Chondrichthyans from the of Colorado

Wayne Itano, Boulder, Colorado Karen Houck, Eastern Kentucky Univ. Martin Lockley, Univ. Colorado, Denver Pennsylvanian Paleogeography

McCoy, Colorado

R. Blakey, Northern Arizona University Southwestern US during the Pennsylvanian (R. Blakey, Northern Ariz. Univ.) McCoy, Colorado spine, 10 August 1991

Ctenacanthus 18 cm 18 sp., Minturn Formation, sp., Minturn Eagle County, Colorado County, Eagle Pennsylvanian (late Atokan), Pennsylvanian

Ctenacanthus Ctenacanthus spine

C. buttersi

Ctenacanthus McCoy from Univ. Colorado Museum Colorado from Univ. St. John & Worthen & John St. spines compared with compared spines

Ctenacanthus

Ctenacanthus buttersi Ctenacanthus McCoy McCoy spine compared to “Ctenacanthus” furcicarinatus Newberry

1 cm

“Ctenacanthus” furcicarinatus Close-up of costae Large-noded spine fragment & Bythiacanthus siderius (Leidy)

1 cm Bythiacanthus siderius St. John & Worthen

A. gracillis sp. 1 cm

Acondylacanthus Physonemus acinaciformis sp.? 1 cm

Physonemus

[Xystracanthus, Batacanthus, Drepanacanthus??] Batacanthus, [Xystracanthus, sp. 5 mm

Petrodus

Petrodus patelliformis Petalodont Teeth All bars = 1 cm

Polyrhizodus sp. Janassa sp.

Anterior

Lateral Peripristis semicircularis Petalodus ohioensis “Cladodus” occidentalis Leidy [Not reniforme Cope]

1 cm

1 cm

1 cm Courtesy of R. Troll sp.

Edestus 1 cm

Edestus heinrichsi Holocephalian tooth plates

1 cm

1 cm

sp. Sandalodus 1 cm

Lagarodus angustus Cochliodont anterior tooth? 5 mm

Unidentified tooth Most Abundant Teeth at 1 Locality

193 Petalodus ohioensis 73 “Cladodus” occidentalis 20 Deltodus sp. 15 Lagarodus angustus 10 cochliodont indet. Conclusions

• The Minturn Formation has a diverse chondrichthyan fauna, associated with a rich benthic invertebrate fauna • Most taxa are known from elsewhere in North America • “Cladodus” occidentalis teeth may be associated with Ctenacanthus cf. buttersi finspines • Other Colorado formations contain chondrichthyan faunas which have not been studied Acknowledgments Specimens Access to collections • Bill Bateman • John Maisey (AMNH) • Helen Dyer • Peter Robinson (Univ. Colo.) • Doug Nelson • Mary Ann Turner (Yale) • Jack Null • Jordan Sawdo • Bernie Spilka • Steve Thompson

Graphics

Identifications • Ron Blakey • Michael Hansen • Ray Troll • John Maisey • Barbara Stahl