Arthropoda Lab

Phylum Anthropoda

Subphylum Mandibulata 

Class Crustacea

External anatomy:
cephalon, thorax, cephalothorax, abdomen, appendages, antennae, antennules, mandibles, maxillae, maxillipeds, carapace, compound eyes, rostrum, thoracopods, pereopods, pleopods, uropod, telson, chelipeds, tergum, scutum, cirri
Internal anatomy:
gills, cardiac stomach, esophagus, pyloric stomach, antennal (green) gland,
intestine, aorta, ventral nerve cord, mandibular muscle
“Fiddler crab anatomy” By Christopher Thomas Under Creative Commons Attribution-Share Alike 3.0 Unported

Image result for daphnia diagram

“Daphnia” By E Ray Lankester Under  public domain
  1. As you can see in the above drawings,crayfish and shrimp have many similar appendages. Some of these include their antennae, abdomen, carpace (shell), antennules, swimmerets, uropods, telson and walking legs. Crabs also share some of these features like the walking legs, antenna, carapace and chelipeds. Crayfish and shrimp are much more similar to each other in regards to body type and anatomy than to a crab.
  2. If you inspect the area between the last two pair of legs on a crayfish, females have an opening to receive and store the sperm in this spot. Also, if you see eggs or baby crayfish then you definitely have a female crayfish.
  3. Some small crustaceans are able to exchange gases through the process of diffusion directly across the body surface. Because they are so small, their blood is close enough to the surface to directly exchange gases.Larger aquatic crustaceans mostly use gills for respiration. The gills are feathered surfaces that contain membranes that bind to dissolved oxygen in the water as water passes over. The oxygen then moves from the gills into the blood of crustaceans in the circulatory system so that the oxygen can be delivered to the rest of the body.
  4. Crabs, crayfish and shrimp all have antennae which are used as their primary sensory organs. All of these crustaceans also have good eyesight so that they can see their predators and prey.
  5. The cirri of the barnacles have sensory hair on them and they filter the water collecting plankton for the barnacle to eat.
  6. The decapod anntenal gland is the excretory gland in most crustaceans. In many of the crustaceans this gland is located in their head.
  7.  There is only one kind of crayfish that is known to reproduce without a male and a female present.  In some shrimps, the adults start out as males and later develop into females. There are also a few species that keep both their male and female reproductive structures.

Class Myriapoda

  • Order Diplopoda
  • Order Chilopoda

Class Insecta

  • Order Odonata (Dragnoflies)
  • Order Isoptera (Termites)
  • Order Orthoptera (Grasshopper, Katydid, Cricket)
  • Order Hemiptera (TrueBugs, Stink Bugs)
  • Order Coleoptera (Beetle)
  • Order Diptera (Flies)
  • Order Siphonaptera (Fleas)
  • Order Lepidoptera (Butterflies and Moths)
  • Order Hymenoptera (Ants, Bees, Wasps and Sawflies)

External anatomy

head, thorax, abdomen, antennae, compound eye, coxa, trochanter, femur, tibia, tarsus, ovipositor, spiracles, forewing, hindwing, cercus

mouthparts: mandibles, clypeus, labrum, maxilla, palps

Internal anatomy

Foregut (pharynx, esophagus, crop), midgut (stomach), hindgut, gastric ceca, malphighian tubules, trachae (more difficult)

  1. The main difference between grasshoppers and crickets is their antennae and their diet. Crickets tend to have long antennae while grasshoppers have short ones. Also grasshoppers mostly only eat grass but crickets are likely to eat animal matter.
  2. Caterpillars and beetles have mandibles which they use for feeding and eating while flies and butterflies siphon and suck their food by using a long tube.
  3. Insects are able to exchange oxygen and carbon dioxide between their tissues and the air by a system of air-filled tubes called tracheae. The tracheae open to the outside through small holes called spiracles. This is different from gas exchange in crustaceans because they get their oxygen from the water and they use gills.
  4. The Malpighian tubule system is a type of excretory and osmoregulatory system found in some insects. It consists of branching tubules that go from the alimentary canal to releasing the wastes from the organism in the form of solid nitrogenous compounds and calcium oxalate.
  5.  Insects will either take part in hemimetabolous development or holometabolous development. In hemimetabolous development, the insect will undergo an incomplete or partial metamorphosis. In holometabolous development the insect will undergo a complete metamorphosis which includes a pupal stage between the larval and adult forms. The order Lepidoptera undergoes holometabolous development while the orders Odonata and Orthoptera undergoes hemimetabolous development.

Subphylum Chelicerata

Class Merostomata

Class Arachnida

  • Order Acari (mite)

  • Order Araneae (Spider)

  • Order Scorpiones (Scorpions)

  • Order Amblypgi (Tailless Whip Scorpions)

External Anatomy:

Prosoma, opisthosoma, pedicel, book gills, pedipalps, chelicera, fangs, walking legs, mouth, carapace, telson, maxilla, sternum, epigynum (epigastric furrow), spiracle, spinnerets, main eyes, secondary eyes, trochanter, femur, patella, tibia, tarsus


“Ixodesfemale” By Sonenshine, DE: Biology of Ticks, 2 volumes: Oxford University Press, New York, Oxford, 1991 Under  Creative Commons Attribution 3.0 Unported

“Spider Anatomy” By  Pbroks13 Under CC BY 3.0