Harvestman
( Opiliones )


2011-0517-EB070000-ARA00871-Opiliones[1735h17s,L,A,wood-log]{MDame}-G.jpg

PHOTO COMMENT

IDENTIFICATION
Identification:Opiliones
)
Common Name:Harvestman
Life Stage:(A) adult

PHYLOGENY

Phylum:Arthropoda
Class:Arachnida
Order:Opiliones
Taxon Code:ARA00871
ITIS/TSN:82753

LOCATION DETAILS
Location Name
Briones Regional Park, Briones Regional Park, Briones Regional Park, EBRPD, 2537 Reliez Valley Rd., Martinez
County:Contra Costa County
ECI Site#:CAEB070000
Open Space Location:Briones Regional Park, EBRPD

RECOGNITION
Recognition
BugGuide.net: "Easily separated from spiders by the broad fusion of the two body segments, so that the body appears to be composed of a singular segment. Also, as they do not possess silk glands, harvestmen can't form webs. Uniquely among the arachnids fertilization is direct: males possess a penis (also referred to in the literature as pene, aedagus or intromittent organ)."
Description
Easily separated from spiders by the broad fusion of the two body segments, so that the body appears to be composed of a singular segment. Also, as they do not possess silk glands, harvestmen can't form webs. Uniquely among the arachnids fertilization is direct: males possess a penis (also referred to in the literature as pene, aedagus or intromittent organ).
Body Length
Variable; body sizes range from a few millimeters to a few centimeters. Legs are several times the size of the body in the more familiar daddy-long-legs forms of the Phalangioidea.
Diversity
More than, 6,500 species worldwide arranged into 46 families of 4 suborders (of which Laniatores is by far the largest, with more than 4,100 species.
Similar Taxa
Although often mistaken for spiders, these arachnids are more closely related to scorpions

BIOLOGY
In some cases, in dry climates, they gather in large numbers during the day, probably to avoid dessication, and wander about in search of food after the sun goes down.
Habitat
All habitats (except possibly deserts) in Canada & the US: forests, grasslands, wetlands, mountains, caves, chaparral, and anthropogenic habitats.
Range
Global, except Antarctica
Diversity
More than, 6,500 species worldwide arranged into 46 families of 4 suborders (of which Laniatores is by far the largest, with more than 4,100 species.
Active Period
Season: Not likely to be found in winter months in northern/montane regions, except as overwintering populations in refugia (e.g., caves).
Development
Egg, juvenile, adult. Some reproduce sexually (direct fertilization, males possess a penis); others, parthenogenetically (i.e., without males).

CREDITS
Photographer
Mike Dame
Insect Sciences Museum of California

References
Order Opiliones - Harvestmen. (http://bugguide.net/node/view/2405). Accessed March 12, 2016. .
ITIS.


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