Marine biology etextbook
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There are over one million species of animals that have been described. Some
biologists estimate that up to 50 million more remain to be discovered. Of those that have
been described, approximately 86% are insects. About 300,000 species are beetles (order Coleoptera ).
The numbers of described species in each phylum of animals (other than the insects ) are shown below.
Note that these are only rough estimates. The estimates from other sources may vary considerably.
|
PHYLUM
| Numbers of Living Species of Animals
(exclusive of insects)
|
No. Species |
| Arthropoda |
| 97,000 |
| Mollusca |
| 50,000 |
| Vertebrata |
| 47,000 |
| Protozoa |
| 35,000 |
| Platyhelminthes |
| 20,000 |
| Annelida |
| 15,000 |
| Nematoda |
| 12,000* |
| Porifera |
| 9,000 |
| Cnidaria |
| 9,000 |
| Echinodermata |
| 7,000 |
| Ectoprocta |
| 4,500 |
| Urochordata |
| 3,000 |
| Rotifera |
| 1,800 |
| Nemertea |
| |
900 |
| Acanthocephala |
| |
700 |
| Gastrotricha |
| |
450 |
| Tardigrada |
| |
400 |
| Sipuncula |
| |
250 |
| Nematamorpha |
| |
230 |
| Kinorhyncha |
| |
150 |
| Entoprocta |
| |
150 |
| Pogonophora |
| |
135 |
| Echiura |
| |
135 |
| Chaetognatha |
| |
100 |
| Ctenophora |
| |
100 |
| Mesozoa |
| |
100 |
| Hemichordata |
| |
85 |
| Onycophora |
| |
80 |
| Gnathostomulida |
| |
80 |
| Cephalochordata |
| |
23 |
| Phoronida |
| |
15 |
| Priapula |
| |
15 |
| Loricifera |
| |
9+ |
| Vestimentifera |
| |
8 |
| Placozoa |
| |
1 |
|
* There are probably many more species that are yet undescribed
References:
Barnes, 1980
Brusca & Brusca, 2003
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