Taxonomy
Spiders are divided into two sub-orders, Mesothelae and Opisthothelae, of which the latter contains two infra-orders, Mygalomorphae and Araneomorphae. Over 40,000 living species of spiders (order Araneae) have been identified and are currently grouped into about 110 families and about 3,700 genera by arachnologists.
| Spider diversity | Features | ||||||
| Sub-order | Species | Genera | Families | Segmented plates on top of abdomen | Ganglia in abdomen | Spinnerets | Striking direction of fangs |
|---|---|---|---|---|---|---|---|
| Mesothelae | 87 | 5 | 1 | Yes | Yes | Four pairs, in some species one pair fused, under middle of abdomen | Downwards and forwards |
| Mygalomorphae | 2,600 | 300 | 15 | No, but yes in some fossils | No | One, two or three pairs under rear of abdomen | |
| Araneomorphae | 37,000 | 3,400 | 93 | From sides to center, like pincers | |||
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