Opiliones are an order of arachnids commonly known as harvestmen. About 6,500 species of harvestmen have been discovered worldwide, although the total number of extant species are thought to exceed 10,000. Many species of harvestmen tolerate members of their own species and are often found in groups.

Opiliones usually have exceptionally long legs relative to their body size, exceeding 340mm, with the second pair of legs being longer and functioning as antennae. This is not obvious is short legged species. Most Opiliones have a single pair of eyes in the middle of the head, oriented sideways, which are close to useless and cannot form images, and thus rely heavily on their longer second pair of legs to explore their environment.

As in all Arachnida, the body in the Opiliones consists of two “segments”, the anterior cephalothorax/ prosoma, and the posterior abdomen/ opisthosoma.  But unlike spiders Opiliones body appears to be a single oval structure because the connection between the cephalothorax and abdomen is broad. Other differences include the fact that Opiliones have no venom glands and as such pose no danger to humans.

The abdominal segments can also be modified into different structures and thus give a different morphological look. In the males of some species the first five abdominal segments are fused into a dorsal shield and then fused with the carapace. In other species, the two posterior abdominal segments are reduced.

Harvestmen have a pair of defensive scent glands that secrete a peculiar-smelling fluid containing quinones when disturbed. Opiliones breathe through tracheae, with a pair of spiracles located between the base of the fourth pair of legs and the abdomen. In more active species, spiracles are found on the legs.

Unlike most arachnids which are typically pure predators and carnivorous, Opiliones have an unusually broad, many species being omnivorous, eating primarily small insects and all kinds of plant material and fungi. Some are scavengers, feeding upon dead organisms, bird dung, and other fecal material. Also, unlike other arachnids, Opiliones can swallow solid food, not needing to liquefy their food before ingesting, hence do not have a “filtering” mechanism, making them susceptible to internal parasites which can be ingested. Unlike spiders, harvestmen have no silk glands and thus do not build webs, but rather ambush their prey, while some actively hunt.

Most harvestmen reproduce sexually, although parthenogenetic species do occur. Unlike other arachnids male Opiliones have a penis and as such can directly copulate, instead of deposition of a spermatophore. Males of some species sometimes offer a nuptial gift secretion to the female before copulation. In many species, males defend territories and perform mate guarding after copulation. Some species, males also exhibit post-copulatory behavior where the male seeks out and shakes the female’s sensory leg, enticing the female into mating a second time.

Females lay eggs from an ovipositor several months after mating. Some species build nest, while the males in some species exhibit parental care, guarding eggs laid in the same nest by few females, usually from the females themselves.

Most species are nocturnal and drab in color, in contrast to diurnal species which are more often more colorful with vivid patterns and reticulations.

Source: Wikipedia

Family Assamiidae

Assamiidae 086A3647
(Singapore)
Assamiidae 0F1A5196
(Sarawak, Malaysia)

Family Beloniscidae

Subfamily Beloniscinae

Beloniscus albiephippiatus
(Singapore)

Family Biantidae

Subfamily Biantinae

Biantes sp. 086A3645
(Singapore)

Family Cosmetidae

Cosmetidae 0F1A5113
(Sumaco, Ecuador)
Cosmetidae 0F1A8819
(Tandayapa, Ecuador)
Cosmetidae 0F1A9149
(Tandayapa, Ecuador)
Cosmetidae 0F1A5617
(Sumaco, Ecuador)
Cosmetidae 0F1A8715
(Tandayapa, Ecuador)
Cosmetidae 0F1A8745
(Tandayapa, Ecuador)

