through tracheae
Invertebrate trachea
The invertebrate trachea refers to the open respiratory system composed of spiracles, tracheae, and tracheoles that terrestrial arthropods have to transport metabolic gases to and from tissues....
only. Between the base of the fourth pair of legs and the abdomen a pair of spiracles are located, one opening on each side. In more active species, spiracles are also found upon the tibia
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....
of the legs. They have a gonopore
Gonopore
A gonopore, sometimes called a gonadopore, is a genital pore in many invertebrates. Hexapods, including insects have a single common gonopore, except mayflies, which have a pair of gonopores...
on the ventral cephalothorax, and the copulation is direct as the male has a penis (while the female has an ovipositor
Ovipositor
The ovipositor is an organ used by some animals for oviposition, i.e., the laying of eggs. It consists of a maximum of three pairs of appendages formed to transmit the egg, to prepare a place for it, and to place it properly...
). All species lay eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
.
The legs continue to twitch after they are detached. This is because there are 'pacemakers' located in the ends of the first long segment (femur) of their legs. These pacemakers send signals via the nerves to the muscles to extend the leg and then the leg relaxes between signals. While some harvestman's legs will twitch for a minute, other kinds have been recorded to twitch for up to an hour. The twitching has been hypothesized as a means to keep the attention of a predator while the harvestman escapes.
Typical body length does not exceed 7 millimetre (0.275590551181102 in), with some species smaller than one mm, although the largest species Trogulus torosus (Trogulidae
Trogulidae
The Trogulidae are a family of harvestmen with about 45 known species.Members of this species have short legs and live in soil. They have dirt attached to their bodies, to escape predators. Their body length ranges from 2 to 22 mm. The body is in most genera somewhat flattened and leathery...
) can reach a length of 22 millimetre (0.866141732283465 in). However, leg span is much larger and can exceed 160 millimetres (6.3 in). Most species live for a year.
Behavior
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s and all kinds of plant material and fungi; some are scavenger
Scavenger
Scavenging is both a carnivorous and herbivorous feeding behavior in which individual scavengers search out dead animal and dead plant biomass on which to feed. The eating of carrion from the same species is referred to as cannibalism. Scavengers play an important role in the ecosystem by...
s, feeding upon dead organisms, bird dung and other fecal
Feces
Feces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...
material. This broad range is quite unusual in arachnids, which are usually pure predators. Most hunting harvestmen ambush their prey, although active hunting is also found. Because their eyes cannot form images, they use their second pair of legs as antennae to explore their environment. Unlike most other arachnids, harvestmen do not have a sucking stomach or a filtering mechanism. Rather, they ingest small particles of their food, thus making them vulnerable to internal parasites such as gregarines.
Parthenogenesis
Parthenogenesis is a form of asexual reproduction found in females, where growth and development of embryos occur without fertilization by a male...
species do occur, most harvestmen reproduce sexually
Sexual reproduction
Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. There are two main processes during sexual reproduction; they are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the...
. Mating
Mating
In biology, mating is the pairing of opposite-sex or hermaphroditic organisms for copulation. In social animals, it also includes the raising of their offspring. Copulation is the union of the sex organs of two sexually reproducing animals for insemination and subsequent internal fertilization...
involves direct copulation, rather than the deposition of a spermatophore
Spermatophore
A spermatophore or sperm ampulla is a capsule or mass created by males of various animal species, containing spermatozoa and transferred in entirety to the female's ovipore during copulation...
. The males of some species offer a secretion from their chelicerae
Chelicerae
The chelicerae are mouthparts of the Chelicerata, an arthropod subphylum that includes arachnids, Merostomata , and Pycnogonida . Chelicerae are pointed appendages which are used to grasp food, and are found in place of the chewing mandibles most other arthropods have...
to the female before copulation. Sometimes the male guards the female after copulation and, in many species, the males defend territories. The females lay eggs shortly after mating or anytime up to several months later. Some species build nests for this purpose. A unique feature of harvestmen is that in some species the male is solely responsible for guarding the eggs resulting from multiple partners, often against egg-eating females, and subjecting the eggs to regular cleaning. The eggs can hatch anytime after the first 20 days, up to almost half a year after being laid. Harvestmen need from four to eight nymphal stages to reach maturity, with six the most common.
They are mostly nocturnal and colored in hues of brown, although there are a number of diurnal
Diurnal animal
Diurnality is a plant or animal behavior characterized by activity during the day and sleeping at night.-In animals:Animals that are not diurnal might be nocturnal or crepuscular . Many animal species are diurnal, including many mammals, insects, reptiles and birds...
species which have vivid patterns in yellow, green and black with varied reddish and blackish mottling and reticulation.
To deal with predators such as birds, mammals, amphibians and spiders, some species glue debris onto their body, while many play dead when disturbed. Many species can detach their legs, which keep on moving, to confuse predators. Especially long-legged species vibrate their body ("bobbing"), probably also to confuse predators. This is similar to the behavior of the similar looking but unrelated cellar spider
Pholcus phalangioides
The cellar spider or daddy longlegs , also known as the skull spider due to its cephalothorax looking like a human skull, is a spider of the family Pholcidae. Females have a body length of about 9 mm; males are slightly smaller. Its legs are about 5 or 6 times the length of its body...
, which vibrates wildly in its web when touched. Scent glands emit substances that can deter larger predators, but are also effective against ant
Ant
Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...
s.
Many species of harvestmen easily tolerate members of their own species, with aggregations of many individuals often found at protected sites near water. These aggregations can count up to 200 animals in the Laniatores
Laniatores
Laniatores is the largest suborder of the arachnid order Opiliones with over 4,000 described species worldwide. The majority of the species are highly dependent on humid environments and usually correlated with tropical and temperate forest habitats....
