Palaemonidae Family of Shrimp

Two Shrimp of the Palaemonidae Family can be found in this website:

Phylogeny: Palaemonid Shrimp of the Palaemonidae Family belong to the phylum Arthropoda and the subphylum Crustacea. They are in the super class Multicrustacea, the class Malacostraca, the subclass Eumalacostraca,  the superorder Eucarida, the order Decapoda, the suborder Pleocyemata, the infraorder Caridea, and the superfamily Palaemonoidea. The Palaemonidae Family is one of two families in this superfamily. The Palaemonidae Family is very large and diverse. It  contains one hundred fifty-four genera and around twelve hundred species. Species in this family are commonly called Commensal Shrimp, based on their interspecific relationships. The name Palaemonidae originates from the mythological Greek sea-god Palaemо̄n.

Morphology: Palaemonid Shrimp have 5 head segments, 8 thoracic segments, and 6 abdominal segments. Their head and thorax are combined as a cephalothorax. The head includes a pair of antennae, a pair of antennules, and the mouth. They have 5 pairs of appendages that function as legs (pereiopods), 3 pairs function as mouth parts (maxillipeds), and 1 pair is modified into enlarged pincers (chalae). They have pincers on their first and second thoracic legs, and some species have a very long second pair of thoracic legs. Palaemonid Shrimp are considered Caridean Shrimp (in the infraorder Caridea). Caridean shrimp have a cylindrical carapace that is somewhat laterally, or dorso-ventrally, compressed. Unlike peneaid or sergestid shrimps, the abdomen is not compressed. Palaemonid Shrimp may be brightly colored, pale, or transparent (Glass Shrimps). The majority of Palaemonid Shrimp are less than 4.0 cm (1.5 inches) in length, but some reach 15 cm (5.9 inches) in length.

Habitat and Distribution: Palaemonid Shrimp are very diverse in their lifestyles. They are found in freshwater, marine, and stygian (cave) environments. They may be on soft or hard substrates or on plants or animals. Of the marine species, most are found in shallow water, but some reach depths of 1,285 m (4,215 feet). The marine species are found worldwide in tropical to temperate seas. At least fifty-three species from this family are found in Mexican waters.

Reproduction: Palaemonid Shrimp are gonochoric (male or female for life). The reproduce sexually through indirect fertilization. The male transfers a sperm packet (spermatophore) to the female’s abdomen. As the female releases her eggs they are fertilized. The female carries the fertilized eggs on her pleopods. In most species the eggs hatch into planktonic larvae. Most species will produce multiple broods per year.

Ecosystem Roles: Most Palaemonid Shrimp live in close relationships with other species. These relationships may be mutualistic, commensal, or semi-parasitic. Host animals include; sponges, corals, sea anemones, sea cucumbers, ascidians, and other decapods. Many species act as “cleaner shrimp”, cleaning fish of parasites and dead skin.   Most are either carnivores or detritivores, and feed by scavenging. They are prey for fish, octopus, and other decapods.