Arthropoda IV - Malacostraca Flashcards
Malacostracan clades (4)
Euphausiacea - krill
Peracardia - amphipods & isopods
Stomatopoda - mantis shrimp
Decapoda -
Pancrustacea Ancestral Characteristics (3)
2 pair antennae
Biramous appendages
Nauplius larva (planktonic)
Malacostraca Appendages (19 pairs)
Head - 5 pairs
Antennae I & II
Mandibles
Maxillae I & II
Thorax - 8 pairs
Thoracopods: maxillipeds (variable #) for feeding and pereopods for walking
Abdomen - 6 pairs
Pleopods: biramous for swimming first 5
Uropods: biramous, form tail fan with the telson
Carapace
This is a covering of the head and thorax
Posterior growth of head exoskeleton to the turtle sclerite
Branchiostegites
This is a lateral flap of carapace that grows down the lateral side
It forms a gill chamber
Euphausiacea
Holopelagic
Incomplete branchiostegite
No maxillipeds
Thoracopods: biramous and highly setose, they form the filtering basket for feeding
Peracarida
These are the Amphipoda and Isopoda
Amphipoda have lateral compression
Isopoda have dorso-ventral compression
No carapace
1 pair of maxillipeds
Females have marsupium - for offspring brooding
Coxal plates form branchial chambers in Amphipods
Terrestrial Adaptations of Isopods
Avoidance of desiccation (seek humid microhabitats and waxes deposited in exocuticle) Excretion by diffusion of ammonia gas Gas exchange (folded exopods of pleopods and pseudotracheae) Closed marsupium (filled with fluid)
Subchelate appendage
Gnathopdods
Backward curving chelate appendage
Makes jack knife structure
Stomatopoda
5 pairs of maxillipeds
2nd pair of maxillipeds are for prey capture, defence and territorial disputes (they are raptorial appendages)
Spearers live in soft substrates and smashers live in rock crevices
Stomatopod eyes
These are the most complex eyes of any animal 12 different colour vision pigments Incredible depth focus About 160-degree rotation It is a compounds eye
