Bilateria
The Bilateria are animals which are bilaterally symmetrical. They have front and a back end, an upside and downside, and a left and right side. Most animals are bilateral.
| Bilateria Temporal range: Ediacaran – Recent
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|---|---|
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| Diversity of bilaterians. | |
Scientific classification 
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| Kingdom: | Animalia |
| Clade: | ParaHoxozoa |
| Clade: | Bilateria |
Main subgroups
- Deuterostomia
- Echinodermata (20,000 species, 7000 living)
- Chordata. mostly Vertebrata (63,000 species)
- Hemichordata
- Protostomia
- Ecdysozoa (6 to 20 million species) [1]
- Nematoda (20,000 species known +many more)
- Arthropoda (one to 10 million species)
- Lophotrochozoa
- Annelida (17,000 species)
- Platyhelminthes (20,000+ species)
- Mollusca (85,000+ species)
- Brachiopoda (5,000 fossil species)
- Rhombozoa
- Platyzoa
- Minor phyla (like Chaetognatha)
- Ecdysozoa (6 to 20 million species) [1]
Numbers are approximate; extinct species numbers cannot be known for most phyla.
Bilateria Media
Idealised wormlike nephrozoan body plan. With a cylindrical body and a direction of movement the animal has head and tail ends. Sense organs and mouth form the basis of the head. Opposed circular and longitudinal muscles enable peristaltic motion.
Ikaria wariootia, living 571–539 million years ago is one of the oldest bilaterians identified
Cauliflour Jellyfish, Cephea cephea at Marsa Shouna, Red Sea, Egypt SCUBA
A remix of my previusly uploaded file DickinsoniaCostata.png , being more selevtive with sources.
Xenoturbella japonica holotype female. The white arrowhead indicates the ring furrow.
Proporus sp. -Acoela
Branchiostoma lanceolatum (Pallas, 1774)
Komodo National Park sea squirt (Polycarpa aurata)
Common carp (white background)
Vetulicolia
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Related pages
References
- ↑ Erwin T.L. 1982. Tropical forests: their richness in Coleoptera and other arthropod species. Coleopterists Bulletin. 36, 74/5. See also Coevolution#Numbers of species