Yellowline Arrow Crab

Pronunciation

How to pronounce Stenorhynchus seticornis: /stɛnoʊˈrɪŋkəs ˌsɛtɪˈkɔrnɪs/

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Summary

Stenorhynchus seticornis, known as the yellowline arrow crab, is a marine crab often found in association with sea anemones. It displays nocturnal and territorial behavior, decorating its body for camouflage or predator deterrence. Its reproductive cycle is influenced by environmental factors, and it plays a significant role in reef ecosystems as a predator of smaller marine invertebrates.

Physical Characteristics

Triangular body with a long pointed rostrum having serrate edges; carapace may reach up to 6 cm (2.4 in) long; legs thin and long, up to 10 cm (3.9 in) across; variable coloration, often golden, yellow, or cream with brown, black, or iridescent-blue lines; reddish or yellow legs; blue or violet claws.

Identification Tips

Diagnostic features include triangular body, long pointed snout (rostrum), fine dark lines on carapace, and violet tips on claws.

Habitat

Found in shallow sub-tidal areas on rock bottoms, corals, calcareous algae, and soft sediments such as shelly gravel and sand; commonly associated with sea anemones.

Distribution

Restricted to the Occidental Atlantic, from North Carolina and Bermuda to Argentina, including the Caribbean Sea; inhabits coral reefs at depths of 10–30 feet (3.0–9.1 m).

Diet

Eats small feather duster worms and other coral reef invertebrates.

Life Cycle

During mating, the male places a spermatophore on the female, which she uses to fertilize her eggs. Fertilized eggs are carried on the female's pleopods until ready to hatch into zoea larvae, which swim to the ocean surface and feed on plankton, growing through a series of moults until metamorphosing into adults.

Reproduction

Breeding period is regulated by climate; size of the female affects the number of eggs per batch, with larger females producing more eggs.

Ecosystem Role

Preys on small invertebrates in coral reef environments, also maintains balance by controlling bristle worm populations in reef aquariums.

Similar Taxa

• Decorator crab

Tags

• marine crab
• Shallow sub-tidal
• Caribbean
• Coral reefs
• Nocturnal
• Territorial