The Brown Guard Crab, scientifically known as Trapezia digitalis, is a fascinating crustacean found in coral reefs throughout the Indo-Pacific region. This crab exhibits a unique symbiotic relationship with corals, playing a crucial role in the health of these delicate ecosystems.
Description & Characteristics
Trapezia digitalis is characterized by its brown to reddish-brown carapace, which can grow to a maximum size of about 3 centimeters. Its body is flattened and broad, with distinctive, pointed projections on its sides. These projections, along with its short, stout legs, give it a distinct appearance. The crab’s eyes are prominent and located on stalks, providing excellent vision within its coral habitat.
Habitat and Occurrence
Trapezia digitalis is primarily found in coral reefs throughout the Indo-Pacific region. These crabs are most commonly observed in shallow, tropical waters, typically residing within the intertidal zone and the neritic zone. Their distribution extends from the Red Sea and East Africa to the Pacific Ocean, encompassing a wide range of marine ecosystems.
Taxonomy
The species Trapezia digitalis belongs to the Class: Malacostraca, Order: Decapoda, and Family: Trapeziidae. This family, known as the “guard crabs,” consists of a variety of crabs associated with corals. The Trapeziidae family is further categorized within the Infraorder: Brachyura, which includes crabs and lobsters.
Feeding
Trapezia digitalis is considered a corallivorous crab, primarily feeding on coral polyps. These crabs are known to graze on the mucus secreted by corals, as well as on the polyps themselves. This feeding behavior is integral to the health of the coral reef ecosystem, as it helps to control the growth of algae and promotes coral growth.
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