---
title: Crabs (Brachyura)
scientific_name: Brachyura
common_name: Crabs
rank: Infraorder
published: 2024-11-19T18:41:51.573Z
updated: 2026-08-03T20:52:46.901Z
tags: Crabs, Brachyura, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs
---

# Crabs (*Brachyura*)

## Quick facts

- **Rank:** Infraorder
- **Scientific name:** Brachyura
- **Body shape:** Invertebrate - Not a fish - coral, mollusc, crustacean, echinoderm and other invertebrate groups.
- **Species listed here:** 28

## How to recognise this group

- broad, flattened body covered by hard carapace
- small abdomen tucked under body
- ten legs, first pair usually forming pincers
- walking sideways or forwards on bottom or reef

Crabs (Brachyura) are crustaceans distinguished by a broad, flattened cephalothorax encased in a hard carapace, and a small abdomen tucked tightly beneath the body. All members possess ten legs, with the front pair typically forming strong pincers (chelae) used for defense, feeding, and courtship. Carapace width varies significantly among species, from less than 1 cm (0.4 in) in the smallest forms to over 20 cm (8 in) for larger species found on Red Sea reefs. Many species display cryptic coloration, with carapaces patterned in shades of brown, grey, green, red, or orange to blend with their surroundings.

Crabs inhabit diverse marine environments, including intertidal zones, sandy flats, coral reefs, and rubble fields, living from the surface down to at least 100 m (330 ft) depth. Primarily scavengers, they consume algae, detritus, and carrion, though many also actively hunt mollusks, worms, and small fish, using smaller mouthparts to shred food before ingestion. Most species walk swiftly, either sideways or forwards; however, some families, such as swimming crabs, feature flattened hind legs adapted for propulsion through water. A notable trait is their ability to regenerate lost limbs through autotomy during molting. Divers frequently encounter crabs hidden in reef crevices, under rocks, or camouflaged on sandy bottoms.


## Species (28)

- [Actaeodes tomentosus (Actaeodes tomentosus)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/actaeodes-tomentosus)
- [Andreossy's Coral Crab (Cymo andreossyi)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/andreossys-coral-crab)
- [Banded Coral Crab (Tetralia cinctipes)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/banded-coral-crab)
- [Bandit Coral Crab (Tetralia nigrolineata)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/bandit-coral-crab)
- [Black-fingered Coral Crab (Cymo melanodactylus)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/black-fingered-coral-crab)
- [Boxer Crab (Lybia caestifera)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/boxer-crab)
- [Brown Guard Crab (Trapezia digitalis)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/brown-guard-crab)
- [Chlorodiella barbata (Chlorodiella barbata)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/chlorodiella-barbata)
- [Chlorodiella cytherea (Chlorodiella cytherea)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/chlorodiella-cytherea)
- [Common Box Crab (Calappa bicornis)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/common-box-crab)
- [Decorator Spider Crab (Camposcia retusa)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/decorator-spider-crab)
- [Electra Round Crab (Etisus electra)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/electra-round-crab)
- [Elegant Reef Crab (Lophozozymus pulchellus)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/elegant-reef-crab)
- [Harlequin Swimming Crab (Lissocarcinus orbicularis)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/harlequin-swimming-crab)
- [Horrid Elbow Crab (Daldorfia horrida)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/horrid-elbow-crab)
- [Nobili's Reef Crab (Neoliomera nobilii)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/nobilis-reef-crab)
- [Orchid Spider Crab (Hoplophrys oatesii)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/orchid-spider-crab)
- [Red Reef Crab (Liomera rubra)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/red-reef-crab)
- [Red-spotted Guard Crab (Trapezia tigrina)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/red-spotted-guard-crab)
- [Reef Box Crab (Calappa hepatica)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/reef-box-crab)
- [Rusty Guard Crab (Trapezia bidentata)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/rusty-guard-crab)
- [Sea Urchin Crab (Echinoecus pentagonus)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/sea-urchin-crab)
- [Showy Xanthid Crab (Pseudoliomera speciosa)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/showy-xanthid-crab)
- [Spiny Rock Crab (Actaea polyacantha)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/spiny-rock-crab)
- [Splendid Round Crab (Etisus splendidus)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/splendid-round-crab)
- [Spotted Coral Crab (Quadrella maculosa)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/spotted-coral-crab)
- [Spotted Guard Crab (Trapezia guttata)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/spotted-guard-crab)
- [Wire Coral Crab (Xenocarcinus tuberculatus)](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/wire-coral-crab)

---

*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs)*
*Updated: August 3, 2026*