Crustaceans, millipedes, and centipedes of Columbia County, Oregon

Crustaceans have jointed legs. Many (including crabs, lobsters, crayfish, and shrimp) are aquatic and have 10 appendages including their claws, though brine shirmp can have 22 legs. Some isopods, such as woodlice, live on land and have 14 legs.

List of all crustaceans recorded in Columbia County

Signal Crayfish oregon columbia county
Signal Crayfish – Our native “crawdad”, can be identified by smooth claws with white bump at joint and a single body plate. (photo © Karen & Mike)
Red Swamp Crayfish – Bumps on claws and a split body plate. Introduced from Louisiana, can wreck native crayfish, fish and amphibian populations. (photo © dickwood)

Western Rockslater Ligidium gracile isopod columbia county northwestern oregon aquatic semiaquatic
Western Rockslater – A streamlined isopod with narrowing multi-segmented “tail” that has two filaments on the end. Semiaquatic, often under streamside debris. (photo © Ian Cruickshank)
Western Waterslater Caecidotea occidentalis isopod columbia county northwestern oregon aquatic semiaquatic
Western Waterslater – Flat isopod with long antennae and large broad segment at end of body. Fully aquatic in its habits. (photo © Abigail Skoda)
common pill woodlouse columbia county oregon
Common Pill Woodlouse – The only woodlouse species that rolls into a ball with no gaps. Feeds on decaying plant matter and lichen. Originally from Europe, introduced to the USA. (photo © Jessica Hird)
Common Woodlouse – Also known as “Common Shiny Woodlouse”, it feeds on dead plants, animals, and wood. Introduced to the USA from Europe. (photo © Jessica Hird)
Rough Woodlouse – Often found in communities with other woodlice species. Feeds on decaying plant matter. An introduced species from Europe. (photo © Jessica Hird)
Common Striped Woodlouse – Known as “Fast Woodlouse” as it runs away when exposed rather than hunkering down like the other species. Introduced from Europe. (photo © Jessica Hird)
Oregon Fairy Shrimp Eubranchipus oregonus oregon columbia county
Oregon Fairy Shrimp – To 1.5″. Use 22 legs to swim upside down. Found only in forested vernal ponds. Threatened by destruction of forest wetland. (photo © Saelon Renkes)
Western Bog Crangonyctid Crangonyx richmondensis occidentalis
Western Bog Crangonyctid – A small freshwater amphipod reaching 0.5″ long. It is found in ponds and other wetlands. (photo © Smithsonian Marine Geo)
Lacustrine Scud Gammarus lacustris oregon northwest columbia county
Lacustrine Scud – This scud reaches 0.8″ long. Scuds are small shrimp-like amphipods that feed on the detritus of waterways. (photo © Corey Lange)
Calanoid Copepods Order Calanoida oregon northwest columbia
Calanoid Copepods – Tiny red crustaceans typically less than 0.1″ long. Often referred to as “plankton” in ocean, can reach large numbers in ponds. (photo © Jon Hakim)

Millipedes and centipedes form a group called Myriapods, which means “many-legged”. Different species have anywhere from several dozen to several hundred legs. Millipedes eat decaying plant matter while centipedes are predators that hunt down insects and other small creatures.

List of all myriapods recorded in Columbia County

yellow-spotted millipede columbia county oregon
Yellow-spotted Millipede – Found in moist forest where it composts leaf litter. Emits hydrogen cyanide as a defense mechanism. (photo © Melissa McMasters)
Black Round Millipede (Tylobolus uncigerus) – A large millipede up to 4″ long, it is native to the moist regions west of the Cascades. (photo © Tomas Quinones)
Greenhouse Millipede – Originally native to Japan, it is now found in suitable habitats across the world, usually in greenhouses and gardens. (photo © giorege1959)
Pacific Flat-backed Millipede (Nearctodesmus insulanus) – A Flat-backed Millipede found only in the coastal ranges of the Pacific Northwest. (photo © William Leonard)
Brown Centipede – Native to Europe but now found worldwide, this short (~1″) brown centipede is found in yards and gardens. It has 30 legs. (photo © Ryzhkov Oleg)
Thorn-tailed Bark Centipede (Scolopocryptops spinicaudus) – These 2-3″ Bark Centipedes are found under the bark of dead trees in moist coastal forest. They have 46 legs. (photo © James Bailey)
Crimson Soil Centipede (Strigamia epileptica) – A very long but very slender local centipede, it can have over 150 legs. They are found under rocks or logs of the forest soil. (photo © W. Mason)
House Centipede columbia county oregon
House Centipede – Originally from Mediterranean but now in and near homes everywhere, this long-legged centipede can cover 15″ a second. (photo © Keir Morse)

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