# Dutch museum names Alsasuacaris dirkeysermansi: a 1.55 mm crustacean fossil from a Maastricht quarry

- Published: 2026-11-05 19:36 UTC
- Section: Life & Health › Biology & biochemistry
- Tags: Cyclida fossil, Alsasuacaris dirkeysermansi, Nationaal Oertijdmuseum, Maastricht quarry, extinct crustaceans, 66 million years old fossil, Dirk Eysermans, Jonathan Wallaard
- URL: https://realtech.media/news/rt-412a38806e8e3d52f4e19308_dutch_museum_names/

**The only known specimen of a new species of Cyclida, an extinct crustacean group with a few dozen known species, was found in a quarry near Maastricht.**

![Dutch museum names Alsasuacaris dirkeysermansi: a 1.55 mm crustacean fossil from a Maastricht quarry](https://sgzwpqqelzmajkcubgkl.supabase.co/storage/v1/object/public/rt-media/2026/11/16bdbe07c4f76031.webp)
*NOS*

Researchers at the Nationaal Oertijdmuseum in Boxtel have described a 1.55 mm fossil of a Cyclida, an extinct group of crustaceans, found in the chalky ground of a quarry near Maastricht, NOS reports. [1] The animal lived shortly before the dinosaurs died out, about 66 million years ago. [1] The museum says the find is of international importance. [1]

## Find and identification

The fossil collector Dirk Eysermans from Belgium brought the specimen to the museum two years ago. [1] At first it was unclear what the object was: a louse, a parasite or a crab-like animal were all considered. [1] It was also unclear which side of the animal was the top and which the bottom. [1]

Only a few dozen Cyclida species are known worldwide. [1] This is the only known specimen of its species, which was named Alsasuacaris dirkeysermansi after the finder. [1] According to curator Jonathan Wallaard, the fossil is now displayed in a museum case. [1]

## Open questions about Cyclida

It is still unknown which family the Cyclida belong to in evolutionary terms, how they lived and why they disappeared. [1] Although they resemble small crabs, scientists think they had a different role in the ecosystem of the ancient seas. [1] They lived at the same time as amphibians and marine reptiles, and when those reptiles vanished, the Cyclida disappeared too. [1]

The researchers suggest the Cyclida may have lived as a kind of parasite on the reptiles. [1] To test this they want to find more fossils. [1] Other material from the Maastricht quarry is still in the museum's preparation lab and will also be examined. [1] The researchers hope to find more such fossils, although the minuscule size makes this difficult. [1]

## Sources

1. [NOS](https://nos.nl/artikel/2638168-makkelijk-te-missen-maar-toch-gevonden-fossiel-van-66-miljoen-jaar-oud)

---

Source: RealTech, realtech.media — https://realtech.media/news/rt-412a38806e8e3d52f4e19308_dutch_museum_names/