, but more than 70,000 in certain Eupnoi
Eupnoi
The Eupnoi are a suborder of harvestmen, with more than 200 genera, and about 1,700 described species.They consist of two superfamilies, the Phalangioidea with many long-legged species common to northern temperate regions, and the small group Caddoidea, which have prominent eyes and spiny...
. This behavior is likely a strategy against climatic odds, but also against predators, combining the effect of scent secretions, and reducing the probability of each individual of being eaten.
Endangered status
All troglobitic species (of all animal taxa) are considered to be at least threatened in BrazilBrazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
. There are four species of Opiliones in the Brazilian National List for endangered species, all of them cave-dwelling species. Giupponia chagasi, Iandumoema uai, Pachylospeleus strinatii and Spaeleoleptes spaeleus.
Several Opiliones in Argentina appear to be vulnerable, if not endangered. These include Pachyloidellus fulvigranulatus, which is found only on top of Cerro Uritorco, the highest peak in the Sierras Chicas chain (provincia de Cordoba) and Pachyloides borellii is in rainforest patches in North West Argentina which are in an area being dramatically destroyed by humans. The cave living Picunchenops spelaeus is apparently endangered through human action. So far no harvestman has been included in any kind of a Red List in Argentina and therefore they receive no protection.
Maiorerus randoi has only been found in one cave in the Canary Islands
Canary Islands
The Canary Islands , also known as the Canaries , is a Spanish archipelago located just off the northwest coast of mainland Africa, 100 km west of the border between Morocco and the Western Sahara. The Canaries are a Spanish autonomous community and an outermost region of the European Union...
. It is included in the Catálogo Nacional de especies amenazadas (National catalog of threatened species) from the Spanish
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
government.
Texella reddelli
Texella reddelli
Texella reddelli, the Bee Creek cave harvestman, is a rare species of troglobitic harvestman that was added to the United States endangered species list in 1988, at the same time as six other species native to the karst ecosystem in Travis County and Williamson County, Texas, USA...
and Texella reyesi
Texella reyesi
Texella reyesi is a rare species of arachnid known by the common name Bone Cave harvestman. It is endemic to Texas in the United States, where it lives in subterranean limestone caves in Travis and Williamson Counties. It is threatened by the loss of its habitat...
are listed as endangered species in the USA. Both are from caves in central Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
. Texella cokendolpheri
Texella cokendolpheri
Texella cokendolpheri is a rare species of arachnid known by the common name Cokendolpher Cave harvestman. It may also be called the Robber Baron cave harvestman. It is endemic to Texas in the United States, where it is only known from a single cave in Bexar County...
from a cave in central Texas and Calicina minor, Microcina edgewoodensis, Microcina homi, Microcina jungi, Microcina leei, Microcina lumi, and Microcina tiburona from around springs and other restricted habitats of central California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
are being considered for listing as endangered species, but as yet receive no protection.
Misconception
Urban legend
An urban legend, urban myth, urban tale, or contemporary legend, is a form of modern folklore consisting of stories that may or may not have been believed by their tellers to be true...
claims that the harvestman is the most venom
Venom
Venom is the general term referring to any variety of toxins used by certain types of animals that inject it into their victims by the means of a bite or a sting...
ous animal in the world, but possesses fangs too short or a mouth too round and small to bite a human and therefore is not dangerous (the same myth applies to Pholcus phalangioides
Pholcus phalangioides
The cellar spider or daddy longlegs , also known as the skull spider due to its cephalothorax looking like a human skull, is a spider of the family Pholcidae. Females have a body length of about 9 mm; males are slightly smaller. Its legs are about 5 or 6 times the length of its body...
and the cranefly, which are both also called a 'daddy longlegs'). This is untrue on several counts. None of the known species of harvestmen have venom glands; their chelicerae
Chelicerae
The chelicerae are mouthparts of the Chelicerata, an arthropod subphylum that includes arachnids, Merostomata , and Pycnogonida . Chelicerae are pointed appendages which are used to grasp food, and are found in place of the chewing mandibles most other arthropods have...
are not hollowed fangs but grasping claws that are typically very small and definitely not strong enough to break human skin. This myth is so pervasive that it was debunked by two popular television shows, MythBusters
MythBusters
MythBusters is a science entertainment TV program created and produced by Beyond Television Productions for the Discovery Channel. The series is screened by numerous international broadcasters, including Discovery Channel Australia, Discovery Channel Latin America, Discovery Channel Canada, Quest...
and Bill Nye The Science Guy
Bill Nye the Science Guy
Bill Nye the Science Guy is an educational television program that originally aired from September 10, 1993 to June 20, 1998, hosted by Bill Nye and produced by Buena Vista Television. The show aired on PBS Kids and was also syndicated to local stations, making it the second first-run television...
.
Research
Harvestmen are a scientifically neglected group. Description of new taxa has always been dependent on the activity of a few dedicated taxonomists. Carl Friedrich RoewerCarl Friedrich Roewer
Carl Friedrich Roewer was a German arachnologist. He concentrated on harvestmen, where he described almost a third of today's known species, but also almost 700 taxa of spiders and numerous Solifugae....
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. Other important taxonomists in this field include Eugène Simon
Eugène Simon
Eugène Simon was a French arachnologist. His many taxonomic contributions include categorizing and naming many spiders, as well as creating genera such as Anelosimus, Psellocoptus and Phlogius....
, Tord Tamerlan Teodor Thorell, William Sørensen and Zac Jewell and also Heinrick VanStratunburgs around the turn of the 20th century, and later Cândido Firmino de Mello-Leitão
Cândido Firmino de Mello-Leitão
Cândido Firmino de Mello-Leitão, , was a Brazilian zoologist who is considered the founder of Arachnology in South America, publishing 198 papers on the taxonomy of Arachnida...
and Reginald Frederick Lawrence. Since 1980, study of the biology and ecology of harvestmen has intensified, especially in South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
.
