Native Crustacean


 In Puerto Rico the freshwater shrimp and crabs play an important role in aquatic ecosystems as part of the food chain and as recyclers of organic material.


Macrobrachium spp.


Identification and Behavior

  • For Macrobrachium, the legs are modified to captureaprey.
  • Adults range up to 12 inches body length.
  • Color pattern depends on the species and the individual.
  • Five species of this family can be found at El Yunque.
  • Reproductive pattern similar to Atya; the freshwater shrimp of the Caribbean is characterized by amphidromy, where downstream migration of one or more life stages is required.
  • Important as a traditional fishery.


Xiphocaris elongata


Identification and Behavior

  • Endemic to the West Indies.
  • Normally feeds on decomposing vegetation such as leaf litter, and particles of algae. First two pairs of legs are used to “grab” the food and place it in the mouth.
  • Color range from grayish to transparent, with a very thin and smooth exoskeleton.
  • It has a large spine (rostrum) in the front of the head that varies in size, being longer when predatory fish are present in the stream.
  • Reproductive pattern similar to Atya and Macrobrachium.


Epilobocera sinuatifrons


Identification and Behavior

  • The only freshwater crab in the island; endemic.
  • Shells in adults range up to about 5 inches across.
  • Color ranges from dark brown to nearly coffee, often with yellow spots on the joints in the legs and claws.
  • Juveniles, live entirely in freshwater, are spotted brown in color, and can be as large as adults but considerably heavier.
  • Unlike most crabs, which release larvae that undergo metamorphosis, larval stages are completed entirely within the eggs prior to hatching.


Atya spp.

 Identification and Behavior

  • Modified legs with brush-like structures on the tips. The members of this family, Atyidae, are filter feeders.
  • 7 species of this family are found in El Yunque.
  • Adults range up to about 5 inches in body length.
  • Color ranges from black to nearly olive green, often with yellow stripes the joints of the legs.
  • Adults reproduce in the upper parts of the stream, where they release larvae which then move downriver towards the estuaries (river mouths).