Download Phylum: Mollusca

ZOOLOGY
RNDr. Oldřich Sychra, Ph.D.
Doc. MVDr. Jiří Klimeš, CSc.
Department of Biology and Wildlife Diseases
VFU Brno
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Phylum: Rotifera
Phylum: Rotifera
mikroscopic, planctonic
Spiny-headed worms
(Acanthocephala)
• rotifers adapted to parasitism
• 1150 species
• endoparasites of GIT - fish, waterfowl etc.
• proboscis, tegument, GIT lost
• gonochorists,
• larvae - acanthor, cystacanth
• intermediate hosts - crustaceans, beetles
Phylum: Mollusca
Phylum: Mollusca
50000 species; head, foot, visceral mass
with mantle, which encloses the mantle cavity
with gills or lungs; it secretes the shell
(calcareous with conchiolin)
Circulatory system open or closed
NS: ganglia
excretion: metanephridia
GIT: radula - rasping organ
metanephridia
head-food portion
cross section
Phylum: Mollusca
Class: snail & slugs (Gastropoda)
• 40000 species; body asymmetrical, usually in a coiled shell (uncoiled
or absent in some); herbivorous, carnivorous, planktonic feeders
• Repro.: hermafrodites (proteandric); direct (no larva)
or indirect development (larva veliger)
Important as intermediate hosts of flukes and as seafood (abalone)
Prosobranchiata
mostly marine
Opisthobranchiata
sea slugs, sea butterflies
Pulmonata: terrestrial or limnic
Roman snail African land snail
(Achatina)
rock snail
applesnail
limpet
sea hare
abalone
pond snail
cone shell
grove snail
cowry
slug
ramshorn snail
scallop
Phylum: Mollusca
Class: mussels (Bivalvia)
9450 species; body laterally compressed, enclosed in two valves,
with dorsal hinge; head reduced, foot usually wedge shaped;
mostly sedentary filter feeders
sexes usually separate, indirect development
larva
larva
Imporatnt as seafood; pearl production
glochidium
Giant clam (Tridacna)
length: 1,5 m, weight: 225 kg
veliger
oyster
blue mussel
swan mussel
pearl oyster cockle
painter´s mussel
freshwater pearly mussel
Phylum: Mollusca
Class: squids & octopuses (Cephalopoda)
550 species; shell often reduced or absent;
active predators – chamber eyes; radula and beak; arms or tentacles;
foot modified into siphon (= reactive movement); chromatophores
circulatory system closed
NS: nervous system centralized to form a brain
Repro.: gonochorists, internal fertilization; no larvae
(hectocotylus arm – spermatophore), maternal care
Imporatnt as seafood.
Giant squid - 18 m; 450 kg
Nautilus pompilius
cuttlefish (Sepia officinalis)
squid (Loligo)
Octopus
Phylum: segmented worms (Annelida)
Phylum: segmented worms (Annelida)
15000 species
homonomous metamerism
body cavity: coelom (hydrostatic skeleton)
epidermis: chitinous setae
circular & longitudinal muscles
circulatory system closed
NS: ladder-like
ES: metanephridia
R: asexual, sexual
direct or indirect
development - larva trochofora
food – predators, ectoparasites;
saprotrophs, decomposers
= GIT: chloragogen tissue
(„liver“), typhlosole
(increasing intestine surface area)
blood vessels
ventral nerve cord
pair of coelomic
compartments
nonchitinous cuticle
with chitinous setae
Phylum: segmented worms (Annelida)
Class: marine worms (Polychaeta)
10000 species; pelagic or sessile (calcareous tubes);
most segments with parapodia bearing tufts of many setae & gills
gonochorists
larva trochofora
Samoan
palolo worm
Phylum: segmented worms (Annelida)
Class: Clitellata
protandrous hermafrodites – prevention of self-fertilization; no larva
clitellum – glandular section that secretes (1) slime for transport of
sperms and (2) viscid sac in which the eggs are deposited (cocoon)
Subclass: earth & freshwater worms (Oligochaeta) - 3000 species;
Important as decomposers, food of fishes; paratenic hosts of parasites
Lumbricus terrestris
vesiculae seminales
