Arthropoda
 

Etymology

  • From the greek name, for its distinctive jointed appendages, Arthron "joint" and Pous "Foot" or "Leg"

General

  • 85% of animal species described belong to Arthropoda
  • Over 1,000,000,134,000 species identified, found world-wide
  • Aquatic species includes Lobsters, Crabs, Hermit Crabs, Crayfish, Shrimps and Barnacles
  • Non aquatic species include Insects, Spiders, Scorpions 
  • Thought to have originated from Annelids

Defining Characteristics

  • Bilaterally symmetry (mostly) with a renewable chitinous exoskeleton, a supporting structure on the outside of the body
  • Two main body types in the aquatic realm: shrimp like and crab like
  • Segmented bodies divided into 2 or 3 sections, known as Tagmosis
  • Distinctive jointed appendages, may be modified in a number of ways to form antennae, mouthparts and reproductive organ
  • Protostomes, develops mouth before anus
  • Most paossess a straight gut with an anus, body cavity has a true coelom
  • Do have a nervous system including a brain and ganglia
  • Do possess a respiratory system in the form of trachea and spiracles (mostly)
  • Do possess a open or lacunar circulatory system with a simple heart, on or more arteries, and no veins (mostly) 

Body    

  • Body possess an external skeleton (mostly), Stiff cuticle, usually a hard outer. Body covering made of chitin and proteins, form an exoskeleton which may or may not be stiffened further with calcium carbonate, like jointed armour.
  • Molting: Shedding the exoskeleton to grow, a crucial part of development.
  • Segmented bodies with various patterns of segmented fusion (tagmosis) to form integrated units (heads and abdomen)
  • Body possesses 3 – 400+ pairs of jointed legs 
  • Molting: Shedding the exoskeleton to grow, a crucial part of development.

Reproduction / Life Cycle

  • Sexual Reproduction: Most common, with separate sexes and internal fertilization, although aquatic species can use external fertilization.
  • Asexual Reproduction: Some can reproduce via parthenogenesis, where unfertilized eggs develop (e.g., honey bee drones).
  • Sperm Transfer: Can involve direct transfer or indirect methods like spermatophores (sperm packets).
  • Metamorphosis: The transformation from larva to adult, allowing different stages to exploit different resources.
  • Can take up to 12 stages to metamorphose into adult
  • Normally sexual, involving capulation and gonochoristic


Feeding

Feed on everything

 

Victorian Species

 

CLASS:  Pycnogonida

 

Scientific Name:         Pallenella ambigua                      Scientific Name:         Nymphon sp. 

Common Name:         Sea Spider                                   Common Name:         Sea Spider

           

Picture taken at Devils Dropoff on 23.02.2013                           Picture taken at Blairgowrie Pier on 10.11.2021

 

CLASS:  Malacostraca 

 

Scientific Name:   Jasus edwardsii                                                         Scientific Name:   Galathea australiensis

Common Name:   Southern Rock Lobster                                             Common Name:   Straited Squat Lobster

Jasus edwardsii - Southern Rock Lobster                  Galathea australiensis - Straited Sqaut Lobster

Photo at Boarfish Reef on 10.05.2010                                                                  Photo at Blairgowrie Pier on 03.09.2019

 

 

Scientific Name:   Paguristes frontalis                      Scientific Name: Strigopagurus strigimanus           Scientific Name:   Lophopagurus nanus

Common Name:   Common Hermit Crab                  Common Name:   Stridulating Hermit Crab            Common Name:   Pagurid Hermit Crab

Paguristes frontalis - Common Hermit Crab          Strigopagurus strigimanus - Stridulating Hermit Crab              Lophopagurus nanus - Pagurid Hermit Crab

Photo at Blairgowrie Pier on 15.04.2022                               Photo at Blairgowrie Pier on 17.04.2013                           Photo at Blairgowrie Pier on 03.09.2019

 

Scientific Name:   Pagurixus handrecki

Common Name:   Clarrie’s Hermit Crab

Trypaea australiensis - Yabby, Australian Ghost Shrimp

Photo at Mornington Pier on 03.10.2020

 

Scientific Name:   Engaeus sp.

Common Name:   Australian Burrowing Crayfishes

Engaeus sp. - Australian Burrowing Crayfishes

Photo at Sweetwater Creek on 11.09.2022

 

Scientific Name:   Trypaea australiensis  

Common Name:   Yabby, Australian Ghost Shrimp

Trypaea australiensis - Yabby, Australian Ghost Shrimp

Photo at Barwon Heads on 01.10.2019

 

 

 

Scientific Name:   Halicarcinus ovatus

Common Name:    Three-pronged Spider Crab

Halicarcinus ovatus - Three-pronged Spider Crab

Photo at Blairgowrie Pier on 02.07.2024

 

Scientific Name:   Trigonoplax longirostris

Common Name:   Crab

Trigonoplax longirostris - Crab

Photo at Blairgowrie Pier on 31.10.2022

 

FAMILY: Leucosiidea (Purse Crabs)

 

Scientific Name:   Ebalia intermedia

Common Name:   Smooth Nut Crab

Ebalia intermedia - Smooth Nut Crab

Photo at Franskton Pier on 14.06.2021

 

FAMILY: Majidae - Spider & Decorator Crabs

• Family of crabs comprising 200 marine species in 52 Genera
• Their carapace is longer than it is broad, and forms a point at the front
• The legs can be very long on some species, eg spider crab
• Exoskeleton is covered with bristles to which the crab attaches algae and other items to act as camouflage.

 

 

Scientific Name:         Leptomithrax gaimardii                   Scientific Name:      Microhalimus deflexifrons                    Scientific Name:  Naxia aurita

Common Name:         Giant Spider Crab                          Common Name:      Decorator Crab                                    Common Name:  Golden Decorator Crab

 

          

Photo at Rye Pier on 22.05.2020                                                 Photo at Blairgowrie Pier on uknown date                                         Photo at Blairgowrie Pier on 02.10.2021

 

 

 

 

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