Hermit Crabs and Mole Crabs
Anomura
Classification
- Phylum: Arthropoda
- Subphylum: Crustacea
- Class: Malacostraca
- Superorder: Eucarida
- Order: Decapoda
- Infraorder: Anomura
Pronunciation
How to pronounce Anomura: /ænəˈmjʊərə/
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Images
Summary
Anomura is an infraorder of decapod crustaceans that includes hermit crabs and other unique forms. They have a notable evolutionary history marked by instances of carcinisation, which gives rise to crab-like body forms. Anomura can be recognized by their characteristic morphology and ecological roles in marine environments.
Physical Characteristics
Anomura exhibit a variety of forms, characterized by having ten pereiopods; however, the last pair is reduced in size and often hidden under the carapace for gill cleaning. This results in some individuals being recognized by the presence of only eight visible pereiopods.
Identification Tips
Look for the reduced last pair of pereiopods and a variety of body forms which distinguish them from true crabs.
Habitat
Anomura are primarily found in marine environments, ranging from shallow waters to deep-sea habitats.
Distribution
Anomura species are distributed globally in various oceanic regions, particularly in tropical and temperate zones.
Diet
Anomura are omnivorous, feeding on detritus, algae, and other organic materials available in their environment.
Life Cycle
The life cycle of Anomura typically includes a larval stage, after which they settle into their adult form, often undergoing changes in morphology as they mature.
Reproduction
Anomura reproduce by laying eggs, which are often carried by the females until they hatch. The reproductive habits can vary significantly among different superfamilies.
Predators
Anomura may fall prey to larger fish, seabirds, and various marine predators.
Ecosystem Role
Anomura play important roles in their ecosystems as scavengers and detritivores, contributing to the nutrient cycling and cleaning of marine habitats.
Economic Impact
Some Anomura species, such as hermit crabs, are harvested for food and as pets, impacting local economies and fishing practices.
Collecting Methods
- Hand collection
- Traps
- Netting
Preservation Methods
- Freezing
- Alcohol preservation
- Drying
Evolution
Anomura likely diverged from Brachyura during the Late Triassic period, with a fossil record indicating their presence dating back to this time. They are positioned within the clade Meiura, alongside true crabs.
Misconceptions
Misidentified as true crabs due to their common name including 'crab', whereas true crabs belong to a separate infraorder, Brachyura.
Tags
- Crustacea
- Decapoda
- Hermit Crabs
- Marine Biology