– own sperm
receptaculum seminis –
mate´s sperm
Tubifex tubifex
Phylum: segmented worms (Annelida)
Class: Clitellata
Subclass: leeches (Hirudinea)
2000 species; freshwater, terrestrial
predators, ectoparasites (oral & posterior suckers,
hirudin with a blood anticoagulant property)
Piscicola geometra - transmission of fish protozoan infections
„medicinal leech“
(Hirudo medicinalis)
Phylum: roundworms (Nematoda)
Phylum: roundworms (Nematoda)
BILATERIA – TRIBLASTICA
PROTOSTOMIA
Superphylum ECDYSOZOA
♂
30 000 species
free-living (aquatic, terrestrial) & parasitic,
body elongated vermiform, body cavity pseudocoel
Epidermis with collagenous noncellular cuticle
(sometimes molted = ecdysis)
Muscles only longitudinal (thrashing, not crawling movements)
GIT: digestive tract complete (mouth-to-anus)
excretion: protonephridial canals or renettes (gland cells)
NS: ganglia, nerve ring and cords
R: gonochorists, rarely hermafrodites or partenogenesis,
Indirect developmnent: 3-5 juvenile stages separated by moulting
with (biohelminths) or without intermediate host (geohelminths)
♀
Phylum: roundworms (Nematoda)
Class: Adenophorea = Aphasmida
Order: Trichocephalida = Enoplida
Trichuris = Trichocephalus - geohelminth
Trichuris egg
trichina worm or porkworm (Trichinella spiralis) biohelminth
juveniles in muscle, adults in intestine
rat-pig (human) or (now more frequently) wild boar,
wild carnivores, dog (human)
excretion: only
gland cells
Phylum: roundworms (Nematoda)
Class: Secernentea = Phasmida
Order: hookworms (Strongylida)
gapeworm (Syngamus trachea)
Ancylostoma duodenale
♂
excretion: protonephridialcanals
♀
Order: Rhabditida
Caenorhabditis elegans – experimental model – 3 Nobel prices
hermafrodite, eutely = constancy in number of cells/nuclei
Phylum: roundworms (Nematoda)
Order: Ascaridida – geohelminths
Large roundworm of human
(Ascaris lumbricoides)
pinworms (Oxyuris, Enterobius)
Enterobius vermicularis
organ migration – substitution for the absent
intermediate host, autoinfection impossible
No organ migration; autoinfection
possible (anal pruritus in children)
4-6 hours
2-3 weeks
Phylum: roundworms (Nematoda)
Order: Spirurida - biohelminths
Wuchereria bancrofti – elephantiasis,
intermediate host - mosquitos; larvae = microfilariae
(filarial worms)
Guinea worm (Dracunculus medinensis)
intermediate host – copepods
eradicated in Asia
Phylum: Arthropoda
Phylum: Arthropoda
about 1.000.000 species
vertebrates
47.000
invertebrates
without
arthropods
150.000
Viruses
1.000
arthropods
without insects
120.000
insects
900.000
Procaryotes
4.800
Fungi
69.000
Algae
26.900
plants
248.400
Protozoa
30.800
Phylum: Arthropoda
cladogram
Hexapoda
Crustacea
Myriapoda
Chelicerata
Trilobites (Trilobitomorpha)
• heteronomous metamerism and tagmatization
• jointed (segmented) appendages
head thorax
abdomen
hypotethic
ancestor
biramous
uniramous
coxa
cephalothorax
Chelicerata
trochanter
femur
Crustacea
trunk
patela
tibia
Myriapoda
tarsus
Hexapoda
• sclerotised exoskeleton (chitin)
• growth – moulting (ecdysis)
- controlled by hormone ecdysone
• open circulatory system – hemolymph, dorsal heart
• NS: ganglionic ladder-like – ventral nerve cord
M. Malpighi
(1628-1694)
• excretion
modified metanephridia (paired)
 antennal, maxillar glands (Crustacea)
 coxal glands (spiders)
Malpighian tubules (insects, spiders)
• respiration
 body surface (small mites, small crustaceans)
 gills (crustaceans)
 book lungs (spiders)
 tracheae (insects, spiders, myriapods)
Subphylum: Chelicerata
Former class: Merostomata – subclass: Xiphosurida
5 species; „living fossils“
Horseshoe crabs (Limulus spp.) – littoral, some appendages with gills
Limulus test detects the presence of bacterial endotoxin in intravenous
solutions.
