Graptolite
Didymograptus
Tuning-fork graptolite
Didymograptus is the Ordovician 'tuning-fork' graptolite with two branches hanging from a single point, an index fossil for the Early–Middle Ordovician and common in Welsh, Scandinavian and Moroccan shales. Slabs from the Fezouata Formation and Wales carry dozens of specimens as flattened carbon films. Graptolites are cheap, scientifically important and often overlooked by collectors.
| Phylum | Hemichordata |
|---|---|
| Class | Graptolithina |
| Order | Graptoloidea |
| Family | Didymograptidae |
| Group | Graptolite |
| Rank (PBDB) | genus· Paleobiology Database |
| Author | McCoy 1851· Paleobiology Database |
| Classification (PBDB) | Hemichordata › Pterobranchia › Graptoloidea › Dichograptidae· Paleobiology Database |
| Range (PBDB) | 489–443 Ma· Paleobiology Database |
| PBDB occurrences | 433· Paleobiology Database |
Elsewhere
- WoRMS AphiaID: 411414
- GBIF: 5429354
- PBDB: 33655
- Wikidata: Q2153216
- PBDB taxon page
- Wikipedia: Didymograptus
- PBDB search: Didymograptus
Cite this article
Stratum Study. "Didymograptus" (Taxon). Stratum Study pack 2026.09, as of 2026-09-19. https://stratum.black/study/taxa/didymograptus. Accessed 2026-09-20.
@misc{stratum-didymograptus,
title = {Didymograptus},
author = {{Stratum Study}},
howpublished = {\url{https://stratum.black/study/taxa/didymograptus}},
year = {2026},
note = {Taxon article, Stratum Study pack 2026.09, as of 2026-09-19; sources: stratum, pbdb, wikidata, commons. Accessed 2026-09-20.}
} Citations carry the pack version and the article's as-of date so they resolve to the same text later. The facts themselves belong to the sources listed below; cite those for the science.