The Opiliones are an order of arachnids colloquially known as harvestmen, harvesters, or daddy longlegs. As of April 2017, over 6,650 species of harvestmen have been discovered worldwide, although the total number of extant species may exceed 10,000. The order Opiliones includes five suborders: Cyphophthalmi, Eupnoi, Dyspnoi, Laniatores, and Tetrophthalmi, which were named in 2014.
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.
The Eupnoi are a suborder of harvestmen, with more than 200 genera, and about 1,700 described species.
The 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.
Megabunus is a genus of harvestmen with six known recent species. All occur in Europe, mostly in the vicinity of the Alps.
The Neopilionidae are a family of harvestmen.
Caddidae is a family of harvestmen arachnids with 15 known species, the only family of the Eupnoi superfamily Caddoidea.
An ozopore is the opening of a defensive gland present in some arthropods, notably in millipedes of the order Polydesmida and in harvestmen, the eight-legged arachnids also known as "daddy long-legs". The glands themselves are known as ozadenes, also called "scent glands", "repugnatorial glands", "odoriferous glands" or "stink glands" by various authors. The name is derived from Ancient Greek ozo "smell" and Latin porus "pore, small opening".
Eotrogulus 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. Eotrogulus was previously thought to be a trigonotarbid.
Nemastomoides 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. Nemastomoides elaveris was found in the Coal Measures of Commentry in northern France, together with Eotrogulus fayoli.
The Ceratolasmatidae are a family of harvestmen with eleven described species.
The Stygnidae are a family of neotropical harvestmen within the suborder Laniatores.
The Cranaidae are a family of neotropical harvestmen within the suborder Laniatores.
The 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.
Kimulidae is a small neotropical family of the harvestman infraorder Grassatores with about thirty described species.
The Fissiphalliidae are a small neotropical family of harvestmen within the suborder Laniatores.
The Synthetonychiidae are a small family of harvestman with a handful of species in a single genus. They are endemic to New Zealand.
The Travuniidae are a small family of harvestman with little more than ten described species, within the suborder Laniatores.
The Cladonychiidae are a small family of harvestman with about 33 described species, within the suborder Laniatores.
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 (labrum), two pairs of coxapophyses and often a labium.
