Tetragraptus approximatus
| Tetragraptus approximatus Temporal range: | |
|---|---|
| Illustration of Tetragraptus approximatus | |
| Original illustrations of Tetragraptus approximatus by Nicholson (1873). At the top is a magnified section of the stipes. A complete specimen is illustrated below. | |
| Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Hemichordata |
| Class: | Pterobranchia |
| Order: | †Graptoloidea |
| Family: | †Dichograptidae |
| Genus: | †Tetragraptus |
| Species: | †T. approximatus |
| Binomial name | |
| †Tetragraptus approximatus Nicholson, 1873 | |
Tetragraptus approximatus is a species of dichograptid graptolite belonging to the genus Tetragraptus. It existed during the Floian Age (477.1 million years ago) of the Ordovician. It is an important index fossil in biostratigraphy.