larva (trilobite-like)
Class: Arachnida – spiders, scorpions, mites
about 80.000 species
body tagmata - cephalothorax and abdomen
head appendages - chelicerae and pedipalps (claws and fangs)
cephalothorax bears four pairs of legs
spinning glands
predators - venom to kill their prey (black widow)
Subphylum Chelicerata
Class Arachnida – spiders, scorpions, mites
spiders (Araneida)
• fang-like chelicerae, poison glands
• silk glands (liquid that hardens into a firm silk thread)
• extracorporal digestion
• pedipalps greater in males (sperm transfer)
• direct development (no larva)
Tarantulas or bird spiders
(Orthognatha)
spiders (Labidognatha)
Subphylum Chelicerata
Class Arachnida – spiders, scorpions, mites
scorpions (Scorpionida)
• tropical, subtropical, arid regions, nocturnal,
• predaceuous – pedipalps (prey capture), chelicerate (feeding)
• stinger on the last abdominal segment
• viviparous, mother´s care
• captivity, age up to 15 years
pedipalp
chelicerae
Subphylum Chelicerata
Class Arachnida – spiders, scorpions, mites
Ticks and mites (Acari, Acarina)
Highest diversity (40000 species) and importance, small, in soil,
water, parasites, allergies, storage and agricultural pests
science – acarology
gnathosoma
idiosoma
prosoma
opisthosoma
proterosoma
hysterosoma
Indirect development
larva (3 pairs of legs)
nymph (4 pairs of legs) – proto-, deut(er)o-, tritonymph → imago
Castor-bean tick (Ixodes ricinus)
Family: „hard ticks“ (Ixodidae)
• hypostome (modified mouthparts)
• sexual dimorphism (dorsal shield), only ♀ sucks blood
• vector of endemic infectious diseases (encephalitis, Lyme
disease, tularemia)
male
female
hypostome
Castor-bean tick (Ixodes ricinus)
a three-host tick:
1) larva („mice“)
2) nymph (hare)
3) imago (deer, dog, man)
female
Red (roost) mite (Dermanyssus gallinae)
ectoparasite of birds (poultry)
nocturnal - sucks blood at night
in crevices by day
vector of many infectious agents
Varroa destructor (formerly V. jacobsoni)
• most important bee parasite
• sucks hemolymph
• has spread from South Asia
• sexual dimorphism (♀ > ♂)
Acarapis woodi
parasite, tracheae of bees
Hair-follicle mite (Demodex spp.)
• smallest mites (100 µm), in domestic animals, man
• hair follicles, sebaceous glands → easy diagnosis
• in immunocompromised dogs, „red mange“
Itch mite (Sarcoptes scabiei)
• cause of scabies or sarcoptic mange of animals, man
• burrows in epidermis, intense pruritus
• proof in multiple skin scrapings → difficult diagnosis
scaly leg in fowls
Many other genera of veterinary importance:
Knemidokoptes, Notoedres, Psoroptes, Chorioptes,
Otodectes
Storage pests
Storage mites (Acaridae)
Acarus siro
Tyrophagus spp.
