Sicyoniidae Family of Rock Shrimp
One Rock Shrimp from the Sicyoniidae Family can be found in this website:
Target Rock Shrimp, Sicyonia penicillata. A representative of the Sicyoniidae Family of Rock Shrimp.
Phylogeny: Rock Shrimp of the Sicyoniidae Family are in the phylum Arthropoda, the subfamily Crustacea, the superclass Multicrustacea, and the Class Malacostraca. They are in the subclass Eumalacostraca, the superorder Eucarida, the order Decapoda, the suborder Dendrobranchiata, and the superfamily Penaeoidea. The Sicyoniidae Family is one of five families within this superfamily. The Sicyoniidae Family contains one genus and fifty-two species. The name Sicyoniidae comes from the name of the ancient Greek city/state, Sicyon or Sikyon, though it is not known what that location has to do with this family.
Morphology: Sicyoniid Shrimp have 5 head segments, 8 thoracic segments, and 6 abdominal segments. The head and thorax are combined as a cephalothorax. The head includes a pair of antennae, a pair of antennules, and mouth parts. Sicyoniid Shrimp have five pairs of appendages that function as legs (pereiopods). These legs are well-developed, and the first 3 pairs have small claws. They have 6 pairs of pairs of appendages along their abdomen. The first 5 pairs function as swimmerets (pleopods). The last pair is flattened to form a tail fan. They differ from other shrimps in that the last three pairs of its pleopods are uniramous ( not divided into branches), rather than biramous (dividing to form 2 branches). Sicyoniid Shrimp are characterized by a rigid exoskeleton, a carapace that extends over the thoracic segments, and dendrobranchiate (branching like a tree) gills. The carapace is thick and stony in appearance, and lacks postorbital spines. The cervical grooves are very faint or absent The rostrum is short and armed with dorsal teeth. The ventral margin lacks teeth. In most species the telson (posterior terminal segment of abdomen) has a spine on both sides of the tip. Most species in this family are drably colored, but some have bright patches of color. The largest species in this family reach around 18 cm (7 inches) in length.
Habitat and Distribution: Sicyoniid Shrimp may be found on sand, mud, rocks, or coral. Some species in this family are found in the intertidal zone, but most tend to be in deeper subtidal water. They reach a maximum depth of around 880 m (2,886 feet), and some sources extend that depth to 1,000 m (3280 feet). Sicyoniid Shrimp are found worldwide in temperate to tropical seas. At least thirteen species from this family are found in Mexican waters.
Reproduction: Sicyoniid Shrimp are gonochoric (male or female for life) and reproduce sexually with indirect sperm transfer. The male transfers a sperm packet (spermatophore) to the female’s abdomen. As the female releases her eggs they pass the spermatophore and are fertilized. The eggs develop into planktonic larvae, often in a day or less, and later settle as benthic juveniles. The have high reproductive rates, in part to offset their short lifespans, typically 20-22 months.
Ecosystem Roles: Sicyoniid Shrimp are primarily opportunistic carnivores, feeding on crustaceans, mollusks, other invertebrates, and fish. In turn they are preyed upon by shore birds, cephalopods, other crustaceans, and fish. They are known to host parasitic helminth cestodes. The commercial harvest of Sicyoniid Shrimp used to be insignificant due to their hard shells and deeper habitat. Because of technological advancements, some species now are an important fishery, especially in the Western Atlantic.