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Crustaceans of Zihuatanejo

SUBPHYLUM CRUSTACEA

-Animals (Kingdom Animalia)

-Arthropods (Phylum Arthropoda)

-Crustaceans (Subphylum Crustacea)

-Typical Crustaceans (Superclass Multicrustacea)

-Malacostracans (Class Malacostraca)

-Decapods, Isopods, and Allies (Subclass Eumalacostraca)

-Decapods and Krill (Superorder Eucarida)

-Decapods (Order Decapoda)

-Crabs, Lobsters, Shrimps, and Allies (Suborder Pleocyemata)

-True Crabs (Infraorder Brachyura)​

-Eubrachyuran Crabs (Zoosection Eubrachyura)

-Thoracotrematan Crabs (Zoosubsection Thoracotremata)

-Land, Shore, and Marsh Crabs (Superfamily Grapsoidea)

-​Land Crabs (Family Gecarcinidae)


Although they resemble true crabs, porcelain crabs are more closely related to squat lobsters and hermit crabs within the infraorder Anomura. Species in Polyonyx are typically small, flattened, and delicate, often only a few centimeters across. They have broad front claws (chelae) and a smooth to lightly sculptured carapace. Like other porcelain crabs, they possess large, feathery mouthparts (maxillipeds) used for filter feeding, which they extend into the water current to capture plankton and suspended particles.

Porcelain Crabs

Porcellanidae (Family)

Diet

  • Primarily filter feeders, consuming phytoplankton, zooplankton, microscopic algae, bacteria, and suspended organic particles.

  • Many species also graze on detritus, biofilms, and fine organic matter deposited on rocks and coral.

  • Capture food using large, feathery mouthparts (third maxillipeds), which are extended into the current like miniature fans.

Range

  • Found in tropical, subtropical, and temperate oceans worldwide.

  • Along the eastern Pacific, porcelain crabs occur from the Gulf of California south through the Pacific coasts of Mexico, Central America, and South America.

  • Numerous species inhabit the Zihuatanejo region, including members of the genera Petrolisthes, Polyonyx, Pachycheles, Megalobrachium, Neopisosoma, and Megalobrachium.

Habitat

  • Inhabit rocky intertidal shores, tide pools, coral reefs, mangrove roots, oyster beds, sandy bottoms, and seagrass meadows.

  • Most species shelter beneath rocks, within crevices, under coral rubble, or among sponges and oysters.

  • Some species live in close association with tube worms, sea anemones, or corals, while others occupy wave-swept rocky shores from the intertidal zone to depths exceeding 100 m (330 ft).

Size

  • Carapace width: 1–6 cm (0.4–2.4 in), depending on the species.

  • Overall leg span: Up to 12 cm (4.7 in).

  • Weight: Typically 2–60 g.

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