Glyciphagus destructor
Allergies
House dust mite
(Dermatophagoides farinae) etc.
Beetle mites (Oribatida)
Free-living
intermediate hosts of the tapeworms Moniezia spp. etc.
Subphylum Myriapoda
body tagmata - head and trunk, all appendages uniramous;
about 13.000 species
Class Dipopoda - millipedes
body almost cylindrical; usually two pairs of legs
to a somite; usually herbivorous
Julus
Class Chilopoda - centipedes
dorsoventrally flattened body;
1 pair of legs on each segment;
usually carnivorous predators
Lithobius
Scolopendra
Subphylum Crustacea - Aquatic mandibulates
about 40.000 species
body tagmata - cephalothorax and abdomen.
head appendages - 2p.antennae, 1p. mandibles, 2p. maxillae.
biramous appendages
Development: direct
Class Maxilopoda
zoea
(a) planktonic: copepods
or larva nauplius or zoea
nauplius
Class Branchiopoda
fairy shrimp
brine shrimp
clam shrimps tadpole shrimps
(b) parasitic: fish lice,
(c) sedentary barnacles
(c)
water fleas
Class Ostracoda
– ostracods
(a)
(b)
often microscopic forms that drift as plankton in oceans or in lakes
important food source for many other animals
Subphylum Crustacea - Aquatic mandibulates
Class Malacostraca
about 20.000 species
Amphipoda
Decapoda
Isopoda - isopods
a few terrestrial species
woodlouse, pill bug
important edible species
also planctonic
hermit crab
crayfish
common
spiny
lobster
shrimp
crab
aquatic sowbug
lobster krill
Subphylum Hexapoda- Terrestial mandibulates
Springtails
(Collembola)
Edaphon (soil, leaf litter)
Class Insecta - insects
Class:
Entognatha
Subclass:
Apterygota
Subclass:
Pterygota
Class: Insecta, Ectognatha
Subphylum Hexapoda- Terrestial mandibulates
Class Insecta - insects
about 900.000 species
body tagmata - head, thorax, abdomen
four types of mouthparts
(1) chewing,
(2) piercing-sucking,
(3) sucking,
(1)
(4) sponging
thorax bears three pairs of jointed legs
and two pairs of wings (x primary wingless)
(2)
(3)
elytrae
(4)
silverfish
secondary wingless
METAMORPHOSIS
Hemimetabola
Holometabola (88% species)
eliminates intraspecific competition
(larva x imago)
Class Insecta - insects
about 900.000 species
hemimetabolous metamorphosis - nymphs are similar to adults
Odonata
Ephemeroptera
Mantodea
Blattodea
Orthoptera
Phasmatodea
Dermaptera
Psocoptera
Phthiraptera
Plecoptera
Isoptera
Hemiptera
Thysanoptera
Heteroptera
Homoptera
Class Insecta - insects
about 900.000 species
holometabolous metamorphosis - egg - larva - pupa - adults
Megaloptera Raphidoptera
Neuroptera
Mecoptera
Siphonaptera Hymenoptera
Lepidoptera
Trichoptera
Coleoptera
Strepsiptera
Diptera
RELATIVITY OF „BENEFIT“ AND„HARM“
–
• harmful insects – only 0,5 % species
• ectoparasites, vectors of diseases
• intermediate hosts of endoparasites
Anopheles
sucking lice
• storage pests
fleas
• pollination – in US annual
benefit worth of 19 billion dollars
• honey, beeswax; silk from silkworms
Honeybee (Apis mellifera)
cocroaches
Mealworm
(Tenebrio molitor)
Granary weevil
(Sitophilus granarius)
mill moth (Ephestia kuehniella)
silkworms
• predators, parasitoids
• pet animals
• laboratory experiments
• source of food for animals
and also for people
tse-tse fly (Glossina)
Drosophila
+
ladybug
sabre wasp
Thank you for your attention