Subphylum: Chelicerata

General characters:Body: Prosoma (6) and Opisthosoma (12) A pair of chelicerae on the 1st prosomal segment One pair of pedipalps + 4 pairsof walking

legs Three classes:1. Arachnida2. Merostomata3. Pycnogonida

SP: Chelicerata, Class Merostomata

Limulus limus – horseshoe crab

SP Chelicerata, Class Merostomata

SP: Chelicerata, Class Pycnogonida

SP Chelicerata, Class Arachnida, Order Araneae

General characters:Includes: scorpions, spiders, ticks and mites All areterresterial No antennae or true jaws Head is not distinct The body: prosoma (6) + opisthosoma Respiration by: 1. lung books or tracheae in terresterial forms2. through skin in parasitic forms3. gill books in aquatic forms Excretion by Malpighian tubules or coxal glands Open Circulatory system Separate sexes. Viviparous or Oviparous Mostly carnivorous but some are ectoparasites

Class: Arachnida

Classification

of Arachnida

O: pseudo-

Scorpionidea

O:

Solifuga

O: Acarina

O:

Ara

nea

O: Scorpionidea

O: Scorpionidea

Terrestarial Body: pro-, meso- and meta- soma Prosoma: one pair of chelicera, one pair of pedipalps, 4 pairs of walking legs Mesosoma: 6 segments A pair of pectins on the 2nd segment of mesosoma Respiration: by 4 pairs of lung books Viviparous eg Buthus quinquestriatus (scorpion)

Lethally Poisonous Scorpions

Centruroides exilicauda

Leiurus quinquestriatus

Class Arachnida, Order ScorpionidaPaninus imperator (Emperor scorpion)

O: Araneida

Terrestarial Body: pro-, and opistho- soma Prosoma: one pair of chelicera (non-chelate), one pair of pedipalps (non-chelate), 4 pairs of walking legs Opisthosoma: 12 segments Spinnerets: 2-4 pairs Respiration: by lung books Oviparous eg Lycosa ferox (wolf spider)

SP Chelicerata, Class Arachnida, Order Araneae

Spinnerets

Anatomy of spider

Regional Poisonous Spiders

Lactrodectus mactans

Loxosceles reclusa

Brown Recluse Bite Victom

Tan Tarantula

Argiope aurantia

Aphonopelma anax

Golden Orb Spider/Garden Spider

Class Arachnida, Order Opiliones

Class Arachnida, Order Solifugae

Eremobates sp

Class Arachnida: Ticks and mites

• No external division or segmentation• Found almost everywhere• Chiggers: feed on dermal tissues of

humans• Dust mites: can cause allergies• Hair follicle mites: infect most of us,

but we are unaware of it• Ticks spread disease: Rocky mountain

fever and Lyme’s disease

Class Arachnida, Order Acari

Dermacentor variabilis American dog tick

Rhipicephalus sanguineus Brown dog tick

Rocky mountain spotted fever

Class Arachnida, Order AcariIxodes scapularis Deer tick

Lyme disease

Class Arachnida, Order Acari

Class Arachnida, Order AcariEutrombicula alfreddugesi Chigger

Sarcoptes scabiei scabies mite

Class Arachnida, Order AcariDermatophagoides spp Dust mite

Class Arachnida, Order Amblypygi

Phylum Mollusca

CHARACTERISTICSCHARACTERISTICS Second largest phylum in the animal kingdom (80000 living species and 40000 fossil species) Soft bodied animalsBody: head, foot and visceral hump Microscopic to macroscopicThey include chitons, snails, slugs, clams, oysters, cuttlefish, squids, octopods, scaphopods, ……. Slow to active organisms Coelomate, triploplastic, unsegmented

Second largest phylum in the animal kingdom (80000 living species and 40000 fossil species) Soft bodied animalsBody: head, foot and visceral hump Microscopic to macroscopicThey include chitons, snails, slugs, clams, oysters, cuttlefish, squids, octopods, scaphopods, ……. Slow to active organisms Coelomate, triploplastic, unsegmented

Terrestrial, freshwater, or marine environments

Occur in a wide variety of environments Have different modes of nutrition Bilateral symmetry, torsion and coiling in

gastropods True coelom is reduced Skin is soft and often secrets the exoskeleton

or the shell Respiration by one to many gills (ctenidia) Radula in most molluscs Circulatory system of open type (except

cephalopods)

Blood contains haemocyanin and amoebocytes The nervous system is composed of a nerve

ring around the oesophagus and two pairs of nerve cords

Sense organs include tentacles, eye spots, statocysts in foot and osphradia beside gills

Excretion by a pair of u- shaped metanephridia Molluscs are unisexual (dioecious) but some

are hermaphrodite (monoecious) Fertilization is mostly external and rarely

internal Development is direct (no larva) or indirect

through free swimming trochophore and/or veliger larvae

GENERAL BODY PLANGENERAL BODY PLAN Head

Ventrally located muscular foot

Dorsally located visceral mass

Mantle / pallium – for shell/spicule secretion

Radula (except for bivalves)

Complete digestive tract

Gonads in visceral mass

Monoecious or dioecious

Head

Ventrally located muscular foot

Dorsally located visceral mass

Mantle / pallium – for shell/spicule secretion

Radula (except for bivalves)

Complete digestive tract

Gonads in visceral mass

Monoecious or dioecious

• Subphylum Conchifera: with 1 shell; (-) spicules1. Class Gastropoda2. Class Bivalvia3. Class Cephalopoda4. Class Scaphopoda5. Class Monoplacophora

• Subphylum Aculifera: with multiple shell plates; (+) spicules1. Class Polyplacophora2. Class Aplacophora

• Subphylum Conchifera: with 1 shell; (-) spicules1. Class Gastropoda2. Class Bivalvia3. Class Cephalopoda4. Class Scaphopoda5. Class Monoplacophora

• Subphylum Aculifera: with multiple shell plates; (+) spicules1. Class Polyplacophora2. Class Aplacophora

CLASSIFICATIONCLASSIFICATION