Family Cranaidae

Clinocippus albater
(Tandayapa, Ecuador)
Phareicranaus sp. 0F1A8828
(Tandayapa, Ecuador)
Phareicranaus sp. 0F1A9426
(Tandayapa, Ecuador)
Cranaidae 0F1A1822
(Milpe, Ecuador)
Cranaidae 0F1A0296
(Mindo, Ecuador)
Cranaidae 0F1A0328
(Mindo, Ecuador)
Cranaidae 0F1A5085
(Sumaco, Ecuador)
Cranaidae 0F1A5574
(Sumaco, Ecuador)
Cranaidae 0F1A5664
(Sumaco, Ecuador)
Cranaidae 0F1A5676
(Sumaco, Ecuador)
Cranaidae 0F1A8722
(Tandayapa, Ecuador)
Cranaidae 0F1A8784
(Tandayapa, Ecuador)
Cranaidae 0F1A8810
(Tandayapa, Ecuador)
Cranaidae 0F1A9148
(Tandayapa, Ecuador)
Cranaidae 0F1A5521
(Sumaco, Ecuador)
Cranaidae 0F1A8755
(Tandayapa, Ecuador)
Cranaidae 0F1A8757
(Tandayapa, Ecuador)
Cranaidae 0F1A4790
(Sumaco, Ecuador)

Family Epedanidae

Ependanidae 0F1A0470
(Singapore)
Epedanidae 0F1A8775
(Sabah, Malaysia)
Epedanidae 0F1A3568
(Sarawak, Malaysia)
Epedanidae 0F1A7472
(Sarawak, Malaysia)
Epedanidae 0F1A3169
(Doi Inthanon, Chiangmai)

Subfamily Acrobuninae

Metacrobunus sp. 0K0A0377
(Singapore)

Family Podoctidae

Hoplodino continentalis
(Singapore)
Podoctidae 0F1A3332
(Sabah, Malaysia)
Podoctidae 0F1A7793
(Sarawak, Malaysia)

Family Sandokanidae

Sandokan sp. 086A1143
(Singapore)
Sandokanidae 0F1A5019
(Sarawak, Malaysia)
Sandokanidae 086A8404
(Singapore)

Family Sclerosomatidae

Dentobunus sp. 0K0A1431
(Singapore)
Sclerosomatidae 0F1A3084
(Sarawak, Malaysia)
Sclerosomatidae 0F1A3309
(Kinabalu, Malaysia)
Sclerosomatidae 0F1A0149
(Sabah, Malaysia)
Sclerosomatidae 0F1A5337
(Sumaco, Ecuador)
Sclerosomatidae 086A7560
(Singapore)
Sclerosomatidae 0F1A0791
(Singapore)
Sclerosomatidae 0F1A5234
(Sarawak, Malaysia)
Sclerosomatidae 0F1A7750
(Sarawak, Malaysia)
Sclerosomatidae 0F1A0796
(Singapore)
Sclerosomatidae 0F1A1633
(Sabah, Malaysia)
Sclerosomatidae 0F1A7617
(Sabah, Malaysia)
Sclerosomatidae 0F1A0787
(Singapore)
Sclerosomatidae 0F1A0647
(Mindo, Ecuador)
Sclerosomatidae 0F1A3315
(Kinabalu, Malaysia)
Sclerosomatidae 0F1A2085
(Kaeng Krachan NP, Thailand)
Sclerosomatidae 0F1A2139
(Kaeng Krachan NP, Thailand)
Sclerosomatidae 0F1A2479
(Kaeng Krachan NP, Thailand)
Sclerosomatidae 2157
(Doi Inthanon NP, Thailand)
Sclerosomatidae 0F1A5030
(Sabah, Malaysia)
Sclerosomatidae 0F1A4664
(Doi Inthanon, Thailand)
Sclerosomatidae 0F1A0011
(Johore, Malaysia)
Sclerosomatidae 0F1A3196
(Doi Inthanon, Thailand)
Sclerosomatidae 0F1A3524
(Doi Inthanon, Thailand)
Sclerosomatidae 0F1A3800
(Doi Inthanon, Thailand)
Sclerosomatidae 0F1A3979
(Doi Inthanon, Thailand)
Sclerosomatidae 0F1A3989
(Doi Inthanon, Thailand)
Sclerosomatidae 0F1A4648
(Doi Inthanon, Thailand)
Sclerosomatidae 0F1A5741
(Sabah, Malaysia)

Family Stylocellidae

Miopsalis sp. 0F1A4285
(Sarawak, Malaysia)

Family Tithaeidae

Tithaeus sp. 086A3653
(Singapore)

Family Triaenonychidae

Subfamily Triaenonychinae

Acumontia sp. 0F1A0163
(Andasibe, Madagascar)