Phylogeny
Harvestmen are very old arachnidArachnid
Arachnids are a class of joint-legged invertebrate animals in the subphylum Chelicerata. All arachnids have eight legs, although in some species the front pair may convert to a sensory function. The term is derived from the Greek words , meaning "spider".Almost all extant arachnids are terrestrial...
s. Fossils from the Devonian
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
Rhynie chert
Rhynie chert
The Rhynie chert is an Early Devonian sedimentary deposit exhibiting extraordinary fossil detail or completeness . It is exposed near the village of Rhynie, Aberdeenshire, Scotland; a second unit, the Windyfield chert, is located some 700 m away...
, 410 million years ago, already show characteristics like tracheae and sexual organs, proving that the group has lived on land since that time. They are probably closely related to the scorpion
Scorpion
Scorpions are predatory arthropod animals of the order Scorpiones within the class Arachnida. They have eight legs and are easily recognized by the pair of grasping claws and the narrow, segmented tail, often carried in a characteristic forward curve over the back, ending with a venomous stinger...
s, pseudoscorpion
Pseudoscorpion
A pseudoscorpion, , is an arachnid belonging to the order Pseudoscorpionida, also known as Pseudoscorpiones or Chelonethida....
s and solifuges; these four orders form the clade Dromopoda
Dromopoda
Dromopoda is a subclass of the arachnids, including the Opiliones , Scorpions, Pseudoscorpions and Solifugae . The latter three are sometimes grouped as Novogenuata. However, morphological analysis showed the Dromopoda to be monophylic only when fossils were not taken into account....
. The Opiliones have remained almost unchanged morphologically over a long period. Indeed, one species discovered in China, fossilized by fine grained volcanic ash around 165 million years ago, is hardly discernible from its modern day descendant and belongs to an existing family of harvestman.
Etymology
The Swedish naturalist and arachnologist Carl Jakob SundevallCarl Jakob Sundevall
Carl Jakob Sundevall was a Swedish zoologist.Sundevall studied at Lund University, where he became a Ph.D. in 1823. After traveling to East Asia, he studied medicine, graduating as Doctor of Medicine in 1830....
(1801–1875) honored the naturalist Martin Lister
Martin Lister
Martin Lister FRS was an English naturalist and physician.-Life:Lister was born at Radcliffe, near Buckingham, the son of Sir Martin Lister MP for Brackley in the Long Parliament and his wife Susan Temple daughter of Sir Alexander Temple. Lister was connected to a number of well known individuals...
(1638–1712) by adopting his term Opiliones for this order; Lister taxonomically described three species from England, United Kingdom.
Systematics
- CyphophthalmiCyphophthalmiThe Cyphophthalmi are a suborder of harvestmen, with about 36 genera, and more than hundred described species.The six families are currently grouped into two infraorders, the Tropicophthalmi and the Temperophthalmi; however, these are not supported by modern phylogenetic analysis.They are smaller...
Simon 1879 (c. 100 species)- Tropicophthalmi Shear 1980
- Stylocelloidea Hansen & Sørensen 1904
- StylocellidaeStylocellidaeThe Stylocellidae are a family of harvestmen with about 30 described species, all of which occur from India to New Guinea. Members of this family are from one to seven millimeters long...
Hansen & Sørensen 1904
- Stylocellidae
- Ogoveoidea Shear 1980
- OgoveidaeOgoveidaeThe Ogoveidae are a family of harvestmen with three described species in one genus, Ogovea, which is found in tropical rain forests of equatorial West Africa....
Shear 1980 - NeogoveidaeNeogoveidaeThe Neogoveidae are a family of harvestmen with twelve described species in five genera. However, at least seven species of Huitaca, 17 species of Metagovea and twelve species of Neogovea are currently awaiting description.-Distribution:...
Shear 1980
- Ogoveidae
- Stylocelloidea Hansen & Sørensen 1904
- Temperophthalmi Shear 1980
- Sironoidea Simon 1879
- PettalidaePettalidaeThe Pettalidae are a family of harvestmen with 52 described species and subspecies in eleven genera. Several undescribed species are known or assumed in some genera.-Name:Pettalus is a name from Greek mythology that appears in Ovid's Metamorphoses....
Shear 1980 - SironidaeSironidaeThe Sironidae are a family of harvestmen with more than 30 described species.The family shows a Laurasian distribution, with most species found in temperate Europe and the west coast of North America...
Simon 1879 - TroglosironidaeTroglosironidaeThe Troglosironidae are a family of harvestmen with thirteen described species in a single genus, Troglosiro. Several species, including six undescribed ones, were collected around the island, and more are expected to be found....
Shear 1993
- Pettalidae
- Sironoidea Simon 1879
- Tropicophthalmi Shear 1980
- EupnoiEupnoiThe Eupnoi are a suborder of harvestmen, with more than 200 genera, and about 1,700 described species.They consist of two superfamilies, the Phalangioidea with many long-legged species common to northern temperate regions, and the small group Caddoidea, which have prominent eyes and spiny...
Hansen & Sørensen 1904 (c. 1,800 species)- Caddoidea Banks 1892
- CaddidaeCaddidaeCaddidae is a family of harvestmen with 15 known species, the only family of the Eupnoi superfamily Caddoidea.They have mostly a body length between one and three millimeters.-Distribution:Caddids are widely but discontinuously distributed...
