Invertebrate Diversity
Chapter 33
The Ancestors
• Protists: Choanoflagellates
– Colonies formed/ turned into super
colonies
Porifera – The Sponges
Porifera – The Sponges
• Asymmetrical body plan
• No tissue layer
• Sexual reproduction hemaphroditic
• Sessile filter feeder
• Grouped based on
“skeleton” type.
• Can form gemmules for
protection.
Gemmules
Cnidaria
• Examples: jellyfish, anemones, hydra and
coral
Cnidaria
• Named for cnidocytes
Cnidaria
• Diploblastic
• Two body forms: polyp & medusa
• Grouped based on amount of life spent as
polyp or medusa
Cnidaria
Platyhelminthes - Flatworms
• Examples: planaria, liver flukes, tapeworms
Platyhelminthes - Flatworms
• Bilateral symmetry
• Simple organ
systems
• Reproduce sexually
and asexually
• Acoelomate
• Triploblasitc
• Most are parasitic
Rotifera
 Named for feeding rotors
 Pseudocoelomates
 Reproduce via parthenogenisis
 Have an anus!

Images from http://www.microscopy-uk.org.uk
Nematoda – Roundworms
• Found in most aquatic habitats, soil, and in plant and animal tissues
• Parasitic – hookworms, pinworms, round worms, heart worms
.
Nematoda – Roundworms
• Pseudocoelomates
• Simple organs
Annelida – Segmented Worms
• Examples: earthworms, fireworms, leeches
Annelida – Segmented Worms
• “Little rings” –repeating segments, some
specialized
• Coelomates
• Setae
• Parapodia
Annelida – Segmented Worms
• Fairly complex anatomy
Mollusca
• Largest classes:
– Gastropods
– Bivalves
– Cephalopods
Mollusca
Muscular foot
Visceral Mass
Head
• “Jointed foot”
Arthropoda
• Crustaceans-hexapods-myriapods-cheliceroforms
Arthropoda
• Most successful animal phyla – 67% of all
species!
•
•
•
•
•
Arthropoda
Exoskeleton – ecdysis
Open circulatory system
Tracheal tubes
Spiracels vs. book lungs
Malpighian tubules
Echinodermata
•
•
•
•
•
•
•
•
“Spiny Skin”
No head or brain
Radial symmetry
Simple anatomy
Deuterostomes
Endoskeleton
Tube feet
Water vascular system
classification
Kingdom:
Animalia
Phylum:
Arthropoda
Class:
Arachnida
Order:
Araneae
Family:
Theridiidae
Genus:
Latrodectus
Species
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Latrodectus Walckenaer, 1805
Latrodectus antheratus (Badcock, 1932) — Paraguay, Argentina
Latrodectus apicalis Butler, 1877 — Galapagos Islands
Latrodectus bishopi Kaston, 1938 — USA
Latrodectus cinctus Blackwall, 1865 — Cape Verde Islands, Africa, Kuwait
Latrodectus corallinus Abalos, 1980 — Argentina
Latrodectus curacaviensis (Müller, 1776) — Lesser Antilles, South America
Latrodectus dahli Levi, 1959 — Middle East to Central Asia
Latrodectus diaguita Carcavallo, 1960 — Argentina
Latrodectus elegans Thorell, 1898 — China, Myanmar, Japan
Latrodectus erythromelas Schmidt & Klaas, 1991 — Sri Lanka
Latrodectus geometricus C. L. Koch, 1841 — Cosmopolitan
Latrodectus hasselti Thorell, 1870 — Southeast Asia to Australia, New Zealand
Latrodectus hesperus Chamberlin & Ivie, 1935 — North America, Israel
Latrodectus hystrix Simon, 1890 — Yemen, Socotra
Latrodectus indistinctus O. P.-Cambridge, 1904 — Namibia, South Africa
Latrodectus karrooensis Smithers, 1944 — South Africa
Latrodectus katipo Powell, 1871 — New Zealand
Latrodectus lilianae Melic, 2000 — Spain
Latrodectus mactans (Fabricius, 1775) — probably native to North America only (introduced elsewhere)
Latrodectus menavodi Vinson, 1863 — Madagascar, Comoro Islands
Latrodectus mirabilis (Holmberg, 1876) — Argentina
Latrodectus obscurior Dahl, 1902 — Cape Verde Islands, Madagascar
Latrodectus pallidus O. P.-Cambridge, 1872 — Cape Verde Islands, Libya to Russia, Iran
Latrodectus quartus Abalos, 1980 — Argentina
Latrodectus renivulvatus Dahl, 1902 — Africa, Saudi Arabia, Yemen
Latrodectus revivensis Shulov, 1948 — Israel
Latrodectus rhodesiensis Mackay, 1972 — Southern Africa
Latrodectus tredecimguttatus (Rossi, 1790) — Mediterranean to China
Latrodectus variegatus Nicolet, 1849 — Chile, Argentina
Latrodectus variolus Walckenaer, 1837 — USA, Canada