Crustaceans (part 2)

What are the Classes of Crustacea

-Branchiopoda
-Cephalocarida
-Cirripedia
-Copepoda
-Malacostraca
-Ostracoda
-Remipedia

Malacostraca body structure

-Calcified exoskeleton
-Cephalon/Thorax/Abdomen/Telson
-Cephalothorax
-5 segments in the head
-8 segments thorax
-6 segments abdomen

Malacostraca physiology

-Highly centralised nervous system
-Large brain near the eye
-Green glands in the second antennae
-2 chambered stomachs with a gastric mill

What is the function of the green gland

Used as osmoregulatory regulator and and as an excretory function

What does the green gland excrete

Disposal of nitrogenous wastes

What are the 3 subclasses of Malacostraca

Phyllocarida
-Oldest known crustacean (1 living group)
Hoplocarida
-Only extant members are in the order Stomatopoda
Eumalacostraca
-All others

What are the types of hunting Stomatopoda use? and which prey they hunt?

Spearers
-Fish
Clubbers
-Molluscs/crustaceans

What are the 3 Superorders of Eumalacostraca

Syncarida
-Freshwater
Peracarida
-Isopods and amphipods
Eucarida
-Crabs/Shrimps

What are the 2 order of Peracarida?

Isopoda
-Dorso ventrally compressed
Amphipoda
-Laterally compressed

Number of marine/freshwater/terrestrial Isopoda?

Marine
-4500
Freshwater
-500
Terrestrial
-5000

What do Isopoda use for gaseous exchange?

Pleopods

What does the paper "Impact of a mouth parasite in a marine fish differs between geographical areas" show?

This study compared the influence of Ceratothoa italica (parasitic isopod) between to population of Lithognathus mormyrus, where one population is in a protected while the other is in a exploited zone.

Findings of "Impact of a mouth parasite in a marine fish differs between geographical areas"

It could be seen that the exploited population was being more significantly affected by the parasite compared to the protected population. Damaging the growth rate of exploited the population. This study hypothesised the more exploited an area is the more parasitism there will be.

Citate "Impact of a mouth parasite in a marine fish differs between geographical areas"

Sala-Bozano et al., 2012

Amphipoda body structure

-Laterally compressed
-No carapace
-Mostly marine
-Hyperiids (planktonic) and gammarids

What type of feeding they have?

Detritivores/Scavengers

What some hyperiids (Phronima) live in?

Barrels
-constructed from salps and other zooplankton

What are 2 Order of Eucarida?

Euphausiacea
-Krill
Decapoda
-Crabs, lobster, shrimp

Euphausiacea

-Generally up to a few cm long
-All marine
-Large exposed gills ventilated by thoracic appendages

How is the larval stage in Euphausiacea

Vertically separated
-Ontogenetic Vertical Migration

Decapoda body structure

-Cephalothorax always covered by carapace (branchial chamber)
-Five pairs of pereopods
-First pair if pereopods usually with claws (chelipeds)

How does water enter in shrimps for respiration?

Through the walking legs

How to decapods and stomatopods use as respiratory pigment?

Hemocyanin

How are the clogging of the gills prevented in Crustacea?

-Setae on limbs act as filters
-Cleaning of gills
-Periodically gill bailer reverse flow

When do Decapod reproduce?

After moulting

How do Decapoda attract mates?

Pheromones

In which species fertilisation internal happen?

Brachyurans (crabs)

Where are Spermatophores deposited in Decapoda?

Sternal surface

What type of stages do marine Decapoda hatch?

Protozoea and Zoea

Malacostracan chromatophore

Branched but non-contractile pigment granules of several colours

What are the 2 type of colour changes in Malacostracan chromatophores?

Morphological colour change
-Long term
-Loss or formation of pigments or chromatophores
Physiological
-Rapid change in colour

What are the triggers identified for pigment aggregation/dispersion?

-Light
-Circadian timing
-Temperature
-Exercise
-Background
-Tide

What does the paper "Color change and camouflage in juvenile shore crabs Carcinus maenas" show?

How juvenile shore crabs can coloration to blend into different backgrounds, enhancing their camouflage and reducing predation risk

What are the findings of "Color change and camouflage in juvenile shore crabs Carcinus maenas"

Background matching
-They were able to adjust their brightness to match their backgrounds
Predator vision
-This camouflaged decreased predator attacks
Limited changes
-Not much change in red and green backgrounds

Citate "Color change and camouflage in juvenile shore crabs Carcinus maenas"

Stevens, Lown and Wood, 2014

What factors affects their hunting strategies?

Prey availability

What does the paper "Home range of European lobster (Homarus gammarus) in a marine reserve: implications for future reserve design" show?

Investigates the movement patterns and home ranges of European lobsters within marine reserves

Citate "Home range of European lobster (Homarus gammarus) in a marine reserve: implications for future reserve design"

Moland et al., 2011

common decapods in British rockpools

-Prawns (Palaemon)
-Broen shrimp (Crangon crangon)
-Velvet swimming crab (Necora puber)
-Shore crab (Carcinus maenas)
-Brown crab (Cancer pagurus)
-Broad clawed procelain crab (Porcellana platycheles)