Pentacrinites quenstedti

Overview

Pentacrinites quenstedti is a crinoid known for short stem segments and long cirri. Cirri with hook-like curved tips give it a distinctive appearance. Although its common group name, sea lily, evokes a flower, it was a marine animal.^[1]

Key facts

The cirri are described as long and flattened, with hook-shaped tips. The contrast between small stem segments and long cirri is characteristic. Comparing repeated hard parts reveals how a crinoid’s body is organized.^[1]

Time and place

It is studied through Early Jurassic Toarcian material from Ohmden in present-day Germany. The historical stratigraphic name Lias epsilon also appears in the literature. The entire Jurassic spanned approximately 200–140 million years ago.^[1][4]

The time range describes source context, not the complete duration of this species.

Size, form and skeleton

The species description centers on segments forming a short stem and long, flattened cirri. The curved tips of the cirri are also compared. Examining the stem and cirri separately highlights the contrast between short parts and long extensions.^[1]

A study treating Pentacrinites quenstedti as the same species as Pentacrinites dichotomus describes a large specimen held in Stuttgart with a stem reaching approximately 20 cm and arms approximately 15 cm long. It is presented as a crinoid with a very short stem.^[10]

Habitat and reproduction

Some researchers treated this name as the same species as Pentacrinites dichotomus. Comparative dichotomus material includes groups attached to wood. Small stem structures lead to questions about what the animal attached itself to during life.^[2][3]

Fossil discovery

Following descriptions of segments and cirri from Ohmden, later studies compared material of crinoids bearing other names. Hess and Simms proposed treating quenstedti as the same species as dichotomus. This shows how taxonomic choices affect which specimens are compared together.^[1][2]

References

1. Ohmden study — Pentacrinites quenstedti
2. Fossil Crinoids — Comparisons of Pentacrinites
3. Study — Life of drifting sea lilies
4. International Commission on Stratigraphy (2024) — Geological time chart
5. Oxford University Museum of Natural History — Gryphaea specimen J.43250
6. International Commission on Stratigraphy (2024) — Geological time chart
7. Lécuyer et al. (2025) — Pre-review manuscript on Gryphaea arcuata
8. Ohmden study — Pentacrinites quenstedti
9. International Commission on Stratigraphy (2024) — Geological time chart
10. Hess (1999), Ichthyosaurs and the largest sea lilies, Fossil Crinoids chapter 23

Research questions

Are a crinoid’s arms and stem always preserved together? Small hard parts, specimens with the stem and base of the crown connected, and wood bearing attached groups each provide different information. Examining these kinds of evidence separately helps connect body structure and lifestyle.^[1][2][3]

Observation

Move your gaze from the short stem segments to the long cirri. Imagining their flattened form and hooked tips reveals distinct features even within repeated structures.^[1]