Banks 1892
- Caddidae
- PhalangioideaPhalangioideaPhalangioidea is a superfamily of the harvestman suborder Eupnoi with five recognized families and more than 1,500 species.It is not to be confused with the similar spelled subfamily Phalangodoidea, which is also a harvestman superfamily, but within the infraorder Laniatores.-Families:*...
Latreille 1802- MonoscutidaeMonoscutidaeThe Monoscutidae are a family of harvestmen with 32 known species that all occur in or near Australia and New Zealand.Species range in body length from two to three millimeters and three to ten mm . The chelicerae are enormously enlarged in males of the subfamily Megalopsalidinae. Most species are...
Forster 1948 - NeopilionidaeNeopilionidaeThe Neopilionidae are a family of harvestmen with 15 known species.It has a clearly Gondwanan distribution, with species found in Australia, South Africa and South America, and probably represent relicts of that time....
Lawrence 1931 - SclerosomatidaeSclerosomatidaeThe Sclerosomatidae are a family of harvestmen with about 1,300 known species.-Name:The name of the type genus is combined from Ancient Greek skleros "hard" and soma "body".-Genera:* Gagrellinae Thorell, 1889* Abaetetuba Tourinho-Davis, 2004...
Simon 1879 - PhalangiidaePhalangiidaeThe Phalangiidae are a family of harvestmen with about 380 known species. The best known is Phalangium opilio. Dicranopalpus ramosus is an invasive species in Europe....
Latreille 1802
- Monoscutidae
- Caddoidea Banks 1892
- DyspnoiDyspnoiThe Dyspnoi are a suborder of harvestmen, with about 32 genera, and about 320 described species.Several fossil species are known, including two extinct families.The superfamilies Ischyropsalidoidea and Troguloidea are monophyletic...
Hansen & Sørensen 1904 (c. 320 species)- Ischyropsalidoidea Simon 1879
- CeratolasmatidaeCeratolasmatidaeThe Ceratolasmatidae are a family of harvestmen with eleven described species.The monophyly of this family is questionable; it is composed of three possibly monophyletic groups:...
Shear 1986 - IschyropsalididaeIschyropsalididaeThe Ischyropsalididae are a family of harvestmen with about 40 described species.-Description:Species in this family range in body length from about four to 8.5 mm. They have moderately long legs. The greatly enlarged chelicerae can be almost twice as long as the body. While they share this feature...
Simon 1879 - SabaconidaeSabaconidaeThe Sabaconidae are a family of harvestmen with about 50 known species.The species range in body length from 1.2 to 5.5 mm. The relatively small chelicerae are sexually dimorphic. In Taracus the chelicerae are strongly elongated...
Dresco 1970
- Ceratolasmatidae
- Nemastomatoidea Simon, 1872
- DicranolasmatidaeDicranolasmatidaeThe Dicranolasmatidae are a family of harvestmen with about 20 described species in a single genus.-Description:Species of Dicranolasma range in body length from three to 6.4 mm. Most parts of the body are encrusted with soil particles. The anterior region features a large headlike "hood" with the...
Simon 1879 - NemastomatidaeNemastomatidaeThe Nemastomatidae are a family of harvestmen with about 170 described species in 16 recent genera. Several fossil species and genera are known.Unlike some related currently recognized families, the Nemastomatidae are monophyletic.-Description:...
Simon 1872 - † NemastomoididaeNemastomoididaeNemastomoides is an extinct genus of harvestmen known from the Carboniferous fossil record. The genus is the only member of the family Nemastomoididae and contains three described species...
Petrunkevitch 1955 (fossil: CarboniferousCarboniferousThe Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...
) - NipponopsalididaeNipponopsalididaeThe Nipponopsalididae are a family of harvestmen with two described species.-Description:They range in body length from 2.3 to 4.1 mm. Their eyes are rather large for harvestmen, and they have chelicerae that are longer than their body, and even longer, slender pedipalps and long legs...
Martens 1976
- Dicranolasmatidae
- Troguloidea Sundevall 1833
- † EotrogulidaeEotrogulidaeEotrogulus is an extinct genus of harvestmen known from the Carboniferous fossil record. The genus is the only member of the family Eotrogulidae and contains one species Eotrogulus fayoli. Eotrogulus was found in the Coal Measures of Commentry in northern France, together with Nemastomoides elaveris...
(fossil: Carboniferous) - TrogulidaeTrogulidaeThe Trogulidae are a family of harvestmen with about 45 known species.Members of this species have short legs and live in soil. They have dirt attached to their bodies, to escape predators. Their body length ranges from 2 to 22 mm. The body is in most genera somewhat flattened and leathery...
Sundevall 1833
- † Eotrogulidae
- Ischyropsalidoidea Simon 1879
- LaniatoresLaniatoresLaniatores is the largest suborder of the arachnid order Opiliones with over 4,000 described species worldwide. The majority of the species are highly dependent on humid environments and usually correlated with tropical and temperate forest habitats....
Thorell, 1876 (c. 4,000 species)- Insidiatores Loman, 1900
- Travunioidea Absolon & Kratochvil 1932
- CladonychiidaeCladonychiidaeThe Cladonychiidae are a small family of harvestman with less than twenty described species, within the suborder Laniatores.-Description:Members of this family range from less than two to about four millimeters in body length, with robust, spined pedipalps and rather short legs, although the second...
Hadzi, 1935 - PentanychidaePentanychidaeThe Pentanychidae are a small family of harvestman with about six described species, within the suborder Laniatores.-Description:Pentanychidae range in length from about two to three millimeters...
Briggs 1971 - TravuniidaeTravuniidaeThe Travuniidae are a small family of harvestman with little more than ten described species, within the suborder Laniatores.-Description:Travuniidae are at the most three millimeters long, with slender, unarmed legs and robust, strongly spined pedipalps....
