Phylogenetic position and stratigraphic uncertainty of a new flexible crinoid from the Ordovician–Silurian boundary of Anticosti Island (Quebec, Canada)

Fossil crinoids from the Ordovician–Silurian boundary interval (~ 443.8 million years) are known from relatively few locations worldwide due to a near-global unconformity that formed from eustatic sea level fall. This rock record bias has severely hindered study of the timing, magnitude, biogeographic signature, and extinction mechanisms of the Late Ordovician mass extinction (LOME). Crinoids underwent a significant faunal transition between the Late Ordovician and early Silurian that resulted in major shifts between dominant clades, but the driving mechanisms and precise timing of this transition remain unclear. Anticosti Island (Quebec, Canada) preserves one of the few Late Ordovician–early Silurian successions of highly fossiliferous, shallow-water rocks that includes the O–S boundary, making fossils from this region instrumental for better understanding the LOME and Ordovician–Silurian crinoid faunal turnover.
Here, we report on a new flexible crinoid, Anticosticrinus natiscotecensi..., , # Phylogenetic position and stratigraphic uncertainty of a new flexible crinoid from the Ordovician–Silurian boundary of Anticosti Island (Quebec, Canada)

Dataset DOI: [10.5061/dryad.dz08kps8b](10.5061/dryad.dz08kps8b)

## Description of the data and file structure

Nexus file containing character data for 25 species of flexible crinoids and commands to conduct the three phylogenetic analyses presented in: Cole, Wright, and Hopkins, Phylogenetic position and stratigraphic uncertainty of a new flexible crinoid from the Ordovician-Silurian boundary of Anticosti Island (Quebec, Canada), Journal of Paleontology.

### Files and variables

#### File: Flexibles\_phylogenetic\_analyses.nex

**Description:** This nexus file includes a summary of the characters and character states associated with the matrices/analyses; and character data and commands to run the following three phylogenetic analyses:

(1): Maximum parsimony (PAUP*)

(2): Bayesian inference (topology only; MrBayes)

(3): Bayesian...,