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Cyclodius ungulatus
H. Milne Edwards, 1834

Hoof-Clawed Reef Crab

Joshua Gaschk (2014)


Fact Sheet



Physical Description


Life History & Behaviour

Anatomy & Physiology

Evolution & Systematics

Biogeographic Distribution

Conservation & Threats

References & Links

Evolution & Systematics

Phylum – Arthropoda
  • Segmented bodies
  • Jointed limbs
  • Chitin exoskeleton
  • Tagmosis
Sub-Phylum - Crustacea 
  • Biramous limbs
  • Two sets of antennae
Class – Malacostraca
  • Coxa of antennae proximal to basis
  • Maxillula specialised for transport of food to mandible
  • Parts covered in fine hairs
Order – Decapod
  • Means Ten legs
  • zoea and megalopae larval stages
  • well developed exoskeleton around Cephalothorax 
Family – Xanthidae
  • Produce toxins
  • ‘Xanthid ring’
Genus – Cyclodius
  • Smooth carapace
  • Minimal setae on legs
  • Chelipeds rough with blunt tubercles
Species Cyclodius ungulatus
  • Palm well covered with tubercles compared to other genus

Brachyura is an extremely diverse taxa; approximately 10,000 species belong to the infraorder. Due to the complexity and wide range of organisms belonging to the taxa it is difficult to create a phylogenetic tree within the infraorder (Brosinget al. 2007).