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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)

-Squat Lobsters and Porcelain Crabs (Superfamily Galatheoidea)

-Porcelain Crabs (Family Porcellanidae)

-Genus Polyonyx


Polyonyx is a genus of small porcelain crabs in the family Porcellanidae. 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.

Polyonyx

Polyonyx (Genus)

Diet

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

  • Use large, feathery mouthparts (third maxillipeds) to capture food particles from passing water currents.

  • Occasionally feed on fine detritus trapped around their host's tube.

Range

  • The genus Polyonyx is distributed throughout tropical and subtropical oceans worldwide.

  • In the eastern Pacific, several species occur from the Gulf of California south along the Pacific coast of Mexico, Central America, and into South America.

  • Species of Polyonyx are found along the Pacific coast of Guerrero, including the Zihuatanejo region, where they inhabit suitable tube-dwelling invertebrate communities.

Habitat

  • Live almost exclusively inside or at the entrance of the tubes of polychaete worms (especially chaetopterid parchment worms) or occasionally in the burrows of other marine invertebrates.

  • Found in sandy bays, mudflats, estuaries, seagrass beds, and shallow subtidal soft-bottom habitats, generally from the intertidal zone to depths of 50 m (165 ft) or more.

  • Many species live as male–female pairs, sharing a single host tube for much of their lives.

Size

  • Carapace width: 0.8–2.5 cm (0.3–1.0 in), depending on the species.

  • Overall body length: 2–5 cm (0.8–2.0 in).

  • Weight: Typically 1–10 g.

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