Absolon & Kratochvil 1932
- Cladonychiidae
- Triaenonychoidea Sørensen, 1886
- TriaenonychidaeTriaenonychidaeThe Triaenonychidae are a family of harvestmen with about 120 genera and more than 440 described species.-Description:Most Triaenonychidae are from three to five millimeters long, although some species from South Africa can be only long. Some species in the subfamily Adaeinae are almost long....
Sørensen, 1886 - SynthetonychiidaeSynthetonychiidaeThe Synthetonychiidae are a small family of harvestman with a handful of species in a single genus. They are endemic to New Zealand.-Description:Species in this family are between one and two millimeters long, with legs up to almost six mm.-Relationships:...
Forster 1954
- Triaenonychidae
- Travunioidea Absolon & Kratochvil 1932
- GrassatoresGrassatoresGrassatores is the most diverse infraorder of the Laniatores. It includes over 3,500 species distributed mainly in the World Tropics...
Kury, 2002- SamooideaSamooideaSamooidea is a large superfamily in the Grassatores group of harvestmen. It includes around 380 species distributed throughout the tropics. They are characterized by the complex male genitalia, with eversible complementary sclerites....
Sørensen, 1886- BiantidaeBiantidaeBiantidae is a family of the harvestman infraorder Grassatores with about 130 described species.-Description:Biantidae are between 1.5 and 5.5 millimeters long, with legs ranging from three to 25 mm and enlarged, armed pedipalps...
Thorell, 1889 - EscadabiidaeEscadabiidaeEscadabiidae is a small neotropical family of the harvestman infraorder Grassatores with six described species.-Distribution:All known members of this group are endemic to Brazil...
Kury & Pérez, 2003 - KimulidaeKimulidaeKimulidae is a small neotropical family of the harvestman infraorder Grassatores with about thirty described species.-Distribution:Whereas most species occur in Venezuela, Colombia and the West Indies, the isolated species Tegipiolus pachypus is found in northeastern Brazil. This species also...
Pérez González, Kury & Alonso-Zarazaga, 2007 (= Minuidae Sørensen, 1932) - PodoctidaePodoctidaePodoctidae is a family of the harvestman infraorder Grassatores with about 130 described species.-Description:Body length ranges from 2.5 to 5 millimeters, with leg length ranging from three to almost thirty mm. While most species are brown to yellow, some are deep green. The legs may be ringed in...
Roewer, 1912 - SamoidaeSamoidaeSamoidae is a family of the harvestman infraorder Grassatores with about fifty described species.-Description:The body length of members of this family ranges from about two to almost six millimeters...
Sørensen, 1886 - StygnommatidaeStygnommatidaeStygnommatidae is a small neotropical family of the harvestman infraorder Grassatores with about thirty described species.-Description:Stygnommatidae range from three to six millimeters in body length. Some species have chelicerae that effectively double their length. The pedipalps are strong,...
Roewer, 1923
- Biantidae
- Epedanoidea Sørensen, 1886
- EpedanidaeEpedanidaeEpedanidae is a family of the harvestman infraorder Grassatores with about 200 described species. They are the sister group of the Gonyleptoidea....
Sørensen, 1886
- Epedanidae
- GonyleptoideaGonyleptoideaGonyleptoidea is the most diverse superfamily of the Grassatores. It includes around 2,500 species distributed in the tropics. They are characterized by the simplified male genitalia, with the glans free subapical in the truncus....
Sundevall, 1833- AgoristenidaeAgoristenidaeAgoristenidaeare a neotropical harvestman family of the Suborder Laniatores, in the superfamily Gonyleptoidea.-Name:The name of the type genus is a combination of Ancient Greek agora "gathering" and stenos "few", referring to the rarity of the family at the time of its discovery.-Description:These...
Šilhavý, 1973 - AssamiidaeAssamiidaeAssamiidae, with more than 400 described species, is the third most diverse family of the Suborder Laniatores.-Name:The family name is derived from the Indian province Assam, where the type species of the type genus was collected....
Sørensen, 1884 - CosmetidaeCosmetidaeCosmetidae, with around 700 species, is the second most diverse family of the Suborder Laniatores. They are distributed from Argentina to southern USA, most diverse in northern South America, Central America and Mexico...
Koch, 1839 - CranaidaeCranaidaeThe Cranaidae are a family of neotropical harvestmen within the suborder Laniatores.-Name:The name of the type genus is derived from Cranaus, the successor of Cecrops I as king of Attica in Greek mythology.-Description:...
Roewer, 1913 - GonyleptidaeGonyleptidaeGonyleptidae is a Neotropical family of harvestmen with more than 800 species, the largest in the Suborder Laniatores and the second largest of the Opiiones as a whole...
Sundevall, 1833 - ManaosbiidaeManaosbiidaeThe Manaosbiidae are a family of neotropical harvestmen within the suborder Laniatores.-Name:The name of the type genus is combined from Manaus and Ancient Greek bios "living".-Description:...
Roewer, 1943 - StygnidaeStygnidaeThe Stygnidae are a family of neotropical harvestmen within the suborder Laniatores.-Description:Body length ranges from about one to six millimeters. The color ranges from light brown to reddish...
Simon, 1879 - StygnopsidaeStygnopsidaeThe Stygnopsidae are a small family of harvestmen, with almost all species found in Mexico.-Name:The name of the type genus Stygnopsis is combined from the genus Stygnus and Ancient Greek opsis, "looks like".-Description:...
Sørensen, 1932
- Agoristenidae
- PhalangodoideaPhalangodoideaPhalangodoidea is a superfamily of the harvestman infraorder Grassatores with three recognized families and 220 species. It is not to be confused with the similar spelled subfamily Phalangioidea, which is also a harvestman superfamily, but within the infraorder Eupnoi.-Families:* Oncopodidae...
Simon, 1879- OncopodidaeOncopodidaeThe Oncopodidae are a family of harvestmen within the suborder Laniatores.-Name:The name of the type genus is a combination of Ancient Greek onkos "swelling" and podos "leg".-Description:...
Thorell, 1876 — possibly misplaced - PhalangodidaePhalangodidaeThe Phalangodidae are a family of harvestmen with about 20 genera and more than 100 described species, distributed in the Holarctic Region.It is not to be confused with the harvestman family Phalangiidae, which is in the suborder Eupnoi.-Name:...
Simon, 1879
- Oncopodidae
- Zalmoxoidea Sørensen, 1886
- FissiphalliidaeFissiphalliidaeThe Fissiphalliidae are a small neotropical family of harvestmen within the suborder Laniatores.-Name:The name of the type genus is combined from Latin fissus "split" and Ancient Greek phallos "penis".-Description:...
Martens, 1988 - GuasiniidaeGuasiniidaeThe Guasiniidae are a family of harvestman with three described species from South America.It is, together with the Fissiphalliidae and the Ogoveidae, one of the least diverse harvestman families....
Gonzalez-Sponga, 1997 - IcaleptidaeIcaleptidaeThe Icaleptidae are a small family of neotropical harvestmen within the suborder Laniatores. Although only two species have been described, many more are probably to be discovered.-Name:...
Kury & Pérez, 2002 - ZalmoxidaeZalmoxidaeThe Zalmoxidae are a family of harvestmen within the suborder Laniatores.-Description:Zalmoxidae are small Laniatores of dark brown to dark yellow color with varied darker mottling. Some small edaphic species are pale yellowish.-Distribution:...
Sørensen, 1886
- Fissiphalliidae
- Samooidea
- Insidiatores Loman, 1900
The family Stygophalangiidae (1 species, Stygophalangium karamani
Stygophalangium karamani
Stygophalangium karamani is a species of arachnid. Although sometimes classified as a harvestman in the infraorder Eupnoi , its identity is uncertain, but it is probably a species of Acari .-Name:...
) from underground waters in Macedonia
Republic of Macedonia
Macedonia , officially the Republic of Macedonia , is a country located in the central Balkan peninsula in Southeast Europe. It is one of the successor states of the former Yugoslavia, from which it declared independence in 1991...
is sometimes misplaced in the Phalangioidea. It is not a harvestman.
Fossil record
Despite their long history, few harvestman fossils are known. This is mainly due to their delicate body structure and terrestrial habitat, making it unlikely to be found in sediments. As a consequence, most known fossils have been preserved as amberAmber
Amber is fossilized tree resin , which has been appreciated for its color and natural beauty since Neolithic times. Amber is used as an ingredient in perfumes, as a healing agent in folk medicine, and as jewelry. There are five classes of amber, defined on the basis of their chemical constituents...
.
The oldest known harvestman, from the 400 million years old Devonian
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
Rhynie chert
Rhynie chert
The Rhynie chert is an Early Devonian sedimentary deposit exhibiting extraordinary fossil detail or completeness . It is exposed near the village of Rhynie, Aberdeenshire, Scotland; a second unit, the Windyfield chert, is located some 700 m away...
, already has almost all the characteristics of modern species, placing the origin of harvestmen in the Silurian
Silurian
The Silurian is a geologic period and system that extends from the end of the Ordovician Period, about 443.7 ± 1.5 Mya , to the beginning of the Devonian Period, about 416.0 ± 2.8 Mya . As with other geologic periods, the rock beds that define the period's start and end are well identified, but the...
, or even earlier.
Interestingly, no fossils of Cyphophthalmi
Cyphophthalmi
The Cyphophthalmi are a suborder of harvestmen, with about 36 genera, and more than hundred described species.The six families are currently grouped into two infraorders, the Tropicophthalmi and the Temperophthalmi; however, these are not supported by modern phylogenetic analysis.They are smaller...
or Laniatores
Laniatores
Laniatores is the largest suborder of the arachnid order Opiliones with over 4,000 described species worldwide. The majority of the species are highly dependent on humid environments and usually correlated with tropical and temperate forest habitats....
much older than 50 million years are known, despite the former presenting a basal clade, and the latter having probably diverged from the Dyspnoi more than 300 million years ago.
Naturally, most finds are from comparatively recent times, but it is interesting that while there are more than 20 known species from the Cenozoic
Cenozoic
The Cenozoic era is the current and most recent of the three Phanerozoic geological eras and covers the period from 65.5 mya to the present. The era began in the wake of the Cretaceous–Tertiary extinction event at the end of the Cretaceous that saw the demise of the last non-avian dinosaurs and...
, and at least seven from the Paleozoic
Paleozoic
The Paleozoic era is the earliest of three geologic eras of the Phanerozoic eon, spanning from roughly...
, only one species from the Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
has yet been found.
Paleozoic
The 400 million years old Eophalangium sheari is known from two specimens, one a female, the other a male. The female bears an ovipositorOvipositor
The ovipositor is an organ used by some animals for oviposition, i.e., the laying of eggs. It consists of a maximum of three pairs of appendages formed to transmit the egg, to prepare a place for it, and to place it properly...
and is about 10 millimetre (0.393700787401575 in) long, the male penis can be discerned too. It is not definitely known if both sexes belong to the same species. They have long legs, tracheae
Invertebrate trachea
The invertebrate trachea refers to the open respiratory system composed of spiracles, tracheae, and tracheoles that terrestrial arthropods have to transport metabolic gases to and from tissues....
, and no median eyes.
Brigantibunum listoni from East Kirkton near Edinburgh
Edinburgh
Edinburgh is the capital city of Scotland, the second largest city in Scotland, and the eighth most populous in the United Kingdom. The City of Edinburgh Council governs one of Scotland's 32 local government council areas. The council area includes urban Edinburgh and a rural area...
in Scotland is almost 340 million years old. Its placement is rather uncertain, apart from it being a harvestman.
From about 300 million years ago (mya) there are several finds from the Coal Measures
Coal Measures
The Coal Measures is a lithostratigraphical term for the coal-bearing part of the Upper Carboniferous System. It represents the remains of fluvio-deltaic sediment, and consists mainly of clastic rocks interstratified with the beds of coal...
of North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
and Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
. While the two described Nemastomoides species are currently grouped as Dyspnoi, they look more like Eupnoi.
Kustarachne tenuipes was shown in 2004 to be a harvestman, after residing for almost hundred years in its own arachnid order, the "Kustarachnida".
There are some fossils from the Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...
that are possibly harvestmen, but these are not well preserved.
Described species
- Eophalangium sheari (Eupnoi) — Early Devonian (RhynieRhynieRhynie is a village in Aberdeenshire, Scotland which the A97 road runs through, situated 14 miles northwest of Alford.The Rhynie Chert is named after the village as well as the extinct plant genus Rhynia....
, ScotlandScotlandScotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
) - Brigantibunum listoni (Eupnoi?)— Early Carboniferous (East Kirkton, Scotland)
- Eotrogulus fayoli Thevenin, 1901 (Dyspnoi: † EotrogulidaeEotrogulidaeEotrogulus is an extinct genus of harvestmen known from the Carboniferous fossil record. The genus is the only member of the family Eotrogulidae and contains one species Eotrogulus fayoli. Eotrogulus was found in the Coal Measures of Commentry in northern France, together with Nemastomoides elaveris...
) — Upper Carboniferous (CommentryCommentryCommentry is a commune in the department of Allier in central France. It lies southwest of Moulins by the Orléans railway.-Population:-Economy:...
, FranceFranceThe French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
) - Nemastomoides elaveris Thevenin, 1901 (Dyspnoi: † NemastomoididaeNemastomoididaeNemastomoides is an extinct genus of harvestmen known from the Carboniferous fossil record. The genus is the only member of the family Nemastomoididae and contains three described species...
) — Upper Carboniferous (Commentary, France) - Nemastomoides longipes Petrunkevitch — Upper Carboniferous (Mazon Creek, USA)
- Kustarachne tenuipes Scudder, 1890 (Eupnoi?) — Upper Carboniferous (Mazon Creek, USA)
- Echinopustulus samuelnelsoni Dunlop, 2004 (Dyspnoi?) — Upper Carboniferous (Western MissouriMissouriMissouri is a US state located in the Midwestern United States, bordered by Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas and Nebraska. With a 2010 population of 5,988,927, Missouri is the 18th most populous state in the nation and the fifth most populous in the Midwest. It...
, USA)
Mesozoic
No fossil harvestmen are known from the TriassicTriassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
. They are also so far absent from the Lower Cretaceous Crato Formation
Crato Formation
The Crato Formation is a geologic formation of Early Cretaceous age in northeastern Brazil's Araripe Basin. It is an important Lagerstätte for palaeontologists. The strata were laid down mostly during the early Albian age, about 108 million years ago, in a shallow inland sea...
of Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
, which has yielded many other terrestrial arachnids. An unnamed long-legged harvestman was reported from the Early Cretaceous of Koonwarra, Victoria
Victoria (Australia)
Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....
, Australia, which may be a Eupnoi.
Halitherses grimaldii from Burmese amber (c. ) is a long-legged Dyspnoi with large eyes, which may be related to the Ortholasmatinae (Nemastomatidae).
Cenozoic
Unless otherwise noted, all species are from the EoceneEocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
.
- Trogulus longipes Haupt, 1956 (Dyspnoi: TrogulidaeTrogulidaeThe Trogulidae are a family of harvestmen with about 45 known species.Members of this species have short legs and live in soil. They have dirt attached to their bodies, to escape predators. Their body length ranges from 2 to 22 mm. The body is in most genera somewhat flattened and leathery...
) — GeiseltalGeiseltalThe Geisel valley is a valley in Saxony-Anhalt, Germany, situated west of Merseburg, Saalekreis district. It is named after the River Geisel which rises in Mücheln and is a tributary of the Saale, just under 25 km long....
, GermanyGermanyGermany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate... - Philacarus hispaniolensis (Laniatores: SamoidaeSamoidaeSamoidae is a family of the harvestman infraorder Grassatores with about fifty described species.-Description:The body length of members of this family ranges from about two to almost six millimeters...
?) — Dominican amberDominican amberDominican amber is amber from the Dominican Republic. Resin from the extinct species Hymenaea protera is the source of Dominican amber and probably of most amber found in the tropics.... - Kimula species (Laniatores: KimulidaeKimulidaeKimulidae is a small neotropical family of the harvestman infraorder Grassatores with about thirty described species.-Distribution:Whereas most species occur in Venezuela, Colombia and the West Indies, the isolated species Tegipiolus pachypus is found in northeastern Brazil. This species also...
) — Dominican amber - Hummelinckiolus silhavyi Cokendolpher & Poinar, 1998 (Laniatores: Samoidae) — Dominican amber
- CaddoCaddoThe Caddo Nation is a confederacy of several Southeastern Native American tribes, who traditionally inhabited much of what is now East Texas, northern Louisiana and portions of southern Arkansas and Oklahoma. Today the Caddo Nation of Oklahoma is a cohesive tribe with its capital at Binger, Oklahoma...
dentipalpis (Eupnoi: CaddidaeCaddidaeCaddidae is a family of harvestmen with 15 known species, the only family of the Eupnoi superfamily Caddoidea.They have mostly a body length between one and three millimeters.-Distribution:Caddids are widely but discontinuously distributed...
) — Baltic amberBaltic amberThe Baltic region is home to the largest known deposit of amber, called Baltic amber or succinite, with about 80% of the world's known amber found there. It dates from 44 million years ago... - DicranopalpusDicranopalpusDicranopalpus is a genus of harvestmen with twelve known recent species. Three fossil species have been described, all from Baltic amber, but only D. ramiger is currently considered valid.-Name:...
ramiger (Koch & Berendt, 1854) (Eupnoi: PhalangiidaePhalangiidaeThe Phalangiidae are a family of harvestmen with about 380 known species. The best known is Phalangium opilio. Dicranopalpus ramosus is an invasive species in Europe....
) — Baltic amber - OpilioOpilioOpilio is a genus of harvestmen with more than sixty known recent species.-Name:The genus name is derived from Latin opilio "sheep-master" , used by Plautus, also used by Virgil with the meaning "shepherd".-Species:...
ovalis (Eupnoi: Phalangiidae?) — Baltic amber - Cheiromachus coriaceus Menge, 1854 (Eupnoi: Phalangiidae?) — Baltic amber
- LeiobunumLeiobunumLeiobunum is a genus of the harvestman family Sclerosomatidae with more than a hundred described species.-Description:The teguments are soft or subcoriaceous. The striae of the cephalothorax and of the three last abdominal segments are very distinct; those of the anterior segments are scarcely or...
longipes (Eupnoi: SclerosomatidaeSclerosomatidaeThe Sclerosomatidae are a family of harvestmen with about 1,300 known species.-Name:The name of the type genus is combined from Ancient Greek skleros "hard" and soma "body".-Genera:* Gagrellinae Thorell, 1889* Abaetetuba Tourinho-Davis, 2004...
) — Baltic amber - Histricostoma tuberculatum (Dyspnoi: NemastomatidaeNemastomatidaeThe Nemastomatidae are a family of harvestmen with about 170 described species in 16 recent genera. Several fossil species and genera are known.Unlike some related currently recognized families, the Nemastomatidae are monophyletic.-Description:...
) — Baltic amber - Mitostoma denticulatum (Dyspnoi: Nemastomatidae) — Baltic amber
- Nemastoma incertum (Dyspnoi: Nemastomatidae) — Baltic amber
- SabaconSabaconSabacon is a genus of the harvestman family Sabaconidae with about forty species.Species of this genus have usually thickened pedipalps with stiff, fine hairs, which is unique among harvestmen. Although the small eye tubercle is usually not ornamented, there is a spine on one Nepalese species...
claviger (Dyspnoi: SabaconidaeSabaconidaeThe Sabaconidae are a family of harvestmen with about 50 known species.The species range in body length from 1.2 to 5.5 mm. The relatively small chelicerae are sexually dimorphic. In Taracus the chelicerae are strongly elongated...
) — Baltic amber - Petrunkevitchiana oculata (Petrunkevitch, 1922) (Eupnoi: PhalangioideaPhalangioideaPhalangioidea is a superfamily of the harvestman suborder Eupnoi with five recognized families and more than 1,500 species.It is not to be confused with the similar spelled subfamily Phalangodoidea, which is also a harvestman superfamily, but within the infraorder Laniatores.-Families:*...
) — Florissant, USA (OligoceneOligoceneThe Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
) - Proholoscotolemon nemastomoides (Laniatores: CladonychiidaeCladonychiidaeThe Cladonychiidae are a small family of harvestman with less than twenty described species, within the suborder Laniatores.-Description:Members of this family range from less than two to about four millimeters in body length, with robust, spined pedipalps and rather short legs, although the second...
) — Baltic amber - Siro platypedibus (Cyphophthalmi: SironidaeSironidaeThe Sironidae are a family of harvestmen with more than 30 described species.The family shows a Laurasian distribution, with most species found in temperate Europe and the west coast of North America...
) — Bitterfeld amber - Amauropilio atavus (Cockerell, 1907) (Eupnoi: Sclerosomatidae) — Florissant, USA (Oligocene)
- Amauropilio lacoei (A. lawei?) (Petrunkevitch, 1922) — Florissant, USA (Oligocene)
- Pellobunus proavus Cokendolpher, 1987 (Laniatores: Samoidae) — Dominican amber
- PhalangiumPhalangiumPhalangium is a genus of harvestmen, that occurs mostly in the Old World. The best known species is Phalangium opilio, which is so common in many temperate regions that it is simply called "harvestman".-Species:...
species (Eupnoi: Phalangiidae) — near RomeRomeRome is the capital of Italy and the country's largest and most populated city and comune, with over 2.7 million residents in . The city is located in the central-western portion of the Italian Peninsula, on the Tiber River within the Lazio region of Italy.Rome's history spans two and a half...
, ItalyItalyItaly , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
(QuaternaryQuaternaryThe Quaternary Period is the most recent of the three periods of the Cenozoic Era in the geologic time scale of the ICS. It follows the Neogene Period, spanning 2.588 ± 0.005 million years ago to the present...
)
External links
- Joel Hallan's Biology Catalog (2005)
- Harvestman: Order Opiliones Diagnostic photographs and information on North American harvestmen
- Harvestman: Order Opiliones Diagnostic photographs and information on European harvestmen
- University of Aberdeen: The Rhynie Chert Harvestmen (fossils)
- National Museum page Classification of Opiliones A synoptic taxonomic arrangement of the order Opiliones, down to family-group level, including some photos of the families