Bay Ghost Shrimp, Neotrypaea californiensis
Ghost Shrimp of the Callianassidae Family are crustaceans in the Phylum Arthropoda and in the Class Malacostraca. They have 5 head segments, 8 thoracic segments, and 6 abdominal segments. The head and thorax are usually combined as a cephalothorax. Their head includes a pair of antennae, a pair of antennules, and the mouth. These animals have a two chambered stomach. Ghost Shrimps, like crabs, crayfish and lobsters, are Decapods meaning that 5 pairs of appendages function as legs (pereiopods), 3 pairs function as mouth parts (maxillipeds), and 1 pair is modified into enlarged pincers (chalae). The Ghost Shrimps in the Family Callianassidae are pale to whitish in color, from which they derive their name, and all have two unequally sized claws. Otherwise, the characteristics that define these Ghost Shrimps are not easily observed in the field. Close observation of these shrimp will show that the first abdominal segment is shorter and narrower than the remaining segments and that the abdominal appendages are not oar-shaped. Ghost Shrimp can reach a maximum length of 15 cm (5.9 inches).
Ghost Shrimp are found worldwide in temperate and tropical seas from the intertidal zone intertidally (or subtidally) to depths as great as 1,050 m (3,444 feet). Ghost Shrimp are burrowers, that usually reside in extensive burrows in sand or mud substrate. Most burrows are branched, with multiple entrances. Some burrows extend 75 cm (30 inches) below the surface of the substrate. Some species may be found in burrows in porous rock or coral, or under rocks. They utilize the hairs on their legs to feed on detritus and plankton, which they filter from the ambient water, or the sediment. They often store dead plant matter in their burrows. In turn Ghost Shrimp are preyed upon by crustaceans, fish, and mollusks. Ghost Shrimp often share their burrows with other animals, including clams, gobies, polychaetes, and pistol shrimp. The burrowing activity of Ghost Shrimp influences the chemical and geophysical properties of the sediment (bioturbation), and plays an important ecological role.
The Callianassidae Family is a taxonomically active Family, with multiple subfamilies, and frequent discussions as to which species and genera belong where. At present there are 234 species in the Callianassidae Family of which 5 are found along Mexico’s